MP MATERIALS CORP. / DE, 10-K filed on 2/26/2026
Annual Report
v3.25.4
COVER - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2025
Feb. 20, 2026
Jun. 30, 2025
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2025    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 001-39277    
Entity Registrant Name MP Materials Corp. / DE    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 84-4465489    
Entity Address, Address Line One 1700 S. Pavilion Center Drive, Suite 800    
Entity Address, City or Town Las Vegas    
Entity Address, State or Province NV    
Entity Address, Postal Zip Code 89135    
City Area Code 702    
Local Phone Number 844-6111    
Title of 12(b) Security Common Stock, par value of $0.0001 per share    
Trading Symbol MP    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Entity Shell Company false    
Entity Public Float     $ 5.0
Entity Common Stock, Shares Outstanding   177,667,450  
Documents Incorporated by Reference Portions of the registrant’s definitive 2026 proxy statement, anticipated to be filed with the Securities and Exchange Commission within 120 days after the end of the registrant’s fiscal year, are incorporated by reference into Part III of this Form 10-K.    
Amendment Flag false    
Entity Central Index Key 0001801368    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Document Financial Statement Error Correction false    
v3.25.4
AUDIT INFORMATION
 12 Months Ended
Dec. 31, 2025
Audit Information [Abstract]  
Auditor Name KPMG LLP
Auditor Location Denver, CO
Auditor Firm ID 185
v3.25.4
CONSOLIDATED BALANCE SHEETS - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Current assets    
Cash and cash equivalents $ 1,166,011 $ 282,442
Short-term investments 664,275 568,426
Total cash, cash equivalents and short-term investments 1,830,286 850,868
Trade accounts receivable, net of allowance for credit losses of $0 and $0, respectively (including related party) 14,642 18,645
Income taxes receivable 1,004 23,672
Other receivables 131,038 20,599
Inventories 171,560 107,905
Prepaid expenses and other current assets 17,271 9,633
Total current assets 2,165,801 1,031,322
Non-current assets    
Property, plant and equipment, net 1,369,817 1,251,496
Inventories 80,539 19,031
Price protection agreement upfront asset, net 209,668 0
Other non-current assets 38,335 31,709
Total non-current assets 1,698,359 1,302,236
Total assets 3,864,160 2,333,558
Current liabilities    
Accounts and construction payable 36,655 23,562
Accrued liabilities 95,086 64,727
Current portion of long-term debt 67,411 0
Deferred revenue 74,301 56,880
Other current liabilities 25,596 18,850
Total current liabilities 299,049 164,019
Non-current liabilities    
Long-term debt, net of current portion 931,330 908,729
Deferred revenue 83,889 43,120
Deferred government grant 22,101 20,087
Deferred investment tax credit 26,860 25,502
Deferred income taxes 51,558 85,309
Other non-current liabilities 57,005 31,912
Total non-current liabilities 1,172,743 1,114,659
Total liabilities 1,471,792 1,278,678
Commitments and contingencies (Note 13)
Redeemable preferred stock 413,611 0
Stockholders’ equity:    
Preferred stock, undesignated ($0.0001 par value, 49,600,000 and 50,000,000 shares authorized as of December 31, 2025, and December 31, 2024, respectively, zero issued and outstanding in either year) 0 0
Common stock ($0.0001 par value, 450,000,000 shares authorized, 192,607,429 and 178,445,570 shares issued, and 177,357,647 and 163,195,788 shares outstanding, as of December 31, 2025, and December 31, 2024, respectively) 19 18
Additional paid-in capital 1,970,970 961,434
Retained earnings 234,428 320,302
Accumulated other comprehensive income 387 173
Treasury stock, at cost, 15,249,782 shares for both periods (227,047) (227,047)
Total stockholders’ equity 1,978,757 1,054,880
Total liabilities, redeemable preferred stock and stockholders’ equity $ 3,864,160 $ 2,333,558
Common stock, par value (usd per share) $ 0.0001 $ 0.0001
v3.25.4
CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Allowance for credit losses $ 0 $ 0
Redeemable preferred stock, par value (in USD per share) $ 0.0001 $ 0.0001
Redeemable preferred stock, authorized (in shares) 400,000 0
Redeemable preferred stock, issued (in shares) 400,000 0
Redeemable preferred stock, outstanding (in shares) 400,000 0
Redeemable preferred stock, liquidation preference $ 413,489,000 $ 0
Preferred stock, par value (usd per share) $ 0.0001 $ 0.0001
Preferred stock, authorized (shares) 49,600,000 50,000,000
Preferred stock, issued (shares) 0 0
Preferred shares, outstanding (shares) 0 0
Common stock, authorized (shares) 450,000,000 450,000,000
Common stock, issued (shares) 192,607,429 178,445,570
Common stock, outstanding (shares) 177,357,647 163,195,788
Treasury stock (in shares) 15,249,782 15,249,782
v3.25.4
CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Statement [Abstract]      
Revenue (including related party) $ 224,441 $ 203,855 $ 253,445
Price protection agreement income 51,016 0 0
Operating costs and expenses:      
Cost of sales (excluding depreciation, depletion and amortization) (including related party) 192,789 192,586 92,714
Selling, general and administrative 112,066 83,299 79,245
Depreciation, depletion and amortization 89,267 78,057 55,709
Start-up costs 4,286 5,684 21,330
Advanced projects and development 24,208 9,307 14,932
Other operating costs and expenses 2,215 4,348 7,234
Total operating costs and expenses, net 424,831 373,281 271,164
Operating loss (149,374) (169,426) (17,719)
Interest expense, net (31,481) (23,010) (5,254)
Gain on early extinguishment of debt 0 52,911 0
Other income, net 63,081 46,178 56,048
Income (loss) before income taxes (117,774) (93,347) 33,075
Income tax benefit (expense) 31,900 27,923 (8,768)
Net income (loss) $ (85,874) $ (65,424) $ 24,307
Earnings (loss) per common share:      
Basic (in USD per share) $ (0.50) $ (0.39) $ 0.14
Diluted (in USD per share) $ (0.50) $ (0.57) $ 0.14
Weighted-average shares outstanding:      
Basic (in shares) 170,126,753 166,840,611 177,181,661
Diluted (in shares) 170,126,753 169,882,640 178,152,212
v3.25.4
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Statement of Comprehensive Income [Abstract]      
Net Income (Loss) $ (85,874) $ (65,424) $ 24,307
Change in net unrealized gains (losses) on available-for-sale securities 214 28 (44)
Total comprehensive income (loss) $ (85,660) $ (65,396) $ 24,263
v3.25.4
CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY - USD ($)
$ in Thousands
Total
Series A Convertible Preferred Stock
Preferred Stock, Undesignated
Common Stock
Additional Paid-in Capital
Retained Earnings
Accumulated Other Comprehensive Income
Treasury Stock
Beginning balance (shares) at Dec. 31, 2022   0 0 177,706,608        
Beginning balance at Dec. 31, 2022 $ 1,312,634   $ 0 $ 18 $ 951,008 $ 361,419 $ 189 $ 0
Beginning balance at Dec. 31, 2022   $ 0            
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Stock-based compensation (shares)       472,047        
Stock-based compensation 27,104       27,104      
Shares used to settle payroll tax withholding (shares)       (248,776)        
Shares used to settle payroll tax withholding (7,185)     $ (1) (7,184)      
Common stock issued to acquire intangible assets (in shares)       152,504        
Common stock issued to acquire intangible assets 8,963       8,963      
Net Income (Loss) 24,307         24,307    
Other comprehensive income (loss), net of tax (44)           (44)  
Ending balance (shares) at Dec. 31, 2023   0 0 178,082,383        
Ending balance at Dec. 31, 2023   $ 0            
Ending balance at Dec. 31, 2023 1,365,779   $ 0 $ 17 979,891 385,726 145 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Stock-based compensation (shares)       662,887        
Stock-based compensation 23,506       23,505      
Stock-based compensation       $ 1        
Shares used to settle payroll tax withholding (shares)       (583,936)        
Shares used to settle payroll tax withholding $ (10,112)       (10,112)      
Repurchases of common stock (in shares) (15,200,000)     (15,249,782)        
Repurchases of common stock $ (227,047)             (227,047)
Common stock issued for services (in shares)       240,663        
Common stock issued for services 3,737       3,737      
Common stock issued to acquire intangible assets (in shares)       43,573        
Common stock issued to acquire intangible assets 0       0      
Capped call options, net of tax (49,413)       (49,413)      
Substantial premium on convertible debt, net of tax 13,826       13,826      
Net Income (Loss) (65,424)         (65,424)    
Other comprehensive income (loss), net of tax 28           28  
Ending balance (shares) at Dec. 31, 2024   0 0 163,195,788        
Ending balance at Dec. 31, 2024 0 $ 0            
Ending balance at Dec. 31, 2024 1,054,880   $ 0 $ 18 961,434 320,302 173 227,047
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of Series A Preferred Stock (in shares)   400,000            
Issuance of Series A Preferred Stock, net of issuance costs   $ 413,611            
Stock-based compensation (shares)       788,769        
Stock-based compensation 31,033       31,033      
Shares used to settle payroll tax withholding (shares)       (318,460)        
Shares used to settle payroll tax withholding (10,919)       (10,919)      
Common stock issued (shares)       13,590,908        
Common stock issued upon public offering, net of issuance costs $ 724,209     $ 1 724,208      
Repurchases of common stock (in shares) 0              
Common stock issued for services (in shares)       55,920        
Common stock issued for services $ 4,038       4,038      
Common stock issued to acquire intangible assets (in shares)       43,573        
Common stock issued to acquire intangible assets 0       0      
Issuance of warrant, net of issuance costs 261,176       261,176      
Net Income (Loss) (85,874)         (85,874)    
Other comprehensive income (loss), net of tax 214           214  
Other (in shares)       1,149        
Other 0              
Ending balance (shares) at Dec. 31, 2025   400,000 0 177,357,647        
Ending balance at Dec. 31, 2025 413,611 $ 413,611            
Ending balance at Dec. 31, 2025 $ 1,978,757   $ 0 $ 19 $ 1,970,970 $ 234,428 $ 387 $ 227,047
v3.25.4
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Operating activities:      
Net Income (Loss) $ (85,874) $ (65,424) $ 24,307
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:      
Depreciation, depletion and amortization 89,267 78,057 55,709
Accretion of discount on short-term investments (24,087) (30,255) (26,316)
Gain on early extinguishment of debt 0 (52,911) 0
Stock-based compensation expense 30,163 23,183 25,236
Amortization of debt discount and debt issuance costs 5,412 3,901 3,536
Write-downs of inventories 3,038 21,527 2,285
Deferred income taxes (30,393) (27,775) 8,455
Other (7,082) 4,837 1,716
Decrease (increase) in operating assets:      
Trade accounts receivable (including related party) 4,003 (8,931) 23,133
Income taxes receivable 22,668 (22,842) 1,371
Other receivables (110,439) (36) (18,028)
Inventories (115,019) (41,537) (47,099)
Prepaid expenses, other current and non-current assets (8,959) (1,676) (574)
Increase (decrease) in operating liabilities:      
Accounts payable and accrued liabilities 9,392 1,332 11,305
Income taxes payable 360 0 (21,163)
Deferred revenue 58,190 100,000 0
Deferred government grant 4,826 4,911 19,120
Other current and non-current liabilities (1,221) 26,988 (294)
Net cash provided by (used in) operating activities (155,755) 13,349 62,699
Investing activities:      
Additions to property, plant and equipment (172,375) (186,418) (261,897)
Purchases of short-term investments (1,819,026) (1,567,983) (1,185,477)
Proceeds from sales of short-term investments 176,074 166,371 507,736
Proceeds from maturities of short-term investments 1,571,342 1,597,991 1,015,190
Investment in equity method investee 0 0 (9,673)
Proceeds from return of investment in equity method investee 9,673 0 0
Proceeds from sale of property, plant and equipment 4,063 0 18
Proceeds from government awards used for construction 24,200 96 2,800
Net cash provided by (used in) investing activities (206,049) 10,057 68,697
Financing activities:      
Proceeds from issuance of long-term debt 61,540 747,500 0
Proceeds from issuance of common stock 747,500 0 0
Proceeds from issuance of Series A preferred stock 299,402 0 0
Proceeds from issuance of warrant 189,058 0 0
Payment of debt issuance costs (3,780) (20,648) 0
Payments to retire long-term debt 0 (428,599) 0
Payment of equity issuance costs (31,104) 0 0
Purchase of capped call options 0 (65,332) 0
Repurchases of common stock 0 (225,068) 0
Principal payments on debt obligations (6,137) (2,532) (2,732)
Tax withholding on stock-based awards (10,919) (10,112) (7,185)
Net cash provided by (used in) financing activities 1,245,560 (4,791) (9,917)
Net change in cash, cash equivalents and restricted cash 883,756 18,615 121,479
Cash, cash equivalents and restricted cash beginning balance 283,603 264,988 143,509
Cash, cash equivalents and restricted cash ending balance 1,167,359 283,603 264,988
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]      
Cash and cash equivalents 1,166,011 282,442 263,351
Restricted cash, current 810 812 1,290
Restricted cash, non-current 538 349 347
Total cash, cash equivalents and restricted cash $ 1,167,359 $ 283,603 $ 264,988
v3.25.4
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
 12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
Description of Business: MP Materials Corp., including its subsidiaries (the “Company” or “MP Materials”), is the largest producer of rare earth materials in the Western Hemisphere. Headquartered in Las Vegas, Nevada, the Company owns and operates the Mountain Pass Rare Earth Mine and Processing Facility (“Mountain Pass”) located near Mountain Pass, San Bernardino County, California, the only rare earth mining and processing site of scale in North America. Rare earth products are critical inputs in hundreds of existing and emerging clean-tech applications including electric vehicles and wind turbines as well as robotics, drones, and defense applications. Additionally, the Company owns and operates a rare earth metal, alloy and magnet manufacturing facility in Fort Worth, Texas (the “Independence Facility”), where the Company produces and sells magnetic precursor products and commenced manufacturing of neodymium-iron-boron (“NdFeB”) permanent magnets in December 2025. The Company’s operations are organized into two reportable segments: Materials and Magnetics. See Note 22, “Segment Reporting,” for additional information.
The Materials segment represents the upstream and midstream operations of the Company, which primarily consist of Mountain Pass, a fully integrated mining and refining facility producing refined rare earth oxides and related products. The Materials segment generates revenue primarily from sales of neodymium-praseodymium (“NdPr”) oxide and metal, primarily sold to customers in Japan, South Korea, and broader Asia. The Materials segment historically generated the majority of its revenue from sales of rare earth concentrate primarily to a distributor that, in turn, typically sold that product to refiners in China.
The Magnetics segment represents the downstream magnet manufacturing and related operations of the Company, which currently consist of the Independence Facility, a fully integrated metal, alloy, and magnet manufacturing plant. The Magnetics segment began generating revenue from sales of magnetic precursor products to General Motors Company (NYSE: GM) (“GM”) in the U.S. in the first quarter of 2025.
On July 9, 2025, the Company entered into definitive agreements with the United States Department of War (the “DoW”), formerly known as the Department of Defense, (collectively, the “DoW Transaction Agreements”) establishing a transformational public-private partnership with the DoW to accelerate the build-out of an end-to-end U.S. rare earth magnet supply chain and reduce foreign dependency (the “DoW Transactions”). This partnership is further described in Note 3, “Public-Private Partnership with U.S. Department of War,” which includes certain defined terms related to the DoW Transaction Agreements.
In connection with the DoW Transactions, the Company will expand its Independence Facility, construct a second domestic magnet manufacturing facility (the “10X Facility”) and extend its heavy rare earth elements (“HREE”) refining capability at Mountain Pass. Additionally, as outlined in the DoW Offtake Agreement, the DoW has guaranteed that the 10X Facility will generate at least $140 million of EBITDA (as defined in the DoW Offtake Agreement, and subject to annual escalation) and has the right to purchase all of the magnets produced at the 10X Facility (which may instead be commercially syndicated). Separately, the Company entered into an NdPr price floor protection agreement with the DoW (the “Price Protection Agreement” or “PPA”) for the Company’s NdPr products produced at Mountain Pass that are sold or produced and stockpiled starting in the fourth quarter of 2025.
The cash flows and profitability of the Company’s operations have historically been significantly affected by the market price of rare earth products, which are generally also impacted by taxes and tariffs. While this volatility will be reduced following the effectiveness of the PPA, certain exposure to market prices remains. The prices of rare earth products are affected by numerous factors beyond the Company’s control. The products of the Company are sold globally, with a focus on accelerating the development of a U.S. supply chain, with export products primarily sold in the Asian market due to the metallization and magnet manufacturing capabilities of the region. See the “Concentration of Risk” section in Note 2, “Significant Accounting Policies,” for additional information.
Basis of Presentation: The Consolidated Financial Statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”), with the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”), and are presented in U.S. dollars.
v3.25.4
SIGNIFICANT ACCOUNTING POLICIES
 12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
SIGNIFICANT ACCOUNTING POLICIES SIGNIFICANT ACCOUNTING POLICIES
Principles of Consolidation: The Consolidated Financial Statements include the accounts of MP Materials Corp. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Concentration of Credit Risk: Financial instruments that potentially subject the Company to credit risk consist principally of cash, cash equivalents and short-term investments, and receivables from customers. The Company believes that its credit risk is limited because the Company’s current contracts are with companies that have a reliable payment history. The Company does not believe that it is exposed to any significant risks related to its cash accounts, money market funds, or short-term investments.
Concentration of Customer Risk: The concentration of customer risk arises when a significant portion of the Company’s revenue is generated from a small group of customers. Reduction of orders, delay of payments, or termination of contracts by these key customers could have a significant negative effect on the Company’s results of operations and cash flows. The Company’s revenue is derived from sales of rare earth products and, historically, from sales of rare earth concentrate to China, which ceased in July 2025 to align with the terms of the DoW Transaction Agreements. Rare earth concentrate is not quoted on any major commodities market or exchange, and demand is currently constrained to a relatively limited number of refiners, the majority of which are based in China.
For the year ended December 31, 2025, Customers A and B in the Materials segment accounted for 30% and 23% of the Company’s total revenue, respectively; Customer C, primarily in the Magnetics segment, accounted for 31% of the Company’s total revenue. For the year ended December 31, 2024, Customers B and A in the Materials segment accounted for 78% and 20% of the Company’s total revenue, respectively. For the year ended December 31, 2023, Customer B in the Materials segment accounted for 96% of the Company’s total revenue.
Use of Estimates: The preparation of the Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities, (ii) the disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements, and (iii) the reported amounts of revenues and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions relate to the useful lives and recoverability of long-lived assets (such as the effects of mineral reserves and cash flows from operating the mine in determining the life of the mine); government grants; investment tax credits; the valuation allowance of deferred tax assets; asset retirement and environmental obligations; determining the net realizable value of inventories; and estimating the Company’s expected pattern of economic benefit of the PPA Upfront Asset (as defined below). Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Accordingly, actual results may differ from those estimates.
Segment Reporting: Accounting Standards Codification (“ASC”) 280, “Segment Reporting,” (“ASC 280”) establishes standards for entities on how to report information about operating segments on a basis consistent with an entity’s internal organizational structure as well as information about an entity’s products and services, the geographical areas in which it operates and its major customers. Operating segments are defined as components of an enterprise engaged in business activities from which it may recognize revenues and incur expenses, about which discrete financial information is available and evaluated regularly by the chief operating decision maker (“CODM”), or decision-making group, in deciding how to allocate resources and in assessing performance. See Note 22, “Segment Reporting,” for additional information on the Company’s reportable segments.
Cash, Cash Equivalents and Investments: Cash and cash equivalents consist of all cash balances and highly liquid investments, including commercial paper, certificates of deposit, and U.S. treasury and agency securities, with a maturity of three months or less at the time of purchase.
The Company’s investments in U.S. treasury and agency securities, commercial paper, and certificates of deposit have been classified and accounted for as available-for-sale securities and the Company re-evaluates the classification each reporting period. The Company classifies its available-for-sale securities that do not otherwise meet the requirements to be accounted for as cash equivalents as either current or non-current based on each instrument’s underlying contractual maturity date as well as the Company’s expectations of sales and redemptions within the next twelve months. See Note 4, “Cash, Cash Equivalents and Investments,” for additional information.
Available-for-sale securities are recorded at fair value each reporting period. For unrealized losses in securities that the Company intends to hold and will not more likely than not be required to sell before recovery, the Company further evaluates whether declines in fair value below amortized cost are due to credit or non-credit related factors. The Company considers credit related impairments to be changes in value that are driven by a change in the creditor’s ability to meet its payment obligations and records an allowance and recognizes a corresponding loss when the impairment is incurred.
Unrealized non-credit related losses and unrealized gains are reported, net of income taxes, in “Accumulated other comprehensive income” within the Company’s Consolidated Balance Sheets, until realized. Realized gains and losses are determined based on the specific identification method and are reported in “Other income, net” within the Company’s
Consolidated Statements of Operations upon realization. Premiums and discounts are amortized or accreted over the life of the related available-for-sale security as an adjustment to yield using the straight-line method. Interest income is recognized when earned. These amounts are reported in “Other income, net” within the Company’s Consolidated Statements of Operations.
Trade Accounts Receivable: Trade accounts receivable pertain to receivables arising from contracts with customers and do not bear interest. The Company evaluates its estimate of expected credit losses based on historical experience and current economic conditions for each portfolio of customers, though at present, the amounts are concentrated among a limited number of customers. As of December 31, 2025 and 2024, the Company did not have an allowance for expected credit losses, as principally all of the Company’s receivables are from a limited number of customers, with no history or expectation of uncollectible amounts.
Inventories: Inventories consist of raw materials, supplies, mined ore stockpiles, work in process, and finished goods. Raw materials and supplies consist of spare parts, reagent chemicals, maintenance supplies, packaging materials and other consumables used in the production of rare earth products and magnetic precursor products. Mined ore stockpiles represent bastnaesite ore that has been mined and stockpiled for future processing. Work in process consists of bastnaesite ore and separated rare earth products in various stages of the production process, as well as finished and packaged NdPr oxide shipped to tollers for processing into NdPr metal. Work in process also includes packaged bastnaesite concentrate that has been stockpiled for future processing into separated rare earth products, including quantities which the Company elected to designate as NdPr Products for purposes of the PPA (as such terms are defined in Note 3, “Public-Private Partnership with U.S. Department of War”). Finished goods primarily consist of packaged NdPr oxide and NdPr metal (including quantities tolled) that are ready for sale. Raw materials, mined ore stockpiles, work in process, and finished goods are carried at weighted average cost. Supplies are carried at moving average cost. Certain products, principally mined ore stockpiles and bastnaesite concentrate, that are not expected to be processed within the next twelve months, and raw materials and spare parts that are not expected to be consumed within the next twelve months, are classified as non-current.
Inventory cost includes all costs directly attributable to the manufacturing process, including labor, raw materials, and an appropriate portion of production overhead costs, including depreciation and depletion, based on normal capacity of the production facilities. In periods when it is determined that the Company’s production facilities are operating below normal capacity levels, overhead costs are not included in inventory, and are instead directly recorded to “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” or “Depreciation, depletion and amortization” within the Company’s Consolidated Statements of Operations.
The Company evaluates the carrying amount of inventory each reporting period, considering recent market prices, slow-moving items, obsolescence, excess inventory levels and other factors. All inventories are carried at the lower of cost or net realizable value (“NRV”). NRV represents the estimated selling price of the product less reasonably predictable costs of completion, disposal, and transportation. The PPA provides contractual price protection for designated NdPr Products. This ensures the Company will receive at least the price floor for such products. The Company includes future estimated PPA income in the NRV of certain inventories. Write-downs are recognized for the excess of a product’s cost over its NRV. See also Note 5, “Inventories.”
Property, Plant and Equipment: Property, plant and equipment are recorded at cost and depreciated over their useful lives. Expenditures for new property, plant and equipment and improvements that extend the useful life or functionality of the assets are recorded at their cost of acquisition or construction. Depreciation on property, plant and equipment is recognized on a straight-line basis over their estimated useful lives, as follows:
Years
Land improvements
10-25
Buildings and building improvements
10-40
Machinery and equipment
3-20
Assets under construction include costs directly attributable to the construction or development of long-lived assets. These costs may include labor and employee benefits associated with the construction of the asset, site preparation, permitting, engineering and design, installation and assembly, procurement, insurance, legal, initial commissioning, and interest on borrowings to finance the construction of the assets. Depreciation is not recorded on the related assets until they are ready for their intended use. Repair and maintenance costs that do not extend the useful life of an asset are expensed as incurred. Gains and losses arising from the sale or disposal of property, plant and equipment are determined as the difference between the proceeds from sale or disposal and the carrying amount of the asset, and are included, along with demolition costs, in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations.
Property, plant and equipment primarily relate to the Company’s open-pit mine and processing and separations facility at Mountain Pass as well as building and machinery associated with the Company’s Independence Facility, including electrolysis cells, strip casters, and sintering furnaces. In addition to the mine pit, Mountain Pass includes a crusher and mill/flotation plant, mineral recovery and separation plants, tailings processing and storage facilities, product finishing facilities, on-site evaporation ponds, a combined heat and power plant, water treatment plant, a chlor-alkali facility, as well as laboratory facilities to support research and development activities, offices, warehouses and support infrastructure. See also Note 6, “Property, Plant and Equipment.”
Mineral Rights: The Company capitalizes costs for acquiring and leasing mining properties and expenses costs to maintain mineral rights as incurred. Depletion on mineral rights is recognized on a straight-line basis over the estimated remaining useful life of the mine, which was approximately 28 years as of December 31, 2025. The Company determined that the straight-line method of depletion appropriately captures the estimated economic costs of extracting the minerals of the mine across its estimated useful life, and aligns with the benefit obtained from the depletion of the asset consistent with the current mine plan. Mineral rights are classified as a component of “Property, plant and equipment, net” within the Company’s Consolidated Balance Sheets. See also Note 6, “Property, Plant and Equipment.”
PPA Upfront Asset: The PPA is a price floor protection agreement that conveys a contingent right for the Company to receive cash from the DoW and also imposes a contingent obligation for the Company to deliver cash to the DoW in the future as described in Note 3, “Public-Private Partnership with U.S. Department of War.” Given the contractual cash flows, the right to the price floor protection granted by the DoW under the PPA (the “PPA Upfront Asset”) was determined to be a financial instrument. The initially recognized amount of the PPA Upfront Asset results from the difference between the fair value of the other instruments exchanged with the DoW and the cash consideration received from the DoW. The PPA Upfront Asset is presented as “Price protection agreement upfront asset, net” in non-current assets within the Company’s Consolidated Balance Sheets. The Company did not elect to apply the fair value option to the PPA Upfront Asset on a recurring basis. Beginning October 1, 2025, the PPA’s commencement date, the PPA Upfront Asset is being amortized over the Company’s expected pattern of economic benefit from the PPA, with the expense recognized within “Depreciation, depletion and amortization” in the Company’s Consolidated Statements of Operations. Reassessment of the PPA Upfront Asset’s useful life, pattern of economic benefit as well as impairment considerations is consistent with the Company’s existing policies for long-lived assets. See Note 3, “Public-Private Partnership with U.S. Department of War,” for additional information.
Operating Leases: The Company determines if an arrangement is, or contains, a lease at contract inception. In some cases, the Company has determined that its lease arrangements include both lease and non-lease components. The Company has elected to use a practical expedient to account for each separate lease component and its associated non-lease components as a single lease component for the majority of its asset classes. The Company recognizes right-of-use (“ROU”) assets and lease liabilities upon commencement for all leases with a lease term greater than 12 months. The Company has elected to use a practical expedient to not recognize leases with a lease term of 12 months or less in the Consolidated Balance Sheets for all of its asset classes. These short-term leases are expensed on a straight-line basis over the lease term.
ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the commencement date of the lease based on the present value of lease payments over the lease term. When the rate implicit in the lease cannot be readily determined, the Company utilizes its incremental borrowing rate in determining the present value of the future lease payments. Lease liabilities are accreted each period and reduced for payments. The ROU asset also includes other adjustments, such as for the effects of lease prepayments, initial lease costs, or lease incentives received. The lease term may include periods covered by options to extend or terminate the lease when it is either reasonably certain that the Company will exercise a renewal option, or reasonably certain it will not exercise an early termination option. Lease expense is recognized on a straight-line basis over the lease term. Variable lease payments not included in the lease liability are expensed as incurred unless such costs are capitalized as part of another asset (e.g., inventory). Additionally, ROU assets are subject to impairment testing whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. If the carrying amounts of ROU assets exceed their fair value, the excess amount is recognized as an impairment. See also Note 11, “Operating Leases.”
Capitalized Contract Fulfillment Costs: In accordance with ASC Subtopic 340-40, the Company evaluates whether or not certain costs incurred to obtain and fulfill contracts with customers should be capitalized. Capitalized contract fulfillment costs that are not within the scope of another ASC Topic are capitalized if they: (1) relate directly to an existing or specific anticipated contract, (2) generate or enhance resources that will be used to satisfy future performance obligations, and (3) are expected to be recovered. Capitalized costs are presented within “Other non-current assets” within the Company’s Consolidated Balance Sheets and are amortized on a systematic basis that is consistent with the pattern of transfer of the goods or services to which the asset relates. See also Note 11, “Operating Leases.”
Impairment of Long-Lived Assets: Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. In estimating undiscounted cash flows, assets are grouped at the lowest level for which there are identifiable cash flows that are largely independent of undiscounted cash flows from other asset groups. The Company’s estimates of undiscounted cash flows are based on numerous assumptions, and it is possible that actual cash flows may differ significantly from estimates, as actual produced reserves, prices, commodity-based and other costs, and closure costs are each subject to significant risks and uncertainties. The estimated undiscounted cash flows used to assess recoverability of long-lived assets and to measure the fair value of the Company’s operations are derived from current business plans, which are developed using short-term price forecasts reflective of the current price environment and the Company’s projections for long-term average prices. In addition to short- and long-term price assumptions, other assumptions include estimates of production costs; proven and probable mineral reserve estimates, including the timing and cost to develop and produce the reserves; value beyond proven and probable estimates; and estimated future closure costs.
If the carrying amount of the long-lived asset or asset groups is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques, including discounted cash flow models, quoted market values, and third-party independent appraisals, based on the approach the Company believes a market participant would use.
Equity Method Investment: Investments in equity securities are accounted for under the equity method if the Company has the ability to exercise significant influence, but not control, over an investee’s operating and financial policies. Judgment regarding the level of influence includes considering key factors such as the Company’s ownership interest, representation on the board of directors, participation in policy-making decisions and material intra-entity transactions. Under the equity method, an investment’s carrying amount is adjusted for the Company’s share of the investee’s net income or loss (including other comprehensive income or loss), amortization/accretion of certain basis differences (if any), capital contributions to and distributions from an investee, as well as any other-than-temporary impairments.
The Company records its share of an equity method investment’s net income or loss on a one-quarter lag due to the timing of when an investee’s financial statements become available. The Company evaluates material events occurring during the one-quarter lag to determine whether the effects of such events should be reflected or disclosed within the Company’s Consolidated Financial Statements. For intra-entity transactions between the Company and its equity method investee, the Company eliminates its share of profits and losses until realized by the Company or investee. Such elimination is recorded as an adjustment of the carrying amount of the equity method investment. See Note 7, “Equity Method Investment,” for additional information.
Intangible Assets: Indefinite-lived intangible assets are tested annually for impairment, or more frequently if events or changes in circumstances indicate that it is more likely than not that the assets are impaired. If the carrying amounts of the indefinite-lived intangible assets exceed their fair value, the excess amount is recognized as an impairment. Intangible assets that have a definite life are amortized on a straight-line basis over their estimated useful lives to reflect the expected pattern of economic benefits consumed. The Company reviews the carrying amount of its amortizing intangible assets for possible impairment whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. If the carrying amounts of the amortizing intangible assets exceed their fair value, the excess amount is recognized as an impairment. Once an impairment of an intangible asset has been recorded, it cannot be reversed. See also Note 8, “Intangible Assets.”
Deferred Revenue: Contract liabilities, commonly referred to as deferred revenue, represent the Company’s obligation to transfer goods or services to a customer for which the Company has received consideration in advance of such transfer. Deferred revenue decreases as revenue is recognized from the satisfaction of the related performance obligations. Amounts expected to be recognized as revenue during the 12-month period after the balance sheet date are classified as current deferred revenue with the remainder classified as non-current in the Company’s Consolidated Balance Sheets. See Note 16, “Revenue Recognition,” for additional information.
Asset Retirement Obligations: The Company recognizes asset retirement obligations (“ARO”) for estimated costs of legally and contractually required closure, dismantlement, and reclamation activities associated with Mountain Pass. ARO are initially recognized at their estimated fair value in the period in which the obligation originates. Fair value is based on the expected timing of reclamation activities, cash flows to perform activities, amount and uncertainty associated with the cash flows, including adjustments for a market risk premium, and discounted using a credit-adjusted risk-free rate. The liability is accreted over time through periodic charges to earnings and reduced as reclamation activities occur with differences between estimated and actual amounts recognized as adjustments to operating expenses. Accretion of ARO is included in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations.
Subsequent increments in expected undiscounted cash flows are measured at their discounted values using updated estimates of the Company’s credit-adjusted risk-free rate applied to the increment only. Subsequent decrements in expected undiscounted cash flows are reduced based on the weighted-average credit-adjusted risk-free rate associated with the obligation. When increments and decrements are caused by a change in the estimated timing of settlement, the Company treats the increase in cash flows in the year of the updated estimate as an increment and the decrease in cash flows in the original year as a decrement. Associated asset retirement costs, including the effect of increments and decrements, are recognized as adjustments to the related asset’s carrying amount and depreciated over the related asset’s remaining useful life. If a decrement is greater than the carrying amount of the related asset, the difference is recognized as a reduction to depreciation expense. See also Note 9, “Asset Retirement and Environmental Obligations.”
Environmental Obligations: The Company has certain environmental remediation obligations that primarily relate to groundwater monitoring activities. Estimated remediation costs are accrued based on management’s best estimate at the end of each reporting period of the costs expected to be incurred to settle the obligation when those amounts are probable and estimable. If the cost can only be estimated as a range of possible amounts with no point in the range being more likely, then the minimum of the range is accrued. Such cost estimates may include ongoing care, maintenance and monitoring costs associated with remediation activities. Changes in remediation estimates are reflected in earnings in the period the estimate is revised. Remediation costs included in environmental obligations are discounted to their present value when payments are readily estimable, and are discounted using a risk-free rate, which the Company derives from U.S. Treasury yields. Accretion of environmental obligations is included in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations. See also Note 9, “Asset Retirement and Environmental Obligations.”
Convertible Debt and Embedded Derivatives: The Company accounts for its convertible debt in accordance with ASC Subtopic 470-20, “Debt with Conversion and Other Options” (“ASC 470-20”), whereby the convertible instrument is initially accounted for as a single unit of account, unless it contains a derivative that must be bifurcated from the host contract in accordance with ASC Topic 815, “Derivatives and Hedging” (“ASC 815”) or the substantial premium model in ASC Subtopic 470-20 applies. When it is determined that an embedded derivative is required to be bifurcated, the Company recognizes the bifurcated embedded derivative, measured at fair value, as a separate derivative asset or liability upon initial recognition and in subsequent periods at fair value with changes in fair value included in profit or loss each reporting period. Changes in the fair value each reporting period are included in “Other income, net” within the Company’s Consolidated Statements of Operations. Where the substantial premium model applies, the premium is recorded in “Additional paid-in capital” in “Stockholders’ equity” within the Company’s Consolidated Balance Sheets. See also Note 10, “Debt Obligations.”
Capped Call Options: The Company’s Capped Call Options cover the aggregate number of shares of its common stock that initially underlie the 2030 Notes (as such terms are defined in Note 10, “Debt Obligations”) that were issued in March 2024, and generally reduce potential dilution to the Company’s common stock upon the conversion of the 2030 Notes and/or offset any cash payments the Company may make in excess of the principal amount of the converted 2030 Notes, as the case may be, with such reduction and/or offset subject to a cap, based on the cap price of the Capped Call Options.
The Company determined that the Capped Call Options meet the definition of a freestanding derivative under ASC 815 but are not required to be separately accounted for as a derivative as they meet the indexation and equity classification scope exception outlined in ASC 815. Accordingly, the Company recognized the cash paid to enter into the Capped Call Options contract by recording an entry to “Additional paid-in capital” in “Stockholders’ equity” within the Company’s Consolidated Balance Sheets. The Capped Call Options will not be remeasured each reporting period. See Note 10, “Debt Obligations,” and Note 18, “Stockholders’ Equity and Stock-Based Compensation,” for additional information.
Debt Discount and Debt Issuance Costs: Debt discount represents the difference between the net proceeds received and the debt’s fair value at the time of issuance. Debt issuance costs include incremental third-party costs directly related to the debt issuance. For debt instruments other than the Company’s Revolving Credit Facility (as defined in Note 10, “Debt Obligations”), debt discount and debt issuance costs are recorded as a direct reduction of the carrying amount of the associated debt instrument and are amortized to interest expense using the effective interest method over the contractual term of the underlying indebtedness. Debt issuance costs related to the Company’s Revolving Credit Facility are recorded in “Other non-current assets” within the Company’s Consolidated Balance Sheets and are amortized to interest expense on a straight-line basis over the term of the Revolving Credit Facility arrangement. See Note 3, “Public-Private Partnership with U.S. Department of War,” and Note 10, “Debt Obligations,” for additional details.
Commitments and Contingencies: Liabilities for loss contingencies arising from claims, assessments, litigation, fines and penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. If a loss contingency is not probable or reasonably estimable, disclosure of the contingency and estimated range of loss, if determinable, is made in the financial statements when it is at least reasonably possible that a material loss could be
incurred. Legal costs incurred in connection with loss contingencies are expensed as incurred. See also Note 13, “Commitments and Contingencies.”
Series A Preferred Stock: The Company’s Series A Preferred Stock is classified as redeemable preferred stock (i.e., temporary equity) outside of stockholders’ equity within the Company’s Consolidated Balance Sheets due to certain redemption rights not solely within the Company’s control. The purpose of this classification is to convey that such a security may not be permanently part of equity and could result in a demand for cash, securities or other assets of the entity in the future. All financial instruments are evaluated for embedded derivative features by analyzing each feature against the nature of the host instrument (e.g., more equity-like or debt-like). Features identified as freestanding instruments or bifurcated embedded derivatives that are material are recognized separately as a derivative asset or liability. The Company evaluated the Series A Preferred Stock and determined that its nature is that of an equity-host with no embedded derivatives requiring bifurcation. The Company initially recognized the Series A Preferred Stock at its relative fair value, net of allocated issuance costs.
At each reporting period, the Company reassesses whether the Series A Preferred Stock is (i) currently redeemable or (ii) probable of becoming redeemable in the future. If the instrument meets either criterion, the Company will adjust the carrying amount to the estimated maximum redemption value (i.e., the redemption price). As of December 31, 2025, the Series A Preferred Stock was not redeemable, nor probable of becoming redeemable in the future. As such, the carrying amount of the Series A Preferred Stock was not adjusted to the maximum redemption value. See Note 14, “Redeemable Preferred Stock,” for additional details.
Warrants: The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms. The assessment considers whether the warrants are freestanding financial instruments, meet the definition of a liability, and whether the warrants meet all of the requirements for equity classification, including whether the warrants are indexed to the Company’s own common stock. The Company analyzed the classification of its outstanding Warrant as of the date of issuance and as of December 31, 2025, and determined that such instrument met the criteria for equity classification. See Note 18, “Stockholders’ Equity and Stock-Based Compensation,” for additional information.
Treasury Stock: Treasury stock represents shares of the Company’s common stock that have been reacquired after having been issued and is accounted for under the cost method. Treasury stock is excluded from the Company’s outstanding shares and recorded as a reduction of “Stockholders’ equity” within the Company’s Consolidated Balance Sheets, unless the repurchased shares are immediately retired. Incremental direct costs to purchase treasury stock, such as excise taxes and commission fees, are included in the cost of the shares acquired. See also Note 18, “Stockholders’ Equity and Stock-Based Compensation.”
Revenue Recognition: The Company’s revenue comes from sales of rare earth products produced at Mountain Pass and sales of magnetic precursor products, including NdPr metal, produced at the Independence Facility. The Company recognizes revenue for the amount it expects to receive, which may include variable consideration and be reduced for amounts payable to a customer. Variable consideration is included in the Company’s expected sales price to the extent it is probable there will not be a significant reversal of previously recognized revenue. Revenue is recognized when control of the promised products is transferred to the customer, which generally occurs at the point in time the products are delivered to the agreed-upon shipping point. To determine when control of the products transfers to a customer, the Company evaluates the point in time the customer bears the risk of loss and has the ability to direct the use of and obtain substantially all of the remaining benefits from the products. Revenue from product sales is recorded net of taxes collected from customers that are remitted to governmental authorities.
Periodically, the Company receives requests from its customers to temporarily hold purchased products at the Company’s facilities under a bill-and-hold arrangement. The Company recognizes revenue under these arrangements only when there is a substantive reason for the agreement, the ordered goods are identified separately as belonging to the customer, the goods are currently ready for physical transfer to the customer, and the Company does not have the ability to use the product or to direct it to another customer. Assuming these criteria are met, revenue is recognized at the point in time control of the product transfers to the customer, which may be upon completion of product manufacture or delivery to an agreed location. See also Note 16, “Revenue Recognition.”
Price Protection Agreement Income or Expense: On a quarterly basis, beginning on the PPA’s commencement date and throughout the PPA’s 10-year term, the Company will have the right to receive cash from or an obligation to deliver cash to the DoW. The Company recognizes its rights or obligations as price protection agreement income or expense within the Company’s Consolidated Statements of Operations in the period in which the events giving rise to the right or obligation occur. Each quarterly period represents a distinct contractual period for which amounts receivable or payable are recognized as earned or incurred, respectively. See Note 3, “Public-Private Partnership with U.S. Department of War,” for additional details.
Government Grants: Government grants represent benefits provided by federal, state, or local governments that are not subject to the scope of ASC Topic 740, “Income Taxes” (“ASC 740”). Government grants are initially estimated and recognized when there is reasonable assurance the conditions of the grant will be met, and the grant will be received. When a grant is related to the purchase or construction of a long-lived asset (considered asset-based grants), the funds received are recorded as a reduction to the related asset’s carrying amount, thereby reducing future depreciation expense. Alternatively, when a grant is related to an expense item (considered income-based grants), it is recognized as a reduction of expense to which the grant activity relates over the periods necessary to match the grant on a systematic basis to the costs that it is intended to compensate. The effect of a change in estimate is recognized in the period in which management concludes that it is no longer reasonably assured that (i) all of the grant conditions will be met or (ii) a portion of the grant will be received. See also Note 17, “Government Grants.”
Stock-Based Compensation: From time to time, the Company grants to its employees and directors certain stock-based awards, which are comprised of the following types: (i) Stock Awards (as defined in Note 18, “Stockholders’ Equity and Stock-Based Compensation”), (ii) market-based performance stock units (“market-based PSUs”) and (iii) performance-based performance stock units (“performance-based PSUs”). The cost of employee services received in exchange for an award of equity instruments is based on the grant-date fair value of the award. The Company accounts for forfeitures in the period in which they occur based on actual forfeitures.
Stock Awards contain service conditions, and their fair value equals the product of the Company’s stock price on the date of grant and the number of Stock Awards granted. Compensation cost for Stock Awards with graded vesting schedules is recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award were, in substance, multiple awards, which results in accelerated recognition of compensation cost.
Market-based PSUs include service and market conditions, and their fair value is determined using a Monte Carlo simulation technique. The Monte Carlo simulation requires the use of inputs and assumptions such as the grant-date closing stock price, expected volatility, correlation coefficient to relevant peer groups or indices, risk-free interest rate and dividend yield. Compensation cost for market-based PSUs with cliff vesting schedules is recognized on a straight-line basis over the requisite service period. Compensation cost for these awards is not adjusted based on the actual achievement of the market-based performance goals.
Performance-based PSUs include service and performance conditions, and their fair value equals the product of the Company’s stock price on the date of grant and the number of awards granted. Compensation cost for performance-based PSUs with cliff vesting schedules is recognized on a straight-line basis over the requisite service period if it is probable that a performance condition will be achieved. No compensation cost will be recognized for a performance condition that is not probable of being achieved. The Company re-evaluates at the end of each reporting period whether or not a performance condition is probable of being achieved. If, based on this re-evaluation, the Company estimates an increase in overall compensation cost, then the Company will recognize a cumulative catch-up of compensation cost in the period of the re-evaluation. Alternatively, if the Company estimates a decrease in overall compensation cost, the Company will not reverse compensation cost already recognized until achievement of the performance condition is estimated to be improbable. See also Note 18, “Stockholders’ Equity and Stock-Based Compensation,” for additional information.
Start-up Costs: Costs associated with restarting an existing facility or commissioning a new facility, circuit or process of the Company’s production, manufacturing, or separations facilities prior to the achievement of commercial production, that do not qualify for capitalization, are expensed as incurred and considered start-up costs. Such costs may include certain salaries and wages, outside services, parts, training, and utilities, among other items, used or consumed directly in these start-up activities.
Earnings or Loss per Common Share: Net income or loss attributable to common stock is computed using the two-class method when shares are issued that meet the definition of participating securities. The Company’s Series A Preferred Stock is a participating security because these shares contractually entitle their holders to potentially participate in dividends by way of the Special Payment (as defined and further described in Note 14, “Redeemable Preferred Stock”), but do not contractually require their holders to participate in the Company’s losses.
The two-class method is an earnings allocation formula that requires undistributed earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. During the periods when there is a net loss, no amounts of undistributed losses are allocated to the Company’s participating securities.
Basic earnings or loss per common share is computed by dividing net income or loss attributable to common stock by the weighted-average number of common shares outstanding during the period.
Diluted earnings or loss per common share is computed by dividing net income or loss attributable to common stock (the numerator) by the weighted-average number of common shares outstanding during the period (the denominator) using the treasury stock method, the if-converted method, or the two-class method, as applicable. The numerator is adjusted for the effects of changes in income available to common stock that arise from the assumed conversion of dilutive convertible securities. The denominator is adjusted for the effects of dilutive potential common shares outstanding.
Income Taxes: The Company accounts for income taxes using the balance sheet method, recognizing certain temporary differences between the book basis of the liabilities and assets and the related income tax basis for such liabilities and assets. This method generates either a net deferred tax liability or asset for the Company, as measured by the statutory tax rates in effect. The Company derives a deferred tax expense or benefit by recording the change in either the net deferred tax liability or asset balance for the year. The Company’s policy, if it were to have uncertain tax positions, is to recognize interest and/or penalties related to unrecognized tax benefits as part of its income tax expense. See also Note 12, “Income Taxes.”
Investment Tax Credits: An investment tax credit (“ITC”) represents a benefit provided by federal, state, or local governments to encourage an entity to invest in specific types of assets. An ITC is commonly calculated as a percentage of the investment cost of a qualifying asset and may be subject to the scope of ASC 740. The accounting for an ITC may depend upon certain factors, including whether or not the ITC is refundable and/or transferable. The Company elected to account for its nonrefundable, transferable ITCs under ASC 740. This type of ITC is initially estimated and recognized when the Company places into service a qualifying asset and determines that it will more-likely-than-not comply with the requirements to receive the ITC. Additionally, the Company elected to account for these ITCs under the deferral method whereby the Company will initially record such ITC as a deferred liability and subsequently recognize the ITC in the income statement as a reduction to income tax expense over the useful lives of the qualifying assets. As a result of the deferral method, the Company also elected to recognize immediately in income tax expense the deferred tax effect, net of any valuation allowance, as a result of such transaction. See also Note 12, “Income Taxes.”
Valuation of Deferred Tax Assets: The Company’s deferred tax assets include certain future tax benefits. The Company records a valuation allowance against any portion of those deferred tax assets when it believes, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax asset will not be realized. The Company reviews the likelihood that the benefit of the deferred tax assets will be realized and the need for valuation allowances on a quarterly basis.
Certain categories of evidence carry more weight in the analysis than others based upon the extent to which the evidence may be objectively verified. The Company looks to the nature and severity of cumulative pretax losses (if any) in the current three-year period ending on the evaluation date, recent pretax losses and/or expectations of future pretax losses. Other factors considered in the determination of the probability of the realization of the deferred tax assets include, but are not limited to: earnings history; projected future financial and taxable income based upon existing reserves and long-term estimates of commodity prices; the duration of statutory carry forward periods; prudent and feasible tax planning strategies readily available that may alter the timing of reversal of the temporary difference; nature of temporary differences and predictability of reversal patterns of existing temporary differences; and the sensitivity of future forecasted results to commodity prices and other factors.
Concluding that a valuation allowance is not required is difficult when there is significant negative evidence which is objective and verifiable, such as cumulative losses in recent years. However, recent cumulative losses are not solely determinative of the need for a valuation allowance. The Company also considers all other available positive and negative evidence in its analysis. See also Note 12, “Income Taxes.”
Recently Issued Accounting Pronouncements Not Yet Adopted: Other than those listed below, there were no accounting pronouncements issued during the year ended December 31, 2025, that had or would be expected to have a material impact on the Company’s Consolidated Financial Statements and accompanying notes.
In December 2025, the FASB issued ASU No. 2025-10, “Government Grants—Accounting for Government Grants Received by Business Entities” (“ASU 2025-10”), to establish authoritative GAAP guidance for the recognition, measurement, and presentation of government grants received by business entities. The amendments define government grants, distinguish between grants related to assets and income, and provide criteria for when grants are recognized. Entities may elect either a deferred income approach or a cost accumulation approach for asset-related grants, while income-related grants are recognized systematically over the periods of related expenses. Additionally, ASU 2025-10 prescribes presentation options and requires disclosures about the nature, terms, and accounting policies for grants. ASU 2025-10 is effective for the Company’s fiscal years beginning after December 15, 2027, and may be applied prospectively or retrospectively. The Company is currently evaluating the effect of adopting ASU 2025-10 on its financial statements and disclosures.
In November 2024, the FASB issued ASU No. 2024-03, “Income Statement—Reporting Comprehensive Income Expense Disaggregation Disclosures” (“ASU 2024-03”), which amends ASC Topic 220, “Comprehensive Income,” to enhance the disclosure of expense information in the notes to the financial statements. ASU 2024-03 requires public business entities to disaggregate specified income statement expenses, such as purchases of inventory, employee compensation, depreciation, amortization, and depletion into detailed categories presented in a tabular format. Additionally, ASU 2024-03 mandates qualitative descriptions for expenses not separately disaggregated and annual disclosure of selling expenses and their definitions. ASU 2024-03 is effective for the Company’s fiscal years beginning after December 15, 2026, and interim periods beginning after December 15, 2027, and may be applied prospectively or retrospectively. The Company is currently evaluating the effect of adopting ASU 2024-03 on its disclosures.
In November 2024, the FASB issued ASU No. 2024-04, “Induced Conversions of Convertible Debt Instruments” (“ASU 2024-04”), which enhances guidance in ASC Topic 470, “Debt,” to improve consistency and relevance in accounting for induced conversions of convertible debt instruments. Specifically, ASU 2024-04 clarifies criteria for when settlements should be treated as induced conversions, requiring that inducement offers preserve the form and amount of consideration issuable under original conversion terms. ASU 2024-04 is effective for the Company’s fiscal years and interim periods within those fiscal years beginning after December 15, 2025, with early adoption permitted, and may be applied prospectively or retrospectively. The Company is currently evaluating the effect of adopting ASU 2024-04 on its financial statements and disclosures.
Reclassifications: Certain amounts in prior periods have been reclassified to conform to the current year presentation.
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR
 12 Months Ended
Dec. 31, 2025
Government Assistance [Abstract]  
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR
On July 9, 2025, the Company entered into the DoW Transaction Agreements, whereby the Company agreed to use its reasonable best efforts to (i) construct the 10X Facility, which will produce sintered NdFeB permanent magnets, (ii) extend HREE refining capability at Mountain Pass to include the separation of samarium oxide, (iii) recommission the chlor-alkali facilities at Mountain Pass and (iv) expand capacity at the Independence Facility to a projected 3,000 MTs of magnets annually. The Company also agreed to use up to $600 million of its existing cash to fund these projects. Additionally, the DoW Transactions consist of a comprehensive, long-term package of commitments from the DoW, including pricing support, a long-term offtake agreement and certain financing arrangements. Key terms include the following:
Pricing & Supply Commitments
Price Protection Agreement: The PPA establishes a price floor for the Company’s NdPr products (e.g., concentrate, oxide and metal) (collectively, “NdPr Products”), commencing on October 1, 2025, and continuing for approximately ten years through December 31, 2035. Throughout the PPA’s term, the Company will have the right to receive cash from, or the obligation to deliver cash to, the DoW based on (i) its designation of NdPr Products produced and/or sold (the “NdPr Designation”) and (ii) the Benchmark Quarterly Average Volume Weighted Price (as defined in the PPA).
At the conclusion of each quarter, the Company may elect, at its option, any of the following NdPr Designations (without duplication):
•“Stockpile” represents produced, but not yet sold NdPr Product,
•“Affiliate sales” represents internally sold NdPr Product, such as sales from the Materials segment to the Magnetics segment, or
•“Third party sales” represents externally sold NdPr Product.
On a quarterly basis, the DoW will pay the Company an amount per kilogram (“kg”) equivalent of NdPr Products equal to the shortfall between $110 and the Benchmark Quarterly Average Volume Weighted Price. Once the 10X Facility reaches full production capacity (the “Production Milestone Date”), and the Benchmark Quarterly Average Volume Weighted Price exceeds $110, the Company will pay the DoW 30% of the amount by which the Benchmark Quarterly Average Volume Weighted Price exceeds $110.
For the year ended December 31, 2025, the Company recognized $51.0 million in “Price protection agreement income” within the Company’s Consolidated Statements of Operations, and accrued this amount within the Consolidated Balance Sheets in “Other receivables.” The income pertains primarily to NdPr Product contained in stockpiled concentrate, which remains in “Inventories” within the Consolidated Balance Sheets, and third-party sales of NdPr Product.
DoW Offtake Agreement: The Company entered into a magnet offtake agreement with the DoW (the “DoW Offtake Agreement”), pursuant to which the Company will sell to the DoW the entire amount of magnets produced at the 10X Facility;
provided, however, that at the DoW’s request, or at the Company’s request and with the DoW’s consent, the Company may sell up to 100% of magnet production to other third-party customers. The DoW will acquire the magnets at a price equal to their production costs (as defined in the DoW Offtake Agreement), plus the guaranteed EBITDA discussed below. The DoW Offtake Agreement’s term will continue through 10 years from the date at which the 10X Facility begins operations and is capable of producing any quantity of magnets (the “Commercial Operation Date”). Given the DoW’s right to substantially all of the economic benefits of the 10X Facility and its ability to direct the use of the 10X Facility, the DoW Offtake Agreement contains a lease for the 10X Facility. See Note 11, “Operating Leases,” for additional information.
In accordance with the DoW Offtake Agreement, the DoW guaranteed that the 10X Facility will generate at least $140 million of EBITDA (as defined in the DoW Offtake Agreement) on an annual basis after the Production Milestone Date, adjusted annually in each calendar year following 2025 for inflation at a rate equal to 2% (the “Threshold EBITDA Amount”). Between the Commercial Operation Date and the Production Milestone Date, the Company is entitled to a proportion of the Threshold EBITDA Amount based on demonstrated capacity levels. The DoW will make quarterly payments to the Company in an amount equal to 25% of the Threshold EBITDA Amount, subject to annual true up.
Commencing on the Production Milestone Date, if the Company sells magnets to third-party customers, the DoW will be entitled to receive for each calendar year (i) the first $30 million of EBITDA attributable to the 10X Facility that exceeds the Threshold EBITDA Amount (the “Initial Excess Amount”) and thereafter (ii) 50% of the EBITDA attributable to the 10X Facility that exceeds the Initial Excess Amount.
Under the DoW Offtake Agreement, before the Commercial Operation Date, the Company is entitled to receive reimbursement from the DoW for certain incremental costs incurred by the Company in connection with engineering, development and start-up of the 10X Facility and for designing magnets to the DoW’s specifications (to the extent such costs are not capitalizable as 10X Facility construction costs), with such payments being capped at $30 million in any calendar year. See Note 11, “Operating Leases” for further discussion regarding these costs.
The DoW Transaction Agreements also provide that the DoW will assist the Company in procuring HREE feedstock required for magnet production at the 10X Facility over the duration of the DoW Offtake Agreement. Working capital costs associated with stockpiling or forward purchasing of HREE are also reimbursable by the DoW, with no annual cap, through the Commercial Operation Date.
Financings
Series A Preferred Stock: The Company issued 400,000 shares of newly designated Series A Cumulative Perpetual Convertible Preferred Stock, par value $0.0001 per share (the “Series A Preferred Stock”) to the DoW for cash consideration of $400.0 million. At the election of the DoW, the Series A Preferred Stock is convertible at any time into 13,320,013 shares of the Company’s common stock at an initial conversion price of $30.03 per share, subject to customary anti-dilution adjustments. See Note 14, “Redeemable Preferred Stock,” for additional details.
Warrant: The Company issued a warrant (the “Warrant”) to the DoW, exercisable at any time for a period of ten years for up to 11,201,659 shares of the Company’s common stock, at an initial exercise price of $30.03 per share, subject to customary anti-dilution adjustments. See Note 18, “Stockholders’ Equity and Stock-Based Compensation,” for additional details.
In the aggregate, the common stock into which the Series A Preferred Stock is initially convertible and for which the Warrant is initially exercisable collectively represented 15% of the issued and outstanding shares of the Company’s common stock as of July 9, 2025, without giving effect to the issuance of such shares.
Commitment Letter for Facility Construction: In connection with the DoW Transaction Agreements, the Company obtained a commitment letter (the “Commitment Letter”) from JPMorgan Chase Funding Inc. and Goldman Sachs Bank USA (along with their affiliates, the “Banks”), pursuant to which the Banks agreed to provide committed secured financing in an amount equal to, in the aggregate, at least $1 billion. The Commitment Letter expired undrawn on its own terms on August 26, 2025, as it was reduced on a dollar-for-dollar basis upon the Offering (as defined in Note 18, “Stockholders’ Equity and Stock-Based Compensation”) and the Company’s execution of the Revolving Credit Facility (as defined in Note 10, “Debt Obligations”). In connection with the issuance of the Commitment Letter, the Company incurred $7.4 million of nonrefundable commitment and structuring fees which were recorded as an expense in “Advanced projects and development” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2025.
Samarium Project Loan: In August 2025, the Company issued a $150.0 million unsecured promissory note to the DoW with a 12-year term, maturing on August 1, 2037 (the “Samarium Project Loan”). The Samarium Project Loan was issued for
the purpose of the Company extending HREE refining capability at Mountain Pass to include separation of samarium oxide. See Note 10, “Debt Obligations,” for additional details.
Consideration Exchanged and Allocation
The Company issued the Series A Preferred Stock, Warrant, and Samarium Project Loan (the “Issued Instruments”), which had an aggregate fair value of $768.6 million, in exchange for cash and non-cash consideration. Total cash consideration was $550.0 million, consisting of $400.0 million from the issuance of the Series A Preferred Stock and $150.0 million from the issuance of the Samarium Project Loan. The difference between the fair value of the Issued Instruments and the cash consideration received was $218.6 million, which represents the value of the price protection rights provided under the PPA. As a result, the Company received total consideration of $768.6 million.
The Company allocated the total consideration received among the Issued Instruments, considering whether the instruments are measured at fair value on a recurring basis. As none of the Issued Instruments will be measured at fair value on a recurring basis, the $768.6 million was allocated on a relative fair value basis to the Issued Instruments. The Company incurred $11.3 million of capitalizable transaction costs, which were allocated to the Issued Instruments and the PPA on a proportional basis. The following table presents the initially recognized amounts for the DoW Transactions:
(in thousands)Measured ValueAllocated Transaction CostsRecognized Amount
Consideration received:
Cash$550,000 $— $550,000 
PPA Upfront Asset218,600 2,502 221,102 
Total consideration received$768,600 $2,502 $771,102 
Consideration given:
Series A Preferred Stock$418,400 $(4,789)$413,611 
Warrant264,200 (3,024)261,176 
Samarium Project Loan86,000 (985)85,015 
Total consideration given$768,600 $(8,798)$759,802 
The total cash and non-cash consideration received in exchange for the Issued Instruments was allocated on a relative fair value basis as included in the table below. The non-cash consideration amounts are disclosed as a non-cash investing and financing activity in Note 23, “Supplemental Cash Flow Information.”
(in thousands)Cash ConsiderationNon-cash ConsiderationMeasured Value
Issued Instruments:
Series A Preferred Stock$299,402 $118,998 $418,400 
Warrant189,058 75,142 264,200 
Samarium Project Loan61,540 24,460 86,000 
Total consideration received for Issued Instruments$550,000 $218,600 $768,600 
The PPA Upfront Asset within the Company’s Consolidated Balance Sheets consisted of the following:
December 31,
(in thousands)20252024
PPA Upfront Asset$221,102 $— 
Less: Accumulated amortization (11,434)— 
PPA Upfront Asset, net
$209,668 $— 
Amortization expense related to the PPA Upfront Asset, which was included in “Depreciation, depletion and amortization” within the Company’s Consolidated Statements of Operations, was $11.4 million for the year ended December 31, 2025. No such amount was recognized for the years ended December 31, 2024, and 2023. The remaining useful life of the PPA Upfront
Asset was 10 years as of December 31, 2025. No impairment charges were recorded during the year ended December 31, 2025. As of December 31, 2025, the carrying amount of the PPA Upfront Asset approximated its fair value.
The following table presents the estimated amortization expense for the PPA Upfront Asset as of December 31, 2025:
(in thousands)
Period:
2026$43,539 
202741,142 
202838,246 
202932,898 
203021,498 
Thereafter32,345 
Total$209,668 
v3.25.4
CASH, CASH EQUIVALENTS AND INVESTMENTS
 12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
CASH, CASH EQUIVALENTS AND INVESTMENTS CASH, CASH EQUIVALENTS AND INVESTMENTS
The following table presents the Company’s cash, cash equivalents and short-term investments:
December 31, 2025December 31, 2024
(in thousands)Amortized Cost BasisUnrealized GainsUnrealized LossesEstimated Fair ValueAmortized Cost BasisUnrealized GainsUnrealized LossesEstimated Fair Value
Cash:
Demand deposits$16,536 $— $— $16,536 $1,889 $— $— $1,889 
Cash equivalents:
Money market funds748,322 — — 748,322 164,477 — — 164,477 
U.S. Treasury securities334,339 59 — 334,398 86,320 17 — 86,337 
Commercial paper48,762 7 — 48,769 29,731 8 — 29,739 
Certificates of deposit17,985 1 — 17,986 — — — — 
Total cash equivalents1,149,408 67 — 1,149,475 280,528 25 — 280,553 
Total cash and equivalents1,165,944 67 — 1,166,011 282,417 25 — 282,442 
Short-term investments:
U.S. agency securities— — — — 2,240 — — 2,240 
U.S. Treasury securities636,214 367 — 636,581 544,410 222 (12)544,620 
Commercial paper
21,767 4 — 21,771 16,661 6 — 16,667 
Certificates of deposit5,923 — — 5,923 4,897 2 — 4,899 
Total short-term investments663,904 371 — 664,275 568,208 230 (12)568,426 
Total cash, cash equivalents and short-term investments$1,829,848 $438 $— $1,830,286 $850,625 $255 $(12)$850,868 
The Company does not intend to sell, nor is it more likely than not that the Company will be required to sell, any investments in unrealized loss positions before recovery of their amortized cost basis. The Company did not recognize any credit losses related to its available-for-sale investments during the years ended December 31, 2025, 2024 and 2023. None of the available-for-sale investments held as of December 31, 2025, were in a continuous unrealized loss position for greater than 12 months and the unrealized losses and the related risk of expected credit losses were not material. The Company’s gross realized gains and losses were not material for the years ended December 31, 2025, 2024 and 2023.
The Company’s interest and investment income, which is included in “Other income, net” within the Company’s Consolidated Statements of Operations, was as follows:
For the year ended December 31,
(in thousands)202520242023
Interest and investment income(1)
$52,015 $47,114 $55,637 
(1)Includes interest and investment income on the Company’s available-for-sale securities and other money market funds.
As of December 31, 2025, all outstanding available-for-sale investments had contractual maturities within one year and aggregated to a fair value of $1,065.4 million.
v3.25.4
INVENTORIES
 12 Months Ended
Dec. 31, 2025
Inventory Disclosure [Abstract]  
INVENTORIES INVENTORIES
The Company’s inventories consisted of the following:
December 31,
(in thousands)20252024
Raw materials and supplies, including spare parts
$56,491 $48,400 
Mined ore stockpiles
23,795 31,142 
Work in process
51,652 14,447 
Finished goods
39,622 13,916 
Total current inventories171,560 107,905 
Add: Non-current portion(1)
80,539 19,031 
Total inventories$252,099 $126,936 
(1)Primarily represents stockpiles of mined ore, bastnaesite concentrate and lanthanum that are not expected to be processed or consumed within the next 12 months. The ore, concentrate and lanthanum amounts were $24.1 million, $31.7 million and $10.5 million as of December 31, 2025, respectively, and $12.3 million, zero and zero as of December 31, 2024, respectively.
During the years ended December 31, 2025, 2024 and 2023, the Company determined that the cost of a portion of its inventory exceeded its NRV, resulting in write-downs on certain inventories of $3.0 million, $21.5 million and $2.3 million, respectively, which were included in “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Consolidated Statements of Operations. The write-downs were largely attributable to elevated carrying costs of the Company’s production of separated products given the respective stages of ramping the midstream operations facilities to normalized production levels.
v3.25.4
PROPERTY, PLANT AND EQUIPMENT
 12 Months Ended
Dec. 31, 2025
Property, Plant and Equipment [Abstract]  
PROPERTY, PLANT AND EQUIPMENT PROPERTY, PLANT AND EQUIPMENT
The Company’s property, plant and equipment consisted of the following:
December 31,
(in thousands)20252024
Land and land improvements$43,422 $42,789 
Buildings and building improvements101,564 96,961 
Machinery and equipment756,202 662,333 
Assets under construction302,935 202,544 
Mineral rights438,395 438,395 
Property, plant and equipment, gross1,642,518 1,443,022 
Less: Accumulated depreciation and depletion(272,701)(191,526)
Property, plant and equipment, net$1,369,817 $1,251,496 
Additions to Property, Plant and Equipment: The Company capitalized expenditures related to property, plant and equipment of $206.4 million, $169.7 million and $280.0 million for the years ended December 31, 2025, 2024 and 2023, respectively, including amounts not yet paid (see Note 23, “Supplemental Cash Flow Information”) and excluding equipment purchased with promissory notes (see Note 10, “Debt Obligations”). The capitalized expenditures related primarily to buildings and building improvements, machinery, equipment, and assets under construction to support the Company’s Independence
Facility, as well as various projects at Mountain Pass, including the HREE Facility (as defined in Note 17, “Government Grants”) and chlor-alkali facilities. Capitalized expenditures for the year ended December 31, 2023, also included assets under construction to support the commissioning of the Company’s midstream operations.
The Company’s depreciation and depletion expense, net of amounts capitalized into inventories, was as follows:
For the year ended December 31,
(in thousands)202520242023
Depreciation expense
$69,587 $63,558 $43,998 
Depletion expense
$6,724 $13,036 $11,067 
The Company recognized $5.5 million of demolition costs for the year ended December 31, 2023, which are included in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations, incurred in connection with demolishing and removing certain old facilities from the Mountain Pass site that were never used in the Company’s operations. There were no property, plant and equipment impairments recognized for the years ended December 31, 2025, 2024 and 2023. For information on the Company’s asset-based government grants, which impact the carrying amount of the Company’s property, plant and equipment, see Note 17, “Government Grants.”
v3.25.4
EQUITY METHOD INVESTMENT
 12 Months Ended
Dec. 31, 2025
Equity Method Investments and Joint Ventures [Abstract]  
EQUITY METHOD INVESTMENT EQUITY METHOD INVESTMENT
The Company’s equity method investment balance, which was included in “Other non-current assets” within the Company’s Consolidated Balance Sheets, was zero and $9.1 million, as of December 31, 2025 and 2024, respectively, and pertained to the Company’s 49% equity interest in VREX Holdco Pte. Ltd. (“VREX Holdco”). VREX Holdco wholly owns Vietnam Rare Earth Company Limited (“VREX”), which owns and operates a metal processing plant and related facilities in Vietnam. At the time of the initial investment, the Company determined that VREX Holdco was a variable interest entity, but that the Company was not the primary beneficiary. Consequently, the Company did not consolidate VREX Holdco, and instead, accounted for its investment in VREX Holdco under the equity method of accounting as it had the ability to exercise significant influence, but not control, over VREX Holdco’s operating and financial policies.
In May 2025, the Company sold its 49% interest in VREX Holdco back to VREX Holdco in exchange for a cash payment of $9.7 million. Upon the sale, the Company derecognized its VREX Holdco equity method investment carrying amount and recorded a gain of $1.3 million for the difference between the selling price and the investment’s carrying amount; the gain was included in “Other income, net” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2025. No impairment charges were recorded during the years ended December 31, 2025, 2024 and 2023.
The Company’s share of VREX Holdco’s net loss, which was included in “Other income, net” within the Company’s Consolidated Statements of Operations, was not material for the years ended December 31, 2025 and 2024. No such amount was recognized for the year ended December 31, 2023.
v3.25.4
INTANGIBLE ASSETS
 12 Months Ended
Dec. 31, 2025
Goodwill and Intangible Assets Disclosure [Abstract]  
INTANGIBLE ASSETS INTANGIBLE ASSETS
The Company’s intangible assets are included in “Other non-current assets” within the Company’s Consolidated Balance Sheets and consisted of the following:
December 31,
(in thousands)20252024
Intangible assets with definite lives:
Patent and intellectual property license$8,963 $8,963 
Less: Accumulated amortization(2,788)(1,593)
Intangible assets, net$6,175 $7,370 
In August 2023, the Company acquired a license to use patented technology, technical know-how, and other intellectual property pertaining to the development and manufacturing of magnetic products. Pursuant to the terms of the agreement to acquire the license, 152,504 shares were issued immediately, and 43,573 shares were issued during both the years ended December 31, 2025 and 2024, corresponding to the first and second anniversaries of the acquisition date, respectively. Furthermore, an additional 43,573 and 152,506 shares are due to be issued on the third and fourth anniversaries of the acquisition date, respectively.
Amortization expense related to intangible assets was $1.2 million, $1.2 million and $0.4 million for the years ended December 31, 2025, 2024 and 2023, respectively. The remaining weighted-average useful life of the Company’s amortizing intangible assets was 5.2 years as of December 31, 2025. No impairment charges were recorded during the years ended December 31, 2025, 2024 and 2023.
The following table presents the estimated amortization expense related to intangible assets as of December 31, 2025:
(in thousands)
Period:
2026$1,195 
20271,195 
20281,195 
20291,195 
20301,195 
Thereafter200 
Total$6,175 
v3.25.4
ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS
 12 Months Ended
Dec. 31, 2025
Asset Retirement Obligation And Environmental Remediation Obligations [Abstract]  
ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS
Asset Retirement Obligations
The Company estimates ARO based on the requirements to reclaim certain land areas associated with mineral extraction activities and certain related facilities at Mountain Pass. Minor reclamation activities related to discrete portions of the Company’s operations are ongoing. As of December 31, 2025, the Company estimated a significant portion of the cash outflows for major reclamation activities, including the retirement of Mountain Pass, will be incurred beginning in 2053.
In the fourth quarter of 2024, as a result of an update to the life of mine, the Company revised its estimated timing and cash flows pertaining to the settlement of the reclamation and removal activities associated with Mountain Pass, estimating that a significant portion of the cash outflows will now be incurred beginning in 2053 instead of 2056. The change in estimates resulted in an ARO increment of $1.3 million, which increased the carrying amounts of associated property, plant and equipment.
The following is a summary of the Company’s ARO:
December 31,
(in thousands)20252024
Beginning balance$7,395 $5,702 
Obligations settled(184)(184)
Accretion expense580 429 
Obligations incurred— 159 
Revision in estimated cash flows— 1,289 
Ending balance$7,791 $7,395 
The non-current portions of the Company’s asset retirement obligations, which are included in “Other non-current liabilities” within the Company’s Consolidated Balance Sheets, were $7.7 million and $7.2 million as of December 31, 2025, and 2024, respectively. The current portions, which are included in “Other current liabilities” within the Company’s Consolidated Balance Sheets, were not material. The total estimated future undiscounted cash flows required to satisfy the Company’s ARO as of December 31, 2025 and 2024, were $51.4 million and $51.6 million, respectively. As of December 31, 2025, the credit-adjusted risk-free rate ranged between 6.5% and 11.5% depending on the timing of expected settlement and when the increment was recognized. Other than those discussed above, there were no significant increments or decrements for the years ended December 31, 2025, 2024, and 2023.
Environmental Obligations
The Company has certain environmental monitoring and remediation obligations related to the groundwater contamination in and around Mountain Pass. The Company engages environmental consultants to develop remediation plans and the related
cost projections, which are used to develop an estimate of future cash payments needed to satisfy the Company’s environmental obligations. As assessments and remediation progress occur, the Company periodically reviews its estimates and records any necessary adjustments in the period in which new information becomes available.
As of December 31, 2025, the Company estimated the cash outflows related to these environmental activities will be incurred annually over the next 30 years but could be longer. The Company’s environmental obligations are measured at the expected value of future cash outflows discounted to their present value using a discount rate of 4.84%. There were no significant changes in the estimated remaining costs for the year ended December 31, 2025.
During the fourth quarter of 2024, as a result of updating its estimated cash flows required to satisfy its existing environmental monitoring and remediation obligations, the Company recorded an additional $2.0 million liability, with a corresponding loss recorded in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2024.
There were no significant changes in the estimated remaining costs for the year ended December 31, 2023.
The total estimated aggregate undiscounted cost of $40.3 million and $39.5 million as of December 31, 2025 and 2024, respectively, principally related to groundwater monitoring and remediation activities required by state and local agencies. Based on the Company’s estimate of the cost, timing and the assumption that payments are considered to be fixed and reliably determinable, the Company has discounted the liability. The non-current portions of the Company’s environmental obligations, which are included in “Other non-current liabilities” within the Company’s Consolidated Balance Sheets, were $18.4 million and $18.1 million as of December 31, 2025, and 2024, respectively. The current portions, which are included in “Other current liabilities” within the Company’s Consolidated Balance Sheets, were not material.
As of December 31, 2025, the total environmental costs were as follows (in thousands):
Year ending December 31,
2026$919 
2027942 
2028965 
2029989 
20301,014 
Thereafter35,504 
Total40,333 
Effect of discounting(21,019)
Total environmental obligations$19,314 
Financial Assurances
The Company is required to provide certain government agencies with financial assurances relating to closure and reclamation obligations. As of December 31, 2025 and 2024, the Company had financial assurance requirements of $46.2 million and $45.5 million, respectively, which were satisfied with surety bonds placed with applicable California state and regional agencies.
v3.25.4
DEBT OBLIGATIONS
 12 Months Ended
Dec. 31, 2025
Debt Disclosure [Abstract]  
DEBT OBLIGATIONS DEBT OBLIGATIONS
The Company’s current and non-current portions of long-term debt were as follows:
December 31, 2025December 31, 2024
(in thousands)
Principal Amount
Unamortized Debt Discount and Issuance Costs
Carrying Amount
Principal AmountUnamortized Debt Issuance CostsCarrying Amount
Convertible Notes due 2026$67,499 $(88)$67,411 $67,699 $(440)$67,259 
Convertible Notes due 2030
862,793 (17,492)845,301 862,793 (21,323)841,470 
Samarium Project Loan150,000 (63,971)86,029 — — — 
Total long-term debt
$1,080,292 $(81,551)998,741 $930,492 $(21,763)908,729 
Less: Current portion
(67,411)— 
Total long-term debt, net of current portion
$931,330 $908,729 
Revolving Credit Facility
In August 2025, the Company entered into a credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and various other lenders, providing a $275.0 million revolving credit facility (the “Revolving Credit Facility”), maturing on August 25, 2030, with a $200.0 million letter of credit facility sublimit (the “Credit Agreement”). As of December 31, 2025, the Company had no outstanding borrowings under the Revolving Credit Facility, $160.0 million of unused letter of credit capacity, and $235.0 million of remaining borrowing capacity under the Revolving Credit Facility.
Interest rates under the Revolving Credit Facility are variable based on the Secured Overnight Financing Rate (“SOFR”), or at the Company’s option, at a base reference rate equal to the highest of (i) the federal funds rate plus 0.50%, (ii) the rate of interest last quoted by The Wall Street Journal as the “prime rate” in the U.S., (iii) the one-month SOFR rate plus 1.00% or (iv) 1.00% (the “Base Rate”), plus, as applicable, a margin ranging from 1.75% to 2.50% per annum for SOFR-based loans and ranging from 0.75% to 1.50% per annum for Base Rate-based loans, in each case, depending on the Company’s total leverage ratio.
The Credit Agreement is subject to financial covenants that are tested at the end of each fiscal quarter. From the inception of the Credit Agreement until the earlier of the fiscal quarter in which Consolidated EBITDA (as calculated and defined in the Credit Agreement) of the Company equals or exceeds $400.0 million for the test period and the fiscal quarter ending June 30, 2027 (the “Covenant Trigger Event”), the Company must maintain unrestricted cash and cash equivalents of at least $500.0 million. Following the Covenant Trigger Event, the Company is required to maintain a total leverage ratio of less than 4.00:1.00, or 4.50:1.00 for the fiscal quarter of and the three consecutive fiscal quarters following any material acquisition, and a cash interest coverage ratio greater than 3.0:1.0.
The Credit Agreement is guaranteed by the Company and its subsidiaries, subject to certain customary exceptions. Failure to comply with any of the covenants associated with the Credit Agreement could result in a default under its terms. Such a default would permit lenders to accelerate the maturity of the debt and to foreclose upon any collateral securing such debt. The Company was in compliance with the applicable financial covenant contained in the Credit Agreement as of December 31, 2025.
Convertible Notes due 2026
In March 2021, the Company issued $690.0 million in aggregate principal amount of 0.25% unsecured convertible senior notes (the “2026 Notes”) at a price of par. Interest on the 2026 Notes is payable on April 1st and October 1st of each year, beginning on October 1, 2021.
In March 2024, contemporaneous with the pricing of the 2030 Notes (as defined below), the Company entered into privately negotiated transactions with certain holders of the 2026 Notes to repurchase $400.0 million in aggregate principal amount of the 2026 Notes, using $358.0 million of the net proceeds from the offering of the 2030 Notes. The price the Company paid to repurchase the 2026 Notes, 89.5% of par value, was the same for each lender and approximated the trading price of the 2026 Notes at the time of the repurchases. Subsequent to the issuance of the 2030 Notes, the Company repurchased an additional $80.0 million in aggregate principal amount of the 2026 Notes in open market transactions for $70.6 million. As a
result of these repurchases in the first quarter of 2024, the Company recorded a $46.3 million gain on early extinguishment of debt included within the Company’s Consolidated Statements of Operations for the year ended December 31, 2024.
The remaining 2026 Notes outstanding mature, unless earlier converted, redeemed or repurchased, on April 1, 2026, and become convertible at the option of the holder beginning on January 1, 2026, through the business day immediately preceding the maturity date. The initial conversion price of the remaining 2026 Notes is approximately $44.28 per share, or 22.5861 shares per $1,000 principal amount of notes, subject to adjustment upon the occurrence of certain events. As of December 31, 2025, the 2026 Notes are included in “Current portion of long-term debt” within the Company’s Consolidated Balance Sheets due to the 2026 Notes maturing within one year.
In March 2024, the Company provided a written notice to the trustee and the holders of the 2026 Notes that it has irrevocably elected to fix the settlement method for all conversions that may occur subsequent to the election date, to a combination of cash and shares of the Company’s common stock with the specified dollar amount per $1,000 principal amount of the 2026 Notes, of $1,000. As a result, for any conversions of 2026 Notes occurring after the election date, a converting holder will receive (i) up to $1,000 in cash per $1,000 principal amount of the 2026 Notes and (ii) shares of the Company’s common stock for any conversion consideration in excess of $1,000 per $1,000 principal amount of the 2026 Notes converted. Prior to the election being made, the Company could have elected to settle the 2026 Notes in cash, shares of the Company’s common stock or a combination thereof.
Prior to January 1, 2026, at their election, holders of the 2026 Notes may convert their outstanding notes under the following circumstances: (i) during any calendar quarter commencing with the third quarter of 2021 if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (ii) during the five business day period after any five consecutive trading day period (the “2026 Notes measurement period”) in which the trading price (as defined in the indenture governing the 2026 Notes) per $1,000 principal amount of 2026 Notes for each trading day of the 2026 Notes measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; (iii) if the Company calls any or all of the 2026 Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or (iv) upon the occurrence of specified corporate events set forth in the indenture governing the 2026 Notes.
Convertible Notes due 2030
In March 2024, the Company issued $747.5 million in aggregate principal amount of 3.00% unsecured convertible senior notes that mature, unless earlier converted, redeemed or repurchased, on March 1, 2030 (the “2030 Notes” and, together with the 2026 Notes, the “Convertible Notes”), at a price of par. Interest on the 2030 Notes is payable on March 1st and September 1st of each year, beginning on September 1, 2024.
The 2030 Notes are convertible into cash, shares of the Company’s common stock or a combination thereof, at the Company’s election, at an initial conversion price of approximately $21.74 per share, or 45.9939 shares per $1,000 principal amount of 2030 Notes, subject to adjustment upon the occurrence of certain events.
Prior to December 1, 2029, at their election, holders of the 2030 Notes may convert their outstanding notes under the following circumstances: (i) during any calendar quarter commencing with the third quarter of 2024 if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day (the “Stock Price Condition”); (ii) during the five business day period after any ten consecutive trading day period (the “2030 Notes measurement period”) in which the trading price (as defined in the indenture governing the 2030 Notes) per $1,000 principal amount of 2030 Notes for each trading day of the 2030 Notes measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; (iii) if the Company calls any or all of the 2030 Notes for redemption, the notes called for redemption may be converted at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or (iv) upon the occurrence of specified corporate events set forth in the indenture governing the 2030 Notes. On or after December 1, 2029, and prior to the close of business on the second scheduled trading day immediately preceding the maturity date of the 2030 Notes, holders may convert their outstanding notes at any time, regardless of the foregoing circumstances.
Commencing the fourth quarter of 2025, the 2030 Notes became convertible at the option of the holders, and will remain convertible through the first quarter of 2026, due to the Stock Price Condition being met. On a quarterly basis, the Company
will reassess the Stock Price Condition; thus, the 2030 Notes may continue or cease to be convertible in future quarters depending on the performance of the Company’s stock price. As of December 31, 2025, no conversions had occurred.
The Company has the option to redeem for cash the 2030 Notes, in whole or in part, beginning on March 5, 2027, if certain conditions are met as set forth in the indenture governing the 2030 Notes. The redemption price is equal to 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest.
Capped Call Options
In March 2024, in connection with the offering of the 2030 Notes, the Company entered into privately negotiated capped call transactions (the “Capped Call Options”) with certain financial institutions (“Counterparties”). The Capped Call Options cover, subject to anti-dilution adjustments substantially similar to those in the 2030 Notes, 34.4 million shares of the Company’s common stock, the same number of shares that initially underlie the 2030 Notes issued in March 2024. The Capped Call Options have an expiration date of March 1, 2030, subject to earlier exercise.
The Capped Call Options are intended, subject to the Company’s discretion and depending on whether it elects to exercise its rights under such options, to reduce the potential dilution to the Company’s common stock upon conversion of the 2030 Notes and/or offset cash payments the Company is required to make in excess of the principal amount of the converted 2030 Notes, as the case may be. This would apply in the event that the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Options, is greater than the strike price of the Capped Call Options, which initially corresponds to the initial conversion price of the 2030 Notes, or approximately $21.74 per share of common stock, with such reduction and/or offset subject to an initial cap of $31.06 per share of the Company’s common stock.
The Capped Call Options are separate transactions, entered into by the Company with each of the Counterparties, and are not part of the terms of the 2030 Notes. Holders of the 2030 Notes do not have any rights with respect to the Capped Call Options. The Capped Call Options meet the criteria for classification as equity and, as such, are not remeasured each reporting period. During the first quarter of 2024, the Company paid $65.3 million for the Capped Call Options, which was recorded as a reduction to “Additional paid-in capital” within the Company’s Consolidated Balance Sheets along with the offsetting associated deferred tax impact of $15.9 million.
The Company elected to integrate the Capped Call Options with those 2030 Notes issued in March 2024 for federal income tax purposes pursuant to applicable U.S. Treasury Regulations. Accordingly, the $65.3 million gross cost of the purchased Capped Call Options will be deductible for income tax purposes as original discount interest over the term of the 2030 Notes.
Convertible Notes Debt Exchange
In December 2024, the Company entered into privately negotiated exchange agreements with certain holders of its 2026 Notes (the “Debt Exchange Agreements”). Pursuant to the Debt Exchange Agreements, $142.3 million in aggregate principal amount of the 2026 Notes was exchanged for $115.3 million in aggregate principal amount of the 2030 Notes (the “Debt Exchange”), which had the same terms and conditions as the 2030 Notes issued in March 2024.
As a result of the Debt Exchange, the Company recorded a $6.6 million gain on early extinguishment of debt, included within the Company’s Consolidated Statements of Operations for the year ended December 31, 2024; a $13.8 million increase to additional paid-in capital (net of the associated deferred tax impact of $4.0 million), as the 2030 Notes pertaining to this Debt Exchange were issued at a substantial premium; and total debt issuance costs of $4.5 million. For the avoidance of doubt, the 2030 Notes issued as part of the Debt Exchange are not associated with the Capped Call Options.
Samarium Project Loan
As discussed in Note 3, “Public-Private Partnership with U.S. Department of War,” in August 2025, the Company issued a $150.0 million unsecured promissory note to the DoW with a 12-year term, maturing on August 1, 2037. The Samarium Project Loan bears interest at a rate of 5.38% per annum, calculated as the 10-year U.S. Treasury constant maturity rate plus 1.00%. Interest on the Samarium Project Loan is payable in cash quarterly in arrears on the 15th day of each calendar quarter, beginning on October 15, 2025.
The Samarium Project Loan was recorded at its allocated fair value, based on its relative fair value to the other Issued Instruments. This resulted in a debt discount of $64.0 million as the Samarium Project Loan bears interest at a rate lower than the market interest rate applicable to the Company at the time the promissory note was issued. See Note 3, “Public-Private Partnership with U.S. Department of War,” for additional information regarding the allocation of consideration and issuance
costs. The debt discount and issuance costs associated with the Samarium Project Loan are amortized to interest expense over the term of the note at an effective interest rate of 12.3%.
The Company may prepay the Samarium Project Loan, in whole or in part, at any time, including all accrued interest, without premium, cost or penalty. The outstanding principal and all accrued and unpaid interest under the Samarium Project Loan become immediately due and payable upon the occurrence of certain conditions, such as payment defaults, as specified in the promissory note to the DoW.
Equipment Notes
In December 2024, the Company and Caterpillar Financial Services Corporation entered into an uncommitted credit facility (the “Uncommitted Credit Facility”) with a principal amount of up to $25.0 million, which was subsequently increased to $40.0 million in December 2025. During the year ended December 31, 2025, the Company executed promissory notes under the Uncommitted Credit Facility to finance new equipment, including trucks and wheel loaders, for use at Mountain Pass. As of December 31, 2025, the Company had $15.7 million of remaining borrowing capacity under the Uncommitted Credit Facility. The Company’s equipment notes, which are secured by the purchased equipment, have terms of between 4 years and 6 years and fixed interest rates of between 6.7% and 7.4% per annum. The purchase of equipment through the execution of these notes is disclosed as a non-cash investing and financing activity in Note 23, “Supplemental Cash Flow Information.”
The current and non-current portions of the equipment notes, which are included within the Consolidated Balance Sheets in “Other current liabilities” and “Other non-current liabilities,” respectively, were as follows:
December 31,
(in thousands)20252024
Equipment notes
Current$3,904 $2,098 
Non-current20,366 539 
$24,270 $2,637 
Interest expense, net
Interest expense, net, including interest costs related to the Convertible Notes, was as follows:
For the year ended December 31,
(in thousands)202520242023
Interest cost on Convertible Notes:
Coupon interest$26,053 $19,256 $1,725 
Amortization of debt issuance costs4,182 3,901 3,536 
Total Convertible Notes interest cost
30,235 23,157 5,261 
Samarium Project Loan interest cost
4,376 — — 
Other interest cost
3,046 244 319 
Interest capitalized to property, plant and equipment, net
(6,176)(391)(326)
Interest expense, net
$31,481 $23,010 $5,254 
The debt issuance costs associated with the 2026 Notes and the 2030 Notes are being amortized to interest expense over the terms of each note at effective interest rates of 0.51% and 3.52%, respectively. The remaining terms of the 2026 Notes and the 2030 Notes were 0.3 years and 4.2 years, respectively, as of December 31, 2025.
As of both December 31, 2025 and 2024, accrued and unpaid interest pertaining to the Convertible Notes was $8.7 million, and is included in “Other current liabilities” within the Company’s Consolidated Balance Sheets.
Debt Maturities
The following is a schedule of debt repayments as of December 31, 2025:
(in thousands)2026 Notes2030 Notes
Samarium Project Loan
Equipment Notes
Year ending December 31,
2026$67,499 $— $— $3,904 
2027— — — 4,294 
2028— — — 4,606 
2029— — — 4,782 
2030— 862,793 — 5,096 
Thereafter— — 150,000 1,588 
Total minimum payments$67,499 $862,793 $150,000 $24,270 
As of December 31, 2025, other than the Credit Agreement, none of the agreements governing the Company’s indebtedness contain financial covenants.
v3.25.4
OPERATING LEASES
 12 Months Ended
Dec. 31, 2025
Leases [Abstract]  
OPERATING LEASES OPERATING LEASES
The Company’s operating leases consist primarily of corporate office space, warehouses, and equipment used in its operations; the Company’s finance leases are not material.
Lease terms on the Company’s operating leases range from approximately one month to eight years. The majority of these leases require fixed monthly lease payments that may be subject to annual increases throughout the lease term. The Company’s lease agreements do not contain material residual value guarantees or restrictive covenants. Certain leases include renewal options at the election of the Company to extend the lease for an additional one to five years. As of December 31, 2025, the Company was not reasonably certain of exercising any material purchase, renewal, or termination options contained within its lease agreements. No ROU asset impairment charges were recorded during the years ended December 31, 2025, 2024 and 2023.
The Company determined that the DoW Offtake Agreement contains an embedded lease of the 10X Facility as a result of the DoW’s (i) right to obtain substantially all of the economic benefits of the 10X Facility and (ii) ability to direct the use of the 10X Facility for magnet production. See Note 3, “Public-Private Partnership with U.S. Department of War,” for more information about the DoW Offtake Agreement.
Under the terms of the DoW Offtake Agreement, certain costs related to the development and commissioning of the 10X Facility incurred prior to the Commercial Operation Date are reimbursable by the DoW. Reimbursements will be initially deferred as a contract liability and subsequently recognized into revenue as the Company fulfills its obligations under the contract. As of December 31, 2025, the contract liability for these reimbursements, which is included within the Consolidated Balance Sheets in non-current “Deferred revenue,” totaled $2.3 million. Furthermore, certain of these development and commissioning costs of the 10X Facility qualify for capitalization as costs to fulfill a contract with a customer. As of December 31, 2025, the Company capitalized $2.3 million of these contract fulfillment costs, which are included within the Consolidated Balance Sheets in “Other non-current assets.” These costs will be expensed following the pattern of revenue recognized from the reimbursements under the contract.
Total operating lease cost included the following components:
Location on Consolidated Statements of Operations
For the year ended December 31,
(in thousands)202520242023
Operating lease cost
Primarily Selling, general and administrative
$3,039 $1,916 $1,328 
Short-term lease cost
Primarily Cost of sales (excluding depreciation, depletion and amortization) (including related party)
3,670 3,163 2,134 
$6,709 $5,079 $3,462 
Information related to our operating lease terms and discount rates was as follows:
December 31,
20252024
Weighted-average remaining lease term
3.6 years5.7 years
Weighted-average discount rate
6.5 %6.9 %
As of December 31, 2025, the maturities of the Company’s operating lease liabilities were as follows:
(in thousands)
Period:
2026$3,863 
20273,851 
20282,758 
20291,436 
20301,227 
Total lease payments13,135 
Less: Imputed interest(1,490)
Total$11,645 
Supplemental disclosure for the Consolidated Balance Sheets related to the Company’s operating leases is as follows:
Location on Consolidated Balance Sheets
December 31,
(in thousands)20252024
Operating leases:
Right-of-use assets
Other non-current assets
$13,214 $8,680 
Operating lease liability, currentOther current liabilities$3,216 $1,066 
Operating lease liability, non-current
Other non-current liabilities
8,429 5,798 
Total operating lease liabilities$11,645 $6,864 
v3.25.4
INCOME TAXES
 12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
INCOME TAXES INCOME TAXES
Income tax benefit (expense) consisted of the following:
For the year ended December 31,
(in thousands)202520242023
Current:
Federal$1,874 $148 $(178)
State(367)— (135)
Total current1,507 148 (313)
Deferred:
Federal30,178 21,883 (11,334)
State215 5,892 2,879 
Total deferred30,393 27,775 (8,455)
Total income tax benefit (expense)$31,900 $27,923 $(8,768)
Income (loss) before income taxes, by tax jurisdiction, was as follows:
For the year ended December 31,
(in thousands)202520242023
United States$(117,774)$(93,347)$33,075 
Income taxes differed from the amounts computed by applying the U.S. federal income tax rate of 21% to pretax income as a result of the following:
For the year ended December 31,
202520242023
(in thousands, except tax rates)PercentAmountPercentAmountPercentAmount
Computed income tax benefit (expense) at the statutory rate
21.0 %$24,733 21.0 %$19,603 21.0 %$(6,946)
Changes resulting from:
State and local income taxes, net of federal (national) income tax effect:
State and local income taxes, net of federal benefits(1)
2.8 %3,302 1.8 %1,700 2.6 %(867)
California Competes Tax Credit, net of federal detriment0.9 %1,019 1.9 %1,778 (11.3)%3,753 
State valuation allowance, net of federal benefits
(3.9)%(4,562)(0.1)%(50)4.1 %(1,360)
State rate change, net of federal benefits
0.2 %223 1.5 %1,354 (2.7)%872 
Tax credits:
Section 48C Qualifying Advanced Energy Project Tax Credit1.6 %1,911 0.2 %148 — %— 
Nontaxable or nondeductible items:
Limitation on officers’ compensation
(3.2)%(3,735)(1.9)%(1,815)11.0 %(3,640)
Percentage depletion in excess of basis
3.2 %3,761 3.5 %3,284 — %— 
Nondeductible transaction costs
(1.4)%(1,639)— %— — %— 
Section 45X Advanced Manufacturing Production Credit
3.6 %4,266 3.8 %3,543 (0.1)%38 
Other nontaxable or nondeductible items
(0.3)%(400)— %— — %— 
Other reconciling items:
Return-to-provision adjustments
1.7 %1,952 (0.2)%(202)0.5 %(155)
Excess tax benefits (expense) on stock-based compensation
0.8 %927 (1.4)%(1,312)0.6 %(190)
Other, net0.1 %142 (0.2)%(108)0.8 %(273)
Total effective tax rate and income tax benefit (expense)
27.1 %$31,900 29.9 %$27,923 26.5 %$(8,768)
(1)State taxes in California made up the majority (greater than 50%) of the tax effect in this category.
The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows:
December 31,
(in thousands)20252024
Deferred tax assets:
Asset retirement and environmental obligations$6,585 $6,442 
Net operating losses89,408 70,593 
Inventories4,436 1,828 
Stock-based compensation7,979 5,958 
Lease liabilities
2,991 1,852 
Credits15,491 11,119 
Capped call options8,095 9,846 
Deferred investment tax credit liability
6,139 5,805 
Deferred revenue
8,226 — 
Other2,710 3,052 
Gross deferred tax assets152,060 116,495 
Less: Valuation allowance(6,318)(1,756)
Net deferred tax assets145,742 114,739 
Deferred tax liabilities:
Property, plant and equipment(101,101)(103,133)
ROU assets
(3,366)(2,335)
Mineral rights(89,025)(92,533)
Other(3,808)(2,047)
Total deferred tax liabilities(197,300)(200,048)
Non-current deferred tax liabilities, net$(51,558)$(85,309)
California Competes Tax Credit
In October 2021, the Company was awarded a $14.8 million California Competes Tax Credit (“CCTC”) available to offset its California state income tax liability with varying amounts allocated to each year within a five-year period, which ended with the 2025 tax year. During each such year, the Company achieved all the specified milestones, which related to employees hired in California, the annual wage of these employees, and capital investments made by the Company within the state. Each year’s credit may be “clawed back” if the milestones are not continually met for a three-year period following the year of achievement. For the years ended December 31, 2025, 2024 and 2023, the Company recorded a credit of $1.3 million, $2.3 million, and $4.8 million, respectively. Of the total CCTC recorded, $5.8 million remains available for the Company to use in future tax years.
Section 48C Qualifying Advanced Energy Project Tax Credit
In March 2024, the Company was awarded a $58.5 million Section 48C Qualifying Advanced Energy Project Tax Credit (the “48C Credit”) to advance the construction of the Independence Facility (the “48C Project”). The 48C Credit is an investment tax credit equal to 30% of qualified investments for certified projects that meet prevailing wage and apprenticeship requirements. The 48C Credit is not eligible for direct pay (i.e., it is nonrefundable); however, it is transferable to an unrelated taxpayer at a negotiated rate. The 48C Project was certified by the Department of Energy on September 2, 2025, and all eligible assets must be placed into service within two years of this date. During the years ended December 31, 2025 and 2024, the Company placed into service eligible assets and recorded 48C Credits of $3.4 million and $27.8 million, respectively.
The Company initially deferred the 48C Credits and will recognize them as a reduction to income tax expense (or an increase to income tax benefit) on a straight-line basis over the remaining estimated useful life of associated long-lived assets. As of December 31, 2025, the Company’s current and non-current deferred investment tax credit liabilities were $2.4 million and $26.9 million, respectively. As of December 31, 2024, the Company’s current and non-current deferred investment tax
credit liabilities were $2.1 million and $25.5 million, respectively. The current and non-current amounts are included in “Other current liabilities,” and “Deferred investment tax credit,” respectively, within the Company’s Consolidated Balance Sheets.
Other Tax Matters
As of December 31, 2025 and 2024, the Company had net operating loss (“NOL”) carryforwards for federal income tax purposes of $390.7 million and $316.1 million, respectively, and $106.6 million and $60.4 million, respectively, for state income tax purposes. The federal NOL may be carried forward indefinitely. Of the total state NOL, $105.6 million will expire in 2044 and 2045, if unused, and $1.0 million may be carried forward indefinitely. As of December 31, 2025, the Company also had tax credit carryforwards of $17.2 million, of which $5.8 million and $9.2 million will begin to expire in 2029 and 2044, respectively, if unused, and $2.2 million may be carried forward indefinitely. As of December 31, 2025, the Company considered positive and negative evidence to determine the need for a valuation allowance to offset its deferred tax assets. During 2025, the Company recorded a full valuation allowance on CCTC and maintained its valuation allowance on California alternative minimum tax credits carried forward from prior years. All other deferred tax assets will be realized through future taxable temporary differences, principally resulting from the deferred tax liabilities on Property, plant and equipment and Mineral rights.
The Company evaluated its tax positions for the years ended December 31, 2025, 2024 and 2023, and determined there were no uncertain tax positions requiring recognition in the Consolidated Financial Statements. The tax years from 2022 onward remain open to examination by the taxing jurisdictions to which the Company is subject.
In August 2022, the U.S. government enacted the Inflation Reduction Act of 2022, which, among other things, provides several tax incentives to promote clean energy adoption for tax years beginning after December 31, 2022. Specifically, the Section 45X Advanced Manufacturing Production Credit (the “45X Credit”) provides a credit equal to 10% of eligible “production costs incurred” with respect to the production and sale of critical minerals, including NdPr oxide. For more information on the 45X Credit, see Note 17, “Government Grants.”
In July 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted into law. Among other provisions, the OBBBA includes significant provisions, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act. Additionally, the OBBBA established a phase-out for applicable critical minerals starting after December 31, 2030, with credits reduced to 75% in 2031, 50% in 2032, 25% in 2033, and eliminated after December 31, 2033. The enactment of the tax reform provisions did not have a material impact on our Consolidated Financial Statements.
v3.25.4
COMMITMENTS AND CONTINGENCIES
 12 Months Ended
Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]  
COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES
Litigation: The Company may become party to lawsuits, administrative proceedings, and government investigations, including environmental, regulatory, construction, and other matters, in the ordinary course of business. Large, and sometimes unspecified, damages or penalties may be sought in some matters, and certain matters may require years to resolve. Other than the matter described below, the Company is not aware of any pending or threatened litigation that it believes would have a material adverse effect on its Consolidated Financial Statements.
The Company is currently in a dispute with a general contractor for a construction project, which is in binding arbitration. While the Company disputes that it owes any monies (and believes it has a valid claim against the contractor) in connection with this construction project, at present, the Company has accrued an estimate of the potential loss, which is included in “Accrued construction costs” within “Accrued liabilities” in the Company’s Consolidated Balance Sheets. If an unfavorable outcome were to occur in the binding arbitration, it is possible that the impact could be material to the Company’s Consolidated Financial Statements in the period in which the contingency is resolved.
v3.25.4
REDEEMABLE PREFERRED STOCK
 12 Months Ended
Dec. 31, 2025
Temporary Equity Disclosure [Abstract]  
REDEEMABLE PREFERRED STOCK REDEEMABLE PREFERRED STOCK
On July 10, 2025, the Board of Directors for the Company authorized the designation of 400,000 shares of Series A Preferred Stock with a stated value of $1,000 per Series A Preferred Stock (the “Stated Value”) from the Company’s existing 50,000,000 authorized but unissued shares of preferred stock. The Company issued the authorized Series A Preferred Stock through a private placement to the DoW for cash consideration of $400.0 million.
The Series A Preferred Stock was initially recorded at its allocated fair value, based on its relative fair value to the other Issued Instruments, of $413.6 million, net of allocated issuance costs of $4.8 million (see Note 3, “Public-Private Partnership with U.S. Department of War,” for additional information regarding the allocation of consideration and issuance costs). As of December 31, 2025, the carrying amount of the Company’s Series A Preferred Stock, net of issuance costs, was $413.6 million. The Company did not adjust the carrying amount of the Series A Preferred Stock to the current redemption value as a deemed
liquidation event was not probable as of December 31, 2025. Subsequent adjustments to increase or decrease the carrying amount to the ultimate redemption value will be made only if a deemed liquidation event (i) has occurred or (ii) becomes probable of occurring in the future.
Dividends: Shares of the Series A Preferred Stock accrue cumulative dividends at a rate of 7.0% per year, compounding quarterly and payable solely in-kind through an increase to the Stated Value of each share of Series A Preferred Stock (each such dividend, a “PIK Dividend”). The Stated Value plus compounded PIK Dividends (the “Accumulated Stated Value”) is only payable by the Company in cash or other assets upon the occurrence of certain insolvency events, including a deemed liquidation event (i.e., it represents the liquidation preference of the holders of the Series A Preferred Stock). Further, the PIK Dividend does not influence the conversion price or the number of common shares that would be issued to the holders of the Series A Preferred Stock upon conversion. As the PIK Dividend is a liquidation preference, it will not be accounted for as an adjustment to the Series A Preferred Stock’s carrying amount until a deemed liquidation event occurs or becomes probable of occurring.
The holders of the Series A Preferred Stock also participate in any dividends declared and paid to holders of the Company’s common stock. Within 15 business days following the end of a calendar year, the Company will pay cash to the holder of each share of Series A Preferred Stock, on an as-converted basis, the amount, if any, by which the aggregate cash dividends paid by the Company on each share of common stock in the prior year exceed 7.0% of the Company’s common stock closing share price on the last trading day of the preceding year (the “Special Payment”).
Voting Rights: The Series A Preferred Stock is nonvoting on all matters, other than those that would have a material adverse effect on the special rights, powers, preferences or privileges of the Series A Preferred Stock.
Conversion: At the election of the DoW, the Series A Preferred Stock is convertible at any time into 13,320,013 shares of the Company’s common stock at an initial conversion price of $30.03, subject to customary anti-dilution adjustments.
At the election of the Company, any time after the five-year anniversary of issuance, if the closing price per share of the Company’s common stock exceeds 150% of the then-current conversion price for at least 20 trading days in any period of 30 consecutive trading days, the Company may elect to convert all or any portion of the then-outstanding shares of Series A Preferred Stock into common stock at the then-current conversion price.
Redemption: Redemption is contingent upon certain insolvency events, including a deemed liquidation event, or upon certain reorganization events (e.g., share exchange, recapitalization, consolidation, or merger). The Series A Preferred Stock is classified as redeemable preferred stock (i.e., temporary equity) within the Company’s Consolidated Balance Sheets due to redemption rights for a deemed liquidation event that, in certain circumstances, is not solely within the Company’s control.
Liquidation Rights: In the event of a voluntary or involuntary liquidation (e.g., a deemed liquidation event), holders of the Series A Preferred Stock will be entitled to a distribution before any distribution to the holders of the Company’s common stock. The liquidation preference payable in cash or other assets equals the greater of (i) the Accumulated Stated Value plus accrued and unpaid dividends (the “Liquidation Floor”) and (ii) the amount the holders of the Series A Preferred Stock would have received had all the Series A Preferred Stock been converted into common stock at the then-current conversion price immediately prior to such liquidation event. As of December 31, 2025 and 2024, the aggregate minimum liquidation preference (i.e., the Liquidation Floor) was $413.5 million and zero, respectively.
v3.25.4
SUPPLEMENTAL BALANCE SHEET INFORMATION
 12 Months Ended
Dec. 31, 2025
Balance Sheet Related Disclosures [Abstract]  
SUPPLEMENTAL BALANCE SHEET INFORMATION SUPPLEMENTAL BALANCE SHEET INFORMATION
The Company’s other receivables consisted of the following:
December 31,
(in thousands)20252024
PPA income receivable
$51,016 $— 
Government grant receivable
41,980 19,799 
Apple prepayment receivable
32,000 — 
DoW reimbursement receivable
2,328 — 
Other receivables
3,714 800 
Other receivables
$131,038 $20,599 
The Company’s accrued liabilities consisted of the following:
December 31,
(in thousands)20252024
Accrued payroll and related
$21,896 $17,370 
Accrued construction costs
60,289 36,016 
Accrued taxes
2,105 4,039 
Other accrued liabilities
10,796 7,302 
Accrued liabilities$95,086 $64,727 
v3.25.4
REVENUE RECOGNITION
 12 Months Ended
Dec. 31, 2025
Revenue from Contract with Customer [Abstract]  
REVENUE RECOGNITION REVENUE RECOGNITION
The following table disaggregates the Company’s revenue from contracts with customers by segment and by type of good sold, which are transferred to customers at a point in time:
For the year ended December 31,
(in thousands)
202520242023
Revenue category by segment
Materials segment
Rare earth concentrate
$41,992 $144,363 $252,468 
NdPr oxide and metal115,131 57,762 695 
Other revenue
3,246 1,730 282 
Total Materials segment revenue160,369 203,855 253,445 
Magnetics segment
Magnetic precursor products
66,861 — — 
Intersegment eliminations(1)
(2,789)— — 
Total revenue
$224,441 $203,855 $253,445 
(1)Represents the elimination of intersegment revenues associated with NdPr oxide sales made by the Materials segment to the Magnetics segment.
Rare earth concentrate revenue was primarily generated from sales to Shenghe under the applicable offtake agreements (see Note 21, “Related-Party Transactions” for additional information). The sales price of rare earth concentrate sold to Shenghe under the applicable agreements was based on a preliminary market price (net of taxes, tariffs, and certain other agreed charges) per MT and estimated exchange rate between the Chinese yuan and the U.S. dollar, with an adjustment for the ultimate market price of the product realized by Shenghe upon sales to their customers, including the impact of changes in the exchange rate between the Chinese yuan and the U.S. dollar.
NdPr oxide and metal revenue was generated from individual sales agreements as well as sales made under the Company’s distribution agreement with Sumitomo Corporation of Americas.
Magnetic precursor products revenue commenced in the first quarter of 2025 and was generated from sales of NdPr metal produced at the Independence Facility under the long-term supply agreement with GM. During the year ended December 31, 2025, the Company recognized $66.9 million of revenue under a bill-and-hold arrangement, under which control of the product transfers to the customer, but the product remains in the physical possession of the Company. The performance obligation is
satisfied at the point in time the finished product is packaged, segregated and ready for shipment to GM. There were no bill-and-hold transactions during the years ended December 31, 2024 and 2023.
Contract Balances: The following table summarizes the activity of the Company’s deferred revenue:
For the year ended December 31,
(in thousands)20252024
Beginning balance(1)
$100,000 $— 
Additions to deferred revenue125,051 100,000 
Revenue recognized during the period(2)
(66,861)— 
Ending balance(1)
$158,190 $100,000 
(1) Contract liabilities are included as current and non-current deferred revenue in the Company’s Consolidated Balance Sheets based on the Company’s expectation of when the performance obligations will be satisfied.
(2) All the revenue recognized during the year ended December 31, 2025, was included in the beginning deferred revenue balance.
Pursuant to the long-term agreement with GM, GM prepaid the Company $50.0 million in April 2025 and $100.0 million during the year ended December 31, 2024, for magnetic precursor products. The $50.0 million received in April 2025 was the final prepayment for magnetic precursor products.
As of December 31, 2025, the Company classified $74.3 million of the $83.1 million total remaining prepayment from GM as current deferred revenue and $8.8 million as non-current deferred revenue within its Consolidated Balance Sheets based on the Company’s expectation of when the performance obligations will be satisfied. The Company currently estimates that the performance obligations associated with the current deferred revenue from GM will be satisfied within one year after December 31, 2025, and between approximately one and two years after the same date for the non-current deferred revenue from GM. The Company’s estimate of when the performance obligations will be satisfied and revenue will be recognized is dependent upon various operational decisions that could impact the production levels of NdPr metal at the Independence Facility.
In July 2025, the Company entered into a definitive, long-term supply agreement with Apple for the development, manufacture, and supply of magnets from the Company’s Independence Facility, as well as the development and installation of scaled recycling capabilities at Mountain Pass to produce the contained rare earths from post-industrial and post-consumer recycled rare earth feedstocks. In connection with the agreement, and subject to achieving specified milestones, Apple agreed to make prepayments in the aggregate amount of $200.0 million for the purchase of magnets from the Company.
Pursuant to the supply agreement with Apple, Apple made an initial prepayment to the Company of $40.0 million in September 2025. In December 2025, the Company became entitled to an additional $32.0 million, resulting in a receivable recorded in “Other receivables” within the Company’s Consolidated Balance Sheets as of December 31, 2025. During the year ended December 31, 2025, the Company had not yet recognized any revenue under this arrangement. As of December 31, 2025, the Company classified the $72.0 million from Apple as non-current deferred revenue within its Consolidated Balance Sheets based on the Company’s expected satisfaction of the associated performance obligations beginning no earlier than 2027.
v3.25.4
GOVERNMENT GRANTS
 12 Months Ended
Dec. 31, 2025
Government Assistance [Abstract]  
GOVERNMENT GRANTS GOVERNMENT GRANTS
Asset-Based Grants: In February 2022, the Company was awarded a $35.0 million contract by the DoW Office of Industrial Base Analysis and Sustainment to design and build a facility to process HREE at Mountain Pass (the “HREE Facility”) (the “HREE Production Project Agreement”). The Company must utilize the funds to acquire property and equipment that will contribute to commercial-scale production of separated HREE at Mountain Pass. The Company will be paid fixed amounts upon the completion of certain project milestones. In exchange for these funds, the DoW will have certain rights to technical data following the completion of the project. The funds received pursuant to the HREE Production Project Agreement reduce the carrying amount of the fixed assets associated with the HREE Facility. During the years ended December 31, 2025 and 2023, the Company received $24.2 million and $2.8 million, respectively, from the DoW under the HREE Production Project Agreement, which reduced the carrying amount of assets under construction. No such funds were received from the DoW during the year ended December 31, 2024.
Income-Based Grants: As mentioned in Note 12, “Income Taxes,” in August 2022, the U.S. government enacted the Inflation Reduction Act of 2022, which, among other things, promotes clean energy adoption by providing several tax incentives for the domestic production and sale of eligible components for tax years beginning after December 31, 2022. Specifically, the 45X Credit provides a credit equal to 10% of eligible “production costs incurred” with respect to the
production and sale of critical minerals, including NdPr oxide. In October 2024, the Internal Revenue Service released final regulations on the 45X Credit which, among other things, added direct and indirect materials costs, including costs related to the extraction or acquisition of raw materials, to the definition of “production costs incurred,” which were previously excluded from the definition under the proposed regulations released in December 2023. The impact of the new guidance, including a cumulative adjustment to reflect the inclusion of direct and indirect costs on previous sales, was accounted for in the fourth quarter of 2024.
For corporate taxpayers, the 45X Credit is eligible for the direct pay election, which allows a refund of the credit in excess of tax liability. The Company made this election on its 2023 tax return, and such election is binding, unless revoked, for five years (i.e., through 2027). Accordingly, the Company determined that the 45X Credit is not within the scope of ASC 740, and instead, should be accounted for as an income-based grant. As such, during the period that the 45X Credit is refundable, the Company will recognize such credit as a reduction to various operating expenses, as presented in the table below, depending on the location of the corresponding expense, in the period the critical mineral is sold to a customer.
The current portion of the government grant receivable balance, which is included in “Other receivables” within the Company’s Consolidated Balance Sheets, was $42.0 million and $19.8 million as of December 31, 2025 and 2024, respectively. These balances reflect the cost of sales for tax purposes of critical minerals, specifically NdPr oxide and metal (of which NdPr oxide is a constituent element), including tax depreciation on such assets, reflective of bonus tax treatment, as applicable. Additionally, the receivable balance as of December 31, 2025, includes $19.8 million of 45X Credit claimed on the Company’s 2024 federal tax return, which has not yet been received. The Company received $19.4 million, related to the 45X Credit claimed on its 2023 federal tax return, during the year ended December 31, 2024.
The deferred government grant balance as of December 31, 2025 and 2024, related primarily to the inclusion of tax depreciation on assets that support production of critical minerals, reflective of bonus tax treatment, as applicable. The deferred government grant is recognized as a reduction of depreciation expense on a straight-line basis over the remaining estimated useful life of the underlying long-lived assets. The current portion of deferred government grant, which is included in “Other current liabilities” within the Company’s Consolidated Balance Sheets, was $2.4 million and $2.0 million as of December 31, 2025 and 2024, respectively.
The benefits (reduction of expenses) recognized in the Company’s Consolidated Statements of Operations pertaining to the 45X Credit were recorded as follows:
For the year ended December 31,
(in thousands)202520242023
Cost of sales (excluding depreciation, depletion and amortization) (including related party)$15,046 $12,199 $42 
Selling, general and administrative$2,858 $2,757 $— 
Depreciation, depletion and amortization$2,408 $1,916 $141 
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION
 12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION STOCKHOLDERS’ EQUITY AND STOCK-BASED COMPENSATION
Common Stock and Preferred Stock
The Company’s certificate of incorporation authorizes it to issue up to 500,000,000 shares, consisting of (i) 450,000,000 shares of common stock and (ii) 50,000,000 shares of preferred stock, each with a par value of $0.0001 per share. As discussed in Note 14, “Redeemable Preferred Stock,” on July 10, 2025, the Board of Directors for the Company authorized the designation of 400,000 shares of Series A Preferred Stock each with a stated value of $1,000 from the Company’s existing 50,000,000 authorized but unissued shares of preferred stock.
Public Offering of Common Stock
In July 2025, the Company completed an underwritten public offering of 13,590,908 shares of the Company’s common stock, par value $0.0001 per share, at a price to the public of $55.00 per share (the “Offering”). The underwriters purchased the shares of common stock at the price of $53.35, including the full exercise of the underwriters’ option to purchase additional shares of the Company’s common stock, solely to cover over-allotments. The Company’s net proceeds from the Offering were $724.2 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company.
Warrant
As discussed in Note 3, “Public-Private Partnership with U.S. Department of War,” on July 10, 2025, the Company issued the Warrant to the DoW, exercisable at any time, in whole or in part, in cash or in net share settlement at the DoW’s option, for a period of ten years prior to its expiration on July 10, 2035, for up to 11,201,659 shares of the Company’s common stock, at an initial exercise price of $30.03 per share. The strike price of $30.03 is subject to customary anti-dilution adjustments. The Warrant was classified as an equity instrument included in “Additional paid-in capital” within the Company’s Consolidated Balance Sheets and was initially recorded at its allocated fair value, based on its relative fair value to the other Issued Instruments, of $261.2 million, net of allocated issuance costs of $3.0 million (see Note 3, “Public-Private Partnership with U.S. Department of War,” for additional information regarding the allocation of consideration and issuance costs). As of December 31, 2025, no shares of common stock had been issued pursuant to the exercise of the Warrant.
Treasury Stock
In March 2024, the Company’s Board of Directors approved a share repurchase program (the “Program”) effective for one year under which the Company became authorized to repurchase up to an aggregate amount of $300.0 million of the Company’s outstanding common stock. In August 2024, the Company’s Board of Directors approved a $300.0 million increase to the Program, bringing the total authorized amount to $600.0 million. The authorization did not require the purchase of any minimum number of shares. On July 11, 2025, pursuant to the terms of the DoW Transaction Agreements, the Company terminated the Program.
During the year ended December 31, 2024, the Company repurchased 15.2 million shares of its common stock at an aggregate cost of $225.1 million. Of the number of shares repurchased, 12.3 million were repurchased in March 2024 contemporaneously with the 2030 Notes offering using $191.6 million of the net proceeds from such offering. The shares repurchased in connection with the 2030 Notes offering were privately negotiated transactions with or through one of the initial purchasers of the 2030 Notes or its affiliate at a price of $15.53 per share, which was equal to the closing price per share of common stock on the date of such transactions. No shares were repurchased during the year ended December 31, 2025.
Capped Call Options
In March 2024, in connection with the offering of the 2030 Notes, the Company entered into the Capped Call Options with the Counterparties, which cover, subject to anti-dilution adjustments substantially similar to those in the 2030 Notes, 34.4 million shares of the Company’s common stock, the same number of shares that initially underlie the 2030 Notes. The Capped Call Options meet the criteria for classification as equity and, as such, are not remeasured each reporting period. During the first quarter of 2024, the Company paid $65.3 million for the Capped Call Options, which was recorded as a reduction to “Additional paid-in capital” within the Company’s Consolidated Balance Sheets along with the offsetting associated deferred tax impact of $15.9 million. See Note 10, “Debt Obligations,” for additional information.
Stock-Based Compensation
2020 Incentive Plan: In November 2020, the Company’s stockholders approved the MP Materials Corp. 2020 Stock Incentive Plan (the “2020 Incentive Plan”), which permits the Company to issue stock options (incentive and/or non-qualified); stock appreciation rights (“SARs”); restricted stock, restricted stock units (“RSUs”) and other stock awards (collectively, the “Stock Awards”); and performance awards, which vest contingent upon the attainment of either or a combination of market- or performance-based goals. As of December 31, 2025, the Company has not issued any stock options or SARs.
Pursuant to the 2020 Incentive Plan, 9,653,671 shares of common stock were initially available for issuance. The number of shares of common stock available under the 2020 Incentive Plan may be increased annually on the first day of each calendar year, beginning with the year ended December 31, 2021, and continuing until (and including) the year ending December 31, 2030, with such annual increase equal to the lesser of (i) 2% of the number of shares of stock issued and outstanding on December 31st of the immediately preceding fiscal year and (ii) an amount determined by the Board of Directors. The number of shares of common stock that remain available for future grants under the 2020 Incentive Plan shall be reduced by the sum of the aggregate number of shares of common stock that become subject to outstanding options, outstanding free-standing SARs, outstanding Stock Awards, and outstanding performance awards denominated in shares of common stock, other than substitute awards. As of December 31, 2025, there were 4,150,457 shares available for future grants under the 2020 Incentive Plan.
In November 2025, the Board of Directors approved and authorized annual increases to the shares of common stock available for issuance under the 2020 Incentive Plan equal to 2% of the Company’s outstanding common stock as of December 31st of the immediately preceding year, with the first increase effective January 1, 2026, and continuing annually through the year ending December 31, 2030.
Market-Based PSUs: In February 2023, pursuant to the 2020 Incentive Plan, the Compensation Committee of the Company’s Board of Directors adopted a performance share plan (the “2023 Performance Share Plan”), pursuant to which, for the year ended December 31, 2023, the Company granted 62,709 of market-based performance stock units (“market-based PSUs”) at target. Additionally, in January 2024, pursuant to the 2020 Incentive Plan, the Compensation Committee of the Company’s Board of Directors adopted another performance share plan (the “2024 Performance Share Plan”), pursuant to which, for the year ended December 31, 2024, the Company granted 177,766 of market-based PSUs.
All market-based PSUs granted cliff vest after a requisite performance and service period of three years. The market-based PSUs have the potential to be earned at between 0% and 200% of the number of awards granted depending on the level of growth of the Company’s total shareholder return (“TSR”) as compared to the TSR of the S&P 400 Index and the S&P 400 Materials Group over the performance period. The fair value of the market-based PSUs was determined using a Monte Carlo simulation technique.
In January 2026, upon approval by the Compensation Committee of the Company’s Board of Directors, the market-based PSUs granted pursuant to the 2023 Performance Share Plan cliff vested after their requisite performance period and were earned at 200% of the number of awards granted based on the achieved TSR.
Performance-Based PSUs: In March 2025, pursuant to the 2020 Incentive Plan, the Compensation Committee of the Company’s Board of Directors adopted a performance share plan (the “2025 Performance Share Plan”). Pursuant to the 2025 Performance Share Plan, during the year ended December 31, 2025, the Company granted 235,533 of performance-based PSUs at target, all of which cliff vest after a requisite performance period of three years. The performance-based PSUs have a requisite service period of approximately three years and have the potential to be earned in 50% increments between 0% and 200% of the number of granted awards depending on the achievement of the performance conditions. The fair value of these performance-based PSUs was determined using the Company’s stock price on the grant date.
In October 2025, pursuant to the 2020 Incentive Plan, the Compensation Committee of the Company’s Board of Directors approved an additional grant of performance-based PSUs, pursuant to which, during the year ended December 31, 2025, the Company granted 400,382 of performance-based PSUs at target, all of which cliff vest after a requisite performance period of three, four, or five years. The performance-based PSUs have a requisite service period of approximately three, four, or five years and have the potential to be earned between 0% and 100% of the number of granted awards depending on the achievement of the performance conditions. The fair value of these performance-based PSUs was determined using the Company’s stock price on the grant date.
The weighted-average grant date fair value of the Company’s performance awards granted during the years ended December 31, 2025, 2024 and 2023 was $62.20, $26.09 and $50.40, respectively.
The following table contains information on the Company’s performance awards:
Number of SharesWeighted-Average Grant Date Fair Value
Nonvested as of January 1, 2025240,475 $32.43 
Granted757,748 $62.20 
Vested(3,189)$27.23 
Forfeited— $— 
Nonvested as of December 31, 2025995,034 $55.11 
As of December 31, 2025, the unamortized compensation cost not yet recognized related to performance awards totaled $48.1 million and the weighted-average period over which the costs are expected to be recognized was 3.3 years.
Stock Awards: The Company granted 1,118,518, 737,835 and 805,322 RSUs to employees during the years ended December 31, 2025, 2024, and 2023, respectively, which, with the exception of 189,670, 130,956 and 67,700 RSUs granted during the years ended December 31, 2025, 2024 and 2023, respectively, that vested immediately, vest ratably in equal installments over the requisite service period of 4 years.
Additionally, the Company granted 35,884, 71,148 and 48,177 RSUs to non-employee directors during the years ended December 31, 2025, 2024, and 2023, respectively, of which, 6,142, 15,252 and 10,691 vested immediately into tax-deferred stock units (“DSUs”) during the years ended December 31, 2025, 2024 and 2023, respectively. The remaining RSUs granted vest into DSUs upon the earlier of one year after the grant date and the next annual stockholder meeting. The DSUs are settled
as shares of common stock of the Company upon the earlier of (i) June 15th of the fifth year after grant, (ii) a change in control of the Company, or (iii) the director’s separation from the Company’s Board of Directors, unless the director elects to defer settlement until retirement.
The grant date fair value of the Company’s Stock Awards is based on the closing stock price of the Company’s shares of common stock on the date of grant. The weighted-average grant date fair value of Stock Awards granted during the years ended December 31, 2025, 2024 and 2023 was $30.19, $16.27 and $24.13, respectively.
The following table contains information on the Company’s Stock Awards:
Number of SharesWeighted-Average Grant Date Fair Value
Nonvested as of January 1, 20251,518,929 $24.71 
Granted1,154,402 $30.19 
Vested(847,618)$28.63 
Forfeited(121,590)$21.61 
Nonvested as of December 31, 20251,704,123 $26.69 
As of December 31, 2025, the unamortized compensation cost not yet recognized related to Stock Awards totaled $23.3 million and the weighted-average period over which the costs are expected to be recognized was 2.0 years. The total fair value of Stock Awards that vested during the years ended December 31, 2025, 2024 and 2023, was $29.3 million, $23.6 million and $20.7 million, respectively.
The Company’s stock-based compensation and related income tax benefit were recorded as follows:
For the year ended December 31,
(in thousands)202520242023
Cost of sales (excluding depreciation, depletion and amortization)(including related party)
$6,914 $3,311 $3,932 
Selling, general and administrative22,197 19,074 20,508 
Start-up costs
871 381 723 
Advanced projects and development181 417 73 
Total stock-based compensation expense$30,163 $23,183 $25,236 
Stock-based compensation capitalized to property, plant and equipment, net$4,628 $1,573 $1,868 
Income tax benefit for stock-based compensation arrangements
$6,595 $4,454 $— 
v3.25.4
FAIR VALUE MEASUREMENTS
 12 Months Ended
Dec. 31, 2025
Fair Value Disclosures [Abstract]  
FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS
ASC Topic 820, “Fair Value Measurement,” establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below:
Level 1:Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
Level 2:
Quoted prices in markets that are not active, quoted prices for similar assets or liabilities in active markets, quoted prices or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability and model-based valuation techniques (e.g., the Black-Scholes model) for which all significant inputs are observable in active markets;
Level 3:Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (supported by little or no market activity).
The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of assets and liabilities and their placement within the fair value hierarchy. The following methods and assumptions are used to estimate the fair value of each class of financial instruments for which it is practicable to estimate. The fair value of the Company’s accounts receivable, accounts payable, and accrued liabilities approximates their respective carrying amounts because of the immediate or short-term maturity of these financial instruments.
Cash, Cash Equivalents and Restricted Cash
The fair value of the Company’s cash, cash equivalents and restricted cash is classified within Level 1 of the fair value hierarchy. The carrying amounts reported in the Consolidated Balance Sheets approximate the fair value of cash, cash equivalents and restricted cash due to the short-term nature of these assets.
Short-term Investments
The fair value of the Company’s short-term investments, which are classified as available-for-sale securities, is estimated based on quoted prices in active markets and is classified as a Level 1 measurement.
Derivative Instrument
The Company’s derivative instrument pertains to the redemption feature included in the portion of the 2030 Notes that were issued in December 2024. This instrument’s fair value is measured using a binomial lattice model, which utilizes observable inputs (e.g., the Company’s stock price) and unobservable inputs (e.g., the expected volatility and instrument specific discount rate) that cause the valuation measurements to be classified as Level 3. The significant unobservable inputs used in the determination of the fair value of instruments classified as Level 3 have an inherent measurement uncertainty that, if changed, could result in higher or lower fair value measurements of the derivative instrument as of the reporting date. The following assumptions were used within the model:
Valuation Assumptions:
December 31, 2025
Expected volatility
79.6 %
Risk-free interest rate
3.7 %
Discount rate
7.7 %
Dividend yield
— %
Term to maturity
4.2 years
Stock price
$50.52
Convertible Notes
The fair value of the Company’s Convertible Notes is estimated based on quoted prices in active markets and is classified as a Level 1 measurement.
Samarium Project Loan
The fair value of the Company’s Samarium Project Loan is based on inputs that are directly observable for substantially the full term of the liability and is classified as a Level 2 measurement. Model-based valuation techniques for which all significant inputs are observable in active markets were used to calculate the fair value of this liability.
Equipment Notes
The fair value of the Company’s equipment notes is based on inputs that are directly observable for substantially the full term of the liability and is classified as a Level 2 measurement. Model-based valuation techniques for which all significant inputs are observable in active markets were used to calculate the fair values for these liabilities.
The Company’s financial instrument assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The carrying amounts and estimated fair values by input level of the Company’s financial instruments were as follows:
December 31, 2025
(in thousands)
Carrying
Amount
Fair ValueLevel 1Level 2Level 3
Financial assets:
Cash and cash equivalents$1,166,011 $1,166,011 $1,166,011 $— $— 
Short-term investments$664,275 $664,275 $664,275 $— $— 
Restricted cash$1,348 $1,348 $1,348 $— $— 
Derivative instrument
$8,708 $8,708 $— $— $8,708 
Financial liabilities:
2026 Notes$67,411 $82,449 $82,449 $— $— 
2030 Notes$845,301 $2,172,782 $2,172,782 $— $— 
Samarium Project Loan
$86,029 $98,081 $— $98,081 $— 
Equipment notes$24,270 $25,339 $— $25,339 $— 
December 31, 2024
(in thousands)
Carrying
Amount
Fair ValueLevel 1Level 2Level 3
Financial assets:
Cash and cash equivalents$282,442 $282,442 $282,442 $— $— 
Short-term investments$568,426 $568,426 $568,426 $— $— 
Restricted cash$1,161 $1,161 $1,161 $— $— 
Financial liabilities:
2026 Notes$67,259 $63,528 $63,528 $— $— 
2030 Notes$841,470 $902,395 $902,395 $— $— 
Equipment notes$2,637 $2,596 $— $2,596 $— 
The following table summarizes the changes in fair value of the Company’s Level 3 assets measured on a recurring basis:
(in thousands)
Derivative Instrument
Balance as of January 1, 2025$— 
Included in earnings(1)
8,708 
Balance as of December 31, 2025
$8,708 
(1)The gain is included in “Other income, net” within the Company’s Consolidated Statements of Operations.
v3.25.4
EARNINGS PER SHARE
 12 Months Ended
Dec. 31, 2025
Earnings Per Share [Abstract]  
EARNINGS PER SHARE EARNINGS (LOSS) PER SHARE
The following table reconciles the weighted-average common shares outstanding used in the calculation of basic earnings or loss per common share to the weighted-average common shares outstanding used in the calculation of diluted earnings or loss per common share:
For the year ended December 31,
202520242023
Weighted-average shares outstanding, basic170,126,753 166,840,611 177,181,661 
Assumed conversion of 2026 Notes
— 3,042,029 — 
Assumed conversion of restricted stock— — 609,326 
Assumed conversion of RSUs— — 361,225 
Weighted-average shares outstanding, diluted170,126,753 169,882,640 178,152,212 
The following table presents unweighted potentially dilutive shares that were not included in the computation of diluted earnings or loss per common share because to do so would have been antidilutive:
For the year ended December 31,
202520242023
2026 Notes
— — 15,584,409 
2030 Notes
39,683,215 39,683,215 — 
Series A Preferred Stock
13,320,013 — — 
Warrant
11,201,659 — — 
RSUs1,704,123 1,518,929 3,184 
PSUs552,589 — — 
Total66,461,599 41,202,144 15,587,593 
The following table presents the calculation of basic and diluted earnings or loss per common share:
For the year ended December 31,
(in thousands, except share and per share data)202520242023
Calculation of basic earnings (loss) per common share:
Net income (loss) attributable to common stockholders
$(85,874)$(65,424)$24,307 
Weighted-average shares outstanding, basic170,126,753 166,840,611 177,181,661 
Basic earnings (loss) per common share$(0.50)$(0.39)$0.14 
Calculation of diluted earnings (loss) per common share:
Net income (loss) attributable to common stockholders
$(85,874)$(65,424)$24,307 
Interest expense, net of tax(1):
2026 Notes
— 743 — 
Gain on early extinguishment of debt(1)(2)
— (32,426)— 
Diluted income (loss) attributable to common stockholders$(85,874)$(97,107)$24,307 
Weighted-average shares outstanding, diluted170,126,753 169,882,640 178,152,212 
Diluted earnings (loss) per common share$(0.50)$(0.57)$0.14 
(1)The year ended December 31, 2024, was tax-effected at a rate of 29.9%.
(2)Pertains to the 2026 Notes, a portion of which were repurchased during the year ended December 31, 2024.
In connection with the issuance of the 2030 Notes in March 2024, the Company entered into the Capped Call Options, which were not included for purposes of calculating the number of diluted shares outstanding, as their effect would have been anti-dilutive. The Company has not exercised any of the Capped Call Options as of December 31, 2025.
As discussed in Note 10, “Debt Obligations,” in March 2024, the Company provided a written notice to the trustee and the holders of the 2026 Notes that it has irrevocably elected to fix the settlement method for all conversions that may occur subsequent to the election date, to a combination of cash and shares of the Company’s common stock with the specified dollar amount per $1,000 principal amount of the 2026 Notes of $1,000. As a result, subsequent to the election, only the amounts in excess of the principal amount are considered in diluted earnings or loss per common share. The amount of the 2026 Notes settled in shares of common stock will have a dilutive impact on diluted earnings or loss per common share when the average market price of the Company’s common stock for a given period exceeds the conversion price, which was initially approximately $44.28 per share of common stock.
v3.25.4
RELATED PARTY TRANSACTIONS
 12 Months Ended
Dec. 31, 2025
Related Party Transactions [Abstract]  
RELATED PARTY TRANSACTIONS RELATED-PARTY TRANSACTIONS
Offtake Agreements: In 2024, the Company entered into an offtake agreement with Shenghe Resources (Singapore) International Trading Pte. Ltd. (“Shenghe”), a majority-owned subsidiary of Leshan Shenghe Rare Earth Co., Ltd. whose ultimate parent is Shenghe Resources Holding Co., Ltd., a leading global rare earth company listed on the Shanghai Stock Exchange (the “Shenghe Offtake Agreement”), that replaced and extended the then-existing offtake agreement with Shenghe.
Pursuant to the Shenghe Offtake Agreement, and subject to certain exclusions, Shenghe was obligated to purchase on a “take or pay” basis the rare earth concentrate produced by the Company as the exclusive distributor in China, with certain exceptions for the Company’s direct sales globally. In addition, at the discretion of the Company, Shenghe was required to purchase on a “take or pay” basis certain non-concentrate rare earth products, although the Company may have sold all non-concentrate rare earth products in its sole discretion to customers or end users in any jurisdiction. For a discussion on sales price, see Note 16, “Revenue Recognition.”
The initial term of the Shenghe Offtake Agreement was two years, with the option for the Company to extend the term for an additional one-year period. In July 2025, to align with the terms of the DoW Transaction Agreements and in further support of its domestic supply chain objectives, the Company ceased all sales of its products to China and did not extend the term of the Shenghe Offtake Agreement when it expired in January 2026.
Starting in the fourth quarter of 2025, Shenghe was no longer considered a related party of the Company.
Revenue and Cost of Sales: The Company’s related-party revenue and cost of sales were as follows:
For the year ended December 31,
(in thousands)202520242023
Revenue:
Rare earth concentrate$41,992 $143,586 $242,516 
NdPr oxide and metal$9,315 $14,452 $— 
Cost of sales (excluding depreciation, depletion and amortization)
$31,461 $109,549 $89,260 
Purchases of Materials and Supplies: The Company purchases certain reagent products (generally produced by an unrelated third-party manufacturer) used in the flotation process, as well as other materials from Shenghe in the ordinary course of business. For the years ended December 31, 2025, 2024 and 2023, during the period when Shenghe was considered a related party, these purchases totaled $19.7 million, $4.8 million and $8.3 million, respectively.
Accounts Receivable: As of December 31, 2025, there were no accounts receivable from related parties. As of December 31, 2024, $14.9 million of the trade accounts receivable as stated within the Company’s Consolidated Balance Sheets were receivable from and pertained to sales made to Shenghe in the ordinary course of business.
Aircraft Lease and Time Sharing Agreement: On November 13, 2024, the Company entered into an aircraft operating lease agreement effective as of January 1, 2025, with an entity affiliated with James H. Litinsky, the Company’s Chairman and Chief Executive Officer, providing for the lease of an aircraft (the “Aircraft Lease”). The rent payable by the Company under the Aircraft Lease is $0.5 million per year.
In addition, on November 13, 2024, the Company entered into a time sharing agreement effective as of January 1, 2025, with Mr. Litinsky, pursuant to which he may lease the aircraft from the Company for limited personal use (“Time Sharing Agreement”). For flights taken under the Time Sharing Agreement, Mr. Litinsky will pay for the actual expenses of such flights as listed in the Time Sharing Agreement, but not to exceed the maximum amount permitted under the Federal Aviation Administration rules.
v3.25.4
SEGMENT REPORTING
 12 Months Ended
Dec. 31, 2025
Segment Reporting [Abstract]  
SEGMENT REPORTING SEGMENT REPORTING
Pursuant to ASC 280, operating segments are defined as components of an enterprise engaged in business activities from which it may recognize revenues and incur expenses, about which discrete financial information is available and evaluated regularly by the CODM, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company’s Chief Executive Officer and Chief Operating Officer, collectively, have been identified as the Company’s CODM.
The Company’s reportable segments, which are primarily based on the Company’s internal organizational structure and types of products, are its two operating segments—Materials and Magnetics (no operating segments have been aggregated).
The Materials segment operates Mountain Pass, which produces rare earth products. The Materials segment currently generates revenue primarily from sales of NdPr oxide and metal, principally sold to customers in Japan, South Korea, and broader Asia. The Materials segment historically also generated revenue from sales of rare earth concentrate, which was primarily sold for further distribution to a single customer in China.
The Magnetics segment operates the Independence Facility, where the Company produces and sells magnetic precursor products and, beginning in December 2025, commenced manufacturing of NdFeB permanent magnets. The first sales of magnetic precursor products, including NdPr metal, were made to GM and began in the first quarter of 2025.
As part of the DoW Transaction Agreements, the Company has undertaken strategic initiatives and commitments that impact its segment operations. For the Materials segment, the PPA will provide a $110 per kg price floor for NdPr Products for ten years, mitigating the risks of commodity price fluctuations associated with NdPr; the DoW Transaction Agreements also support the Company’s efforts to accelerate and extend its HREE refining capability at Mountain Pass. For the Magnetics segment, the Company committed to expand capacity at the Independence Facility and to construct the 10X Facility, while the DoW committed to purchase the entire quantity of magnets produced by the Company at the 10X Facility under the DoW Offtake Agreement. See Note 3, “Public-Private Partnership with U.S. Department of War,” for additional details.
The CODM uses Segment Adjusted EBITDA as management’s primary segment measure of profit or loss in assessing segment performance and deciding how to allocate the Company’s resources. This measure enables the CODM to evaluate operational efficiency and segment performance by comparing current results to historical data, while also monitoring variances between actual results and forecasts to inform decisions on capital, personnel and other resource allocations across segments. Segment Adjusted EBITDA is calculated as segment revenues and price protection agreement income less significant segment expenses, specifically, cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense) and selling, general and administrative expenses (excluding stock-based compensation expense), as well as certain other operating expenses (referred to as “other segment items”). Significant segment expenses and other segment items also exclude certain costs that are non-recurring, non-cash or are not related to the segments’ underlying business performance. A reconciliation of total Segment Adjusted EBITDA to consolidated income or loss before income taxes for the years ended December 31, 2025, 2024 and 2023, is included in the tables below.
Certain costs are incurred at the corporate level and are partially allocated to the Company’s segments. These costs generally include shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. Each allocation is measured differently based on the specific facts and circumstances of the costs being allocated and is based on a combination of metrics deemed to best represent the expected benefit received by the operating segment. The remaining unallocated corporate costs, as well as costs related to executive compensation, investor relations and other corporate costs, are reported within Corporate expenses and other as a reconciling item to our consolidated results. Our allocation methodology is periodically evaluated and may change. The accounting policies for our operating segments are the same as those described in Note 2, “Significant Accounting Policies.”
As the Company’s CODM manages the Company’s assets on a consolidated basis, the CODM is not regularly provided asset information for the reportable segments. The Company does not have any material long-lived assets located outside of the U.S. For all of the periods presented below, the Company’s revenues were derived from U.S.-domiciled operations.
The following tables present the Company’s reportable segment information:
For the year ended December 31, 2025
(in thousands)MaterialsMagneticsTotal
Revenue from external customers
$157,580 $66,861 $224,441 
Intersegment revenues(1)
2,789 — 2,789 
160,369 66,861 227,230 
Elimination of intersegment revenues(1)
(2,789)
Total consolidated revenues$224,441 
Price protection agreement income
51,016 — 
Significant segment expenses:
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(2)
159,466 28,904 
Selling, general and administrative (excluding stock-based compensation expense)(3)
33,073 11,105 
Other segment items(4)
2,028 403 
Segment Adjusted EBITDA
$16,818 $26,449 43,267 
Reconciling items to consolidated loss before income taxes
Corporate expenses and other(5)
(31,912)
Elimination of intersegment Adjusted EBITDA(1)
64 
Depreciation, depletion and amortization(89,267)
Interest expense, net(31,481)
Stock-based compensation expense(30,007)
Initial start-up costs
(3,339)
Transaction-related and other costs(6)
(35,965)
Accretion of asset retirement and environmental obligations(1,490)
Loss on environmental obligation
(259)
Loss on disposals of long-lived assets, net(466)
Other income, net63,081 
Loss before income taxes
$(117,774)
Segment capital expenditures$92,249 $79,772 $172,021 
Other capital expenditures(7)
354 
Total capital expenditures for the year ended December 31, 2025
$172,375 
(1)Relates to NdPr oxide sales made by the Materials segment to the Magnetics segment.
(2)The primary difference between this significant segment expense and “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Company’s Consolidated Statements of Operations relates to stock-based compensation, which as disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” was $6.9 million for the year ended December 31, 2025. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(3)The primary differences between this significant segment expense and “Selling, general and administrative” within the Company’s Consolidated Statements of Operations relates to stock-based compensation and unallocated corporate costs, which are included in Corporate expenses and other in the table above. As disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” the total stock-based compensation expense included in “Selling, general and administrative” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2025, was $22.2 million. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(4)Principally relates to expenses included in “Advanced projects and development” within the Company’s Consolidated Statements of Operations.
(5)Corporate expenses and other represents costs incurred at the corporate level that are not allocated to the operating segments, specifically relating to executive compensation, investor relations, other corporate costs, and unallocated shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. “Corporate expenses and other” is included in the table above to reconcile the total of Segment Adjusted EBITDA to the Company’s consolidated loss before income taxes.
(6)Pertains to legal, consulting, and advisory services, and other costs associated with specific matters or transactions, including $12.7 million of costs incurred in association with the DoW transactions, $11.9 million of costs associated with a construction-related litigation matter and $7.4 million of costs incurred to secure financing.
(7)Includes amounts not allocated to the reportable segments (primarily related to corporate).
For the year ended December 31, 2024
(in thousands)MaterialsMagneticsTotal
Revenue from external customers
$203,855 $— $203,855 
Total consolidated revenues$203,855 
Significant segment expenses:
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(1)
188,894 — 
Selling, general and administrative (excluding stock-based compensation expense)(2)
27,655 8,441 
Other segment items(3)
1,454 3,783 
Segment Adjusted EBITDA$(14,148)$(12,224)(26,372)
Reconciling items to consolidated loss before income taxes
Corporate expenses and other(4)
(23,796)
Depreciation, depletion and amortization(78,057)
Interest expense, net(23,010)
Stock-based compensation expense(23,183)
Initial start-up costs(5,303)
Transaction-related and other costs(8,367)
Accretion of asset retirement and environmental obligations(929)
Loss on environmental obligation(1,998)
Loss on disposals of long-lived assets, net(1,421)
Gain on early extinguishment of debt52,911 
Other income, net46,178 
Loss before income taxes$(93,347)
Segment capital expenditures$106,677 $79,741 $186,418 
Total capital expenditures for the year ended December 31, 2024
$186,418 
(1)The primary difference between this significant segment expense and “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Company’s Consolidated Statements of Operations relates to stock-based compensation, which as disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” was $3.3 million for the year ended December 31, 2024. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(2)The primary differences between this significant segment expense and “Selling, general and administrative” within the Company’s Consolidated Statements of Operations relates to stock-based compensation and unallocated corporate costs, which are included in “Corporate expenses and other” in the table above. As disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” the total stock-based compensation expense included in “Selling, general and administrative” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2024, was $19.1 million. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(3)Principally relates to expenses included in “Advanced projects and development” within the Company’s Consolidated Statements of Operations.
(4)Corporate expenses and other represents costs incurred at the corporate level that are not allocated to the operating segments, specifically relating to executive compensation, investor relations, other corporate costs, and unallocated shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. “Corporate expenses and other” is included in the table above to reconcile the total of Segment Adjusted EBITDA to the Company’s consolidated loss before income taxes.
For the year ended December 31, 2023
(in thousands)MaterialsMagneticsTotal
Revenue from external customers
$253,445 $— $253,445 
Total consolidated revenues$253,445 
Significant segment expenses:
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(1)
88,656 — 
Selling, general and administrative (excluding stock-based compensation expense)(2)
32,164 3,925 
Other segment items(3)
2,233 2,597 
Segment Adjusted EBITDA$130,392 $(6,522)123,870 
Reconciling items to consolidated income before income taxes
Corporate expenses and other(4)
(21,368)
Depreciation, depletion and amortization(55,709)
Interest expense, net(5,254)
Stock-based compensation expense(25,236)
Initial start-up costs(20,607)
Transaction-related and other costs(11,435)
Accretion of asset retirement and environmental obligations(908)
Loss on disposals of long-lived assets, net(6,326)
Other income, net56,048 
Income before income taxes$33,075 
Segment capital expenditures$164,287 $95,463 $259,750 
Other capital expenditures(5)
2,147 
Total capital expenditures for the year ended December 31, 2023
$261,897 
(1)The primary difference between this significant segment expense and “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Company’s Consolidated Statements of Operations relates to stock-based compensation, which as disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” was $3.9 million for the year ended December 31, 2023. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(2)The primary differences between this significant segment expense and “Selling, general and administrative” within the Company’s Consolidated Statements of Operations relates to stock-based compensation and unallocated corporate costs, which are included in “Corporate expenses and other” in the table above. As disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” the total stock-based compensation expense included in “Selling, general and administrative” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2023, was $20.5 million. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(3)Principally relates to expenses included in “Advanced projects and development” within the Company’s Consolidated Statements of Operations.
(4)Corporate expenses and other represents costs incurred at the corporate level that are not allocated to the operating segments, specifically relating to executive compensation, investor relations, other corporate costs, and unallocated shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. “Corporate expenses and other” is included in the table above to reconcile the total of Segment Adjusted EBITDA to the Company’s consolidated income before income taxes.
(5)Includes amounts not allocated to the reportable segments (primarily related to corporate).
v3.25.4
SUPPLEMENTAL CASH FLOW INFORMATION
 12 Months Ended
Dec. 31, 2025
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]  
SUPPLEMENTAL CASH FLOW INFORMATION SUPPLEMENTAL CASH FLOW INFORMATION
Supplemental cash flow information and non-cash investing and financing activities were as follows:
For the year ended December 31,
(in thousands)202520242023
Supplemental cash flow information:
Cash paid for interest, net of amounts capitalized
$23,097 $12,127 $2,059 
Cash payments (refunds) related to income taxes, net - federal(1)
$(23,460)$— $22,170 
Cash payments (refunds) related to income taxes, net - state$138 $870 $(2,065)
Change in construction payables and accrued construction costs$34,060 $(16,692)$18,086 
Supplemental non-cash investing and financing activities:
Property, plant and equipment acquired with equipment notes$27,029 $— $— 
Operating right-of-use assets obtained in exchange for lease liabilities$6,917 $36 $7,690 
Issuance of Series A Preferred Stock in exchange for PPA Upfront Asset$118,998 $— $— 
Issuance of Warrant in exchange for PPA Upfront Asset$75,142 $— $— 
Issuance of Samarium Project Loan in exchange for PPA Upfront Asset$24,460 $— $— 
Excise tax obligation related to repurchases of common stock$— $1,979 $— 
Increase in estimates of asset retirement costs
$— $1,289 $— 
2026 Notes retired in Debt Exchange$— $142,301 $— 
2030 Notes issued in Debt Exchange$— $115,293 $— 
Common stock issued in exchange for financial advisory services$— $3,737 $— 
Common stock issued to acquire intangible asset$— $— $8,963 
(1)The year ended December 31, 2024, excludes the receipt of $19.4 million related to the 45X Credit claimed on the Company’s 2023 federal tax return, as the 45X Credit is not within the scope of ASC 740. See Note 17, “Government Grants,” for additional information.
v3.25.4
Insider Trading Arrangements
 3 Months Ended
Dec. 31, 2025
shares
Trading Arrangements, by Individual  
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
Ryan Corbett [Member]  
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
On December 16, 2025, Ryan Corbett, the Company’s Chief Financial Officer, adopted a Rule 10b5-1 trading arrangement intended to satisfy the affirmative defense of Rule 10b5-1(c) for the sale of up to 76,000 shares of the Company’s common stock, subject to certain conditions, from March 17, 2026, through October 30, 2026.
Name Ryan Corbett
Title Chief Financial Officer
Rule 10b5-1 Arrangement Adopted true
Adoption Date December 16, 2025
Expiration Date October 30, 2026
Aggregate Available 76,000
Elliot D. Hoops [Member]  
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
On November 20, 2025, Elliot Hoops, the Company’s General Counsel and Secretary, adopted a Rule 10b5-1 trading arrangement intended to satisfy the affirmative defense of Rule 10b5-1(c) for the sale of up to 107,486 shares of the Company’s common stock, subject to certain conditions, from March 16, 2026, through March 31, 2027.
Name Elliot Hoops
Title General Counsel and Secretary
Rule 10b5-1 Arrangement Adopted true
Adoption Date November 20, 2025
Expiration Date March 31, 2027
Aggregate Available 107,486
v3.25.4
Insider Trading Policies and Procedures
 12 Months Ended
Dec. 31, 2025
Insider Trading Policies and Procedures [Line Items]  
Insider Trading Policies and Procedures Adopted true
v3.25.4
Cybersecurity Risk Management and Strategy Disclosure
 12 Months Ended
Dec. 31, 2025
Cybersecurity Risk Management, Strategy, and Governance [Line Items]  
Cybersecurity Risk Management Processes Integrated [Flag] true
Cybersecurity Risk Management Processes Integrated [Text Block] As part of the Company’s overall risk assessment process, the enterprise risk management framework considers cybersecurity risk alongside other company risks. The Company’s internal audit department collaborates with the Company’s information technology department to gather insights for assessing, identifying and managing cybersecurity threat risks, their severity, and potential mitigations.
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag] true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag] false
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] The Company’s Cybersecurity Incident Response Committee (the “CIRC”), which is comprised of the Company’s CTO, Chief Financial Officer, General Counsel, Chief Accounting Officer, and Vice President of Internal Audit, meets periodically and more often, as needed, in the event cybersecurity incidents are identified.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block] The Company’s CTO provides periodic reports to the Audit Committee of the Company’s Board of Directors, as well as the CIRC, as appropriate. These periodic reports include updates on the Company’s cyber risks and threats, the status of projects to strengthen its information security systems, assessments of the information security program, and the emerging threat landscape.
Cybersecurity Risk Role of Management [Text Block] The CTO leads the information technology department, which is responsible for enterprise-wide cybersecurity strategy, policy, standards, architecture, and processes.
Cybersecurity Risk Management Positions or Committees Responsible [Flag] true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block] The Company’s information security program is managed by a dedicated Chief Technology Officer (“CTO”)
Cybersecurity Risk Management Expertise of Management Responsible [Text Block] who has over 25 years of professional experience within information technology roles, including 15 years of security consulting experience.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block] The Company’s CTO provides periodic reports to the Audit Committee of the Company’s Board of Directors, as well as the CIRC, as appropriate.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] true
v3.25.4
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)
 12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Basis of Presentation The Consolidated Financial Statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”), with the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”), and are presented in U.S. dollars.
v3.25.4
SIGNIFICANT ACCOUNTING POLICIES (Policies)
 12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Principles of Consolidation The Consolidated Financial Statements include the accounts of MP Materials Corp. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Concentration of Risk Financial instruments that potentially subject the Company to credit risk consist principally of cash, cash equivalents and short-term investments, and receivables from customers. The Company believes that its credit risk is limited because the Company’s current contracts are with companies that have a reliable payment history. The Company does not believe that it is exposed to any significant risks related to its cash accounts, money market funds, or short-term investments.
Concentration of Customer Risk: The concentration of customer risk arises when a significant portion of the Company’s revenue is generated from a small group of customers. Reduction of orders, delay of payments, or termination of contracts by these key customers could have a significant negative effect on the Company’s results of operations and cash flows. The Company’s revenue is derived from sales of rare earth products and, historically, from sales of rare earth concentrate to China, which ceased in July 2025 to align with the terms of the DoW Transaction Agreements. Rare earth concentrate is not quoted on any major commodities market or exchange, and demand is currently constrained to a relatively limited number of refiners, the majority of which are based in China.
For the year ended December 31, 2025, Customers A and B in the Materials segment accounted for 30% and 23% of the Company’s total revenue, respectively; Customer C, primarily in the Magnetics segment, accounted for 31% of the Company’s total revenue. For the year ended December 31, 2024, Customers B and A in the Materials segment accounted for 78% and 20% of the Company’s total revenue, respectively. For the year ended December 31, 2023, Customer B in the Materials segment accounted for 96% of the Company’s total revenue.
Use of Estimates The preparation of the Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities, (ii) the disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements, and (iii) the reported amounts of revenues and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions relate to the useful lives and recoverability of long-lived assets (such as the effects of mineral reserves and cash flows from operating the mine in determining the life of the mine); government grants; investment tax credits; the valuation allowance of deferred tax assets; asset retirement and environmental obligations; determining the net realizable value of inventories; and estimating the Company’s expected pattern of economic benefit of the PPA Upfront Asset (as defined below). Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Accordingly, actual results may differ from those estimates.
Segment Reporting Accounting Standards Codification (“ASC”) 280, “Segment Reporting,” (“ASC 280”) establishes standards for entities on how to report information about operating segments on a basis consistent with an entity’s internal organizational structure as well as information about an entity’s products and services, the geographical areas in which it operates and its major customers. Operating segments are defined as components of an enterprise engaged in business activities from which it may recognize revenues and incur expenses, about which discrete financial information is available and evaluated regularly by the chief operating decision maker (“CODM”), or decision-making group, in deciding how to allocate resources and in assessing performance.
Cash and Cash Equivalents Cash and cash equivalents consist of all cash balances and highly liquid investments, including commercial paper, certificates of deposit, and U.S. treasury and agency securities, with a maturity of three months or less at the time of purchase.
Marketable Securities
The Company’s investments in U.S. treasury and agency securities, commercial paper, and certificates of deposit have been classified and accounted for as available-for-sale securities and the Company re-evaluates the classification each reporting period. The Company classifies its available-for-sale securities that do not otherwise meet the requirements to be accounted for as cash equivalents as either current or non-current based on each instrument’s underlying contractual maturity date as well as the Company’s expectations of sales and redemptions within the next twelve months. See Note 4, “Cash, Cash Equivalents and Investments,” for additional information.
Available-for-sale securities are recorded at fair value each reporting period. For unrealized losses in securities that the Company intends to hold and will not more likely than not be required to sell before recovery, the Company further evaluates whether declines in fair value below amortized cost are due to credit or non-credit related factors. The Company considers credit related impairments to be changes in value that are driven by a change in the creditor’s ability to meet its payment obligations and records an allowance and recognizes a corresponding loss when the impairment is incurred.
Unrealized non-credit related losses and unrealized gains are reported, net of income taxes, in “Accumulated other comprehensive income” within the Company’s Consolidated Balance Sheets, until realized. Realized gains and losses are determined based on the specific identification method and are reported in “Other income, net” within the Company’s
Consolidated Statements of Operations upon realization. Premiums and discounts are amortized or accreted over the life of the related available-for-sale security as an adjustment to yield using the straight-line method. Interest income is recognized when earned. These amounts are reported in “Other income, net” within the Company’s Consolidated Statements of Operations.
Trade Accounts Receivable Trade accounts receivable pertain to receivables arising from contracts with customers and do not bear interest. The Company evaluates its estimate of expected credit losses based on historical experience and current economic conditions for each portfolio of customers, though at present, the amounts are concentrated among a limited number of customers.
Inventories Inventories consist of raw materials, supplies, mined ore stockpiles, work in process, and finished goods. Raw materials and supplies consist of spare parts, reagent chemicals, maintenance supplies, packaging materials and other consumables used in the production of rare earth products and magnetic precursor products. Mined ore stockpiles represent bastnaesite ore that has been mined and stockpiled for future processing. Work in process consists of bastnaesite ore and separated rare earth products in various stages of the production process, as well as finished and packaged NdPr oxide shipped to tollers for processing into NdPr metal. Work in process also includes packaged bastnaesite concentrate that has been stockpiled for future processing into separated rare earth products, including quantities which the Company elected to designate as NdPr Products for purposes of the PPA (as such terms are defined in Note 3, “Public-Private Partnership with U.S. Department of War”). Finished goods primarily consist of packaged NdPr oxide and NdPr metal (including quantities tolled) that are ready for sale. Raw materials, mined ore stockpiles, work in process, and finished goods are carried at weighted average cost. Supplies are carried at moving average cost. Certain products, principally mined ore stockpiles and bastnaesite concentrate, that are not expected to be processed within the next twelve months, and raw materials and spare parts that are not expected to be consumed within the next twelve months, are classified as non-current.
Inventory cost includes all costs directly attributable to the manufacturing process, including labor, raw materials, and an appropriate portion of production overhead costs, including depreciation and depletion, based on normal capacity of the production facilities. In periods when it is determined that the Company’s production facilities are operating below normal capacity levels, overhead costs are not included in inventory, and are instead directly recorded to “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” or “Depreciation, depletion and amortization” within the Company’s Consolidated Statements of Operations.
The Company evaluates the carrying amount of inventory each reporting period, considering recent market prices, slow-moving items, obsolescence, excess inventory levels and other factors. All inventories are carried at the lower of cost or net realizable value (“NRV”). NRV represents the estimated selling price of the product less reasonably predictable costs of completion, disposal, and transportation. The PPA provides contractual price protection for designated NdPr Products. This ensures the Company will receive at least the price floor for such products. The Company includes future estimated PPA income in the NRV of certain inventories. Write-downs are recognized for the excess of a product’s cost over its NRV.
Property, Plant and Equipment Property, plant and equipment are recorded at cost and depreciated over their useful lives. Expenditures for new property, plant and equipment and improvements that extend the useful life or functionality of the assets are recorded at their cost of acquisition or construction. Depreciation on property, plant and equipment is recognized on a straight-line basis over their estimated useful lives, as follows:
Years
Land improvements
10-25
Buildings and building improvements
10-40
Machinery and equipment
3-20
Assets under construction include costs directly attributable to the construction or development of long-lived assets. These costs may include labor and employee benefits associated with the construction of the asset, site preparation, permitting, engineering and design, installation and assembly, procurement, insurance, legal, initial commissioning, and interest on borrowings to finance the construction of the assets. Depreciation is not recorded on the related assets until they are ready for their intended use. Repair and maintenance costs that do not extend the useful life of an asset are expensed as incurred. Gains and losses arising from the sale or disposal of property, plant and equipment are determined as the difference between the proceeds from sale or disposal and the carrying amount of the asset, and are included, along with demolition costs, in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations.
Property, plant and equipment primarily relate to the Company’s open-pit mine and processing and separations facility at Mountain Pass as well as building and machinery associated with the Company’s Independence Facility, including electrolysis cells, strip casters, and sintering furnaces. In addition to the mine pit, Mountain Pass includes a crusher and mill/flotation plant, mineral recovery and separation plants, tailings processing and storage facilities, product finishing facilities, on-site evaporation ponds, a combined heat and power plant, water treatment plant, a chlor-alkali facility, as well as laboratory facilities to support research and development activities, offices, warehouses and support infrastructure.
Mineral Rights The Company capitalizes costs for acquiring and leasing mining properties and expenses costs to maintain mineral rights as incurred. Depletion on mineral rights is recognized on a straight-line basis over the estimated remaining useful life of the mine, which was approximately 28 years as of December 31, 2025. The Company determined that the straight-line method of depletion appropriately captures the estimated economic costs of extracting the minerals of the mine across its estimated useful life, and aligns with the benefit obtained from the depletion of the asset consistent with the current mine plan. Mineral rights are classified as a component of “Property, plant and equipment, net” within the Company’s Consolidated Balance Sheets.
PPA Upfront Asset The PPA is a price floor protection agreement that conveys a contingent right for the Company to receive cash from the DoW and also imposes a contingent obligation for the Company to deliver cash to the DoW in the future as described in Note 3, “Public-Private Partnership with U.S. Department of War.” Given the contractual cash flows, the right to the price floor protection granted by the DoW under the PPA (the “PPA Upfront Asset”) was determined to be a financial instrument. The initially recognized amount of the PPA Upfront Asset results from the difference between the fair value of the other instruments exchanged with the DoW and the cash consideration received from the DoW. The PPA Upfront Asset is presented as “Price protection agreement upfront asset, net” in non-current assets within the Company’s Consolidated Balance Sheets. The Company did not elect to apply the fair value option to the PPA Upfront Asset on a recurring basis. Beginning October 1, 2025, the PPA’s commencement date, the PPA Upfront Asset is being amortized over the Company’s expected pattern of economic benefit from the PPA, with the expense recognized within “Depreciation, depletion and amortization” in the Company’s Consolidated Statements of Operations. Reassessment of the PPA Upfront Asset’s useful life, pattern of economic benefit as well as impairment considerations is consistent with the Company’s existing policies for long-lived assets.
Operating Leases The Company determines if an arrangement is, or contains, a lease at contract inception. In some cases, the Company has determined that its lease arrangements include both lease and non-lease components. The Company has elected to use a practical expedient to account for each separate lease component and its associated non-lease components as a single lease component for the majority of its asset classes. The Company recognizes right-of-use (“ROU”) assets and lease liabilities upon commencement for all leases with a lease term greater than 12 months. The Company has elected to use a practical expedient to not recognize leases with a lease term of 12 months or less in the Consolidated Balance Sheets for all of its asset classes. These short-term leases are expensed on a straight-line basis over the lease term.ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the commencement date of the lease based on the present value of lease payments over the lease term. When the rate implicit in the lease cannot be readily determined, the Company utilizes its incremental borrowing rate in determining the present value of the future lease payments. Lease liabilities are accreted each period and reduced for payments. The ROU asset also includes other adjustments, such as for the effects of lease prepayments, initial lease costs, or lease incentives received. The lease term may include periods covered by options to extend or terminate the lease when it is either reasonably certain that the Company will exercise a renewal option, or reasonably certain it will not exercise an early termination option. Lease expense is recognized on a straight-line basis over the lease term. Variable lease payments not included in the lease liability are expensed as incurred unless such costs are capitalized as part of another asset (e.g., inventory). Additionally, ROU assets are subject to impairment testing whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. If the carrying amounts of ROU assets exceed their fair value, the excess amount is recognized as an impairment.
Revenue from Contract with Customer In accordance with ASC Subtopic 340-40, the Company evaluates whether or not certain costs incurred to obtain and fulfill contracts with customers should be capitalized. Capitalized contract fulfillment costs that are not within the scope of another ASC Topic are capitalized if they: (1) relate directly to an existing or specific anticipated contract, (2) generate or enhance resources that will be used to satisfy future performance obligations, and (3) are expected to be recovered. Capitalized costs are presented within “Other non-current assets” within the Company’s Consolidated Balance Sheets and are amortized on a systematic basis that is consistent with the pattern of transfer of the goods or services to which the asset relates.Contract liabilities, commonly referred to as deferred revenue, represent the Company’s obligation to transfer goods or services to a customer for which the Company has received consideration in advance of such transfer. Deferred revenue decreases as revenue is recognized from the satisfaction of the related performance obligations. Amounts expected to be recognized as revenue during the 12-month period after the balance sheet date are classified as current deferred revenue with the remainder classified as non-current in the Company’s Consolidated Balance Sheets.
Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. In estimating undiscounted cash flows, assets are grouped at the lowest level for which there are identifiable cash flows that are largely independent of undiscounted cash flows from other asset groups. The Company’s estimates of undiscounted cash flows are based on numerous assumptions, and it is possible that actual cash flows may differ significantly from estimates, as actual produced reserves, prices, commodity-based and other costs, and closure costs are each subject to significant risks and uncertainties. The estimated undiscounted cash flows used to assess recoverability of long-lived assets and to measure the fair value of the Company’s operations are derived from current business plans, which are developed using short-term price forecasts reflective of the current price environment and the Company’s projections for long-term average prices. In addition to short- and long-term price assumptions, other assumptions include estimates of production costs; proven and probable mineral reserve estimates, including the timing and cost to develop and produce the reserves; value beyond proven and probable estimates; and estimated future closure costs.
If the carrying amount of the long-lived asset or asset groups is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques, including discounted cash flow models, quoted market values, and third-party independent appraisals, based on the approach the Company believes a market participant would use.
Equity Method Investments Investments in equity securities are accounted for under the equity method if the Company has the ability to exercise significant influence, but not control, over an investee’s operating and financial policies. Judgment regarding the level of influence includes considering key factors such as the Company’s ownership interest, representation on the board of directors, participation in policy-making decisions and material intra-entity transactions. Under the equity method, an investment’s carrying amount is adjusted for the Company’s share of the investee’s net income or loss (including other comprehensive income or loss), amortization/accretion of certain basis differences (if any), capital contributions to and distributions from an investee, as well as any other-than-temporary impairments. The Company records its share of an equity method investment’s net income or loss on a one-quarter lag due to the timing of when an investee’s financial statements become available. The Company evaluates material events occurring during the one-quarter lag to determine whether the effects of such events should be reflected or disclosed within the Company’s Consolidated Financial Statements. For intra-entity transactions between the Company and its equity method investee, the Company eliminates its share of profits and losses until realized by the Company or investee. Such elimination is recorded as an adjustment of the carrying amount of the equity method investment.
Intangible Assets Indefinite-lived intangible assets are tested annually for impairment, or more frequently if events or changes in circumstances indicate that it is more likely than not that the assets are impaired. If the carrying amounts of the indefinite-lived intangible assets exceed their fair value, the excess amount is recognized as an impairment. Intangible assets that have a definite life are amortized on a straight-line basis over their estimated useful lives to reflect the expected pattern of economic benefits consumed. The Company reviews the carrying amount of its amortizing intangible assets for possible impairment whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. If the carrying amounts of the amortizing intangible assets exceed their fair value, the excess amount is recognized as an impairment. Once an impairment of an intangible asset has been recorded, it cannot be reversed.
Asset Retirement Obligations The Company recognizes asset retirement obligations (“ARO”) for estimated costs of legally and contractually required closure, dismantlement, and reclamation activities associated with Mountain Pass. ARO are initially recognized at their estimated fair value in the period in which the obligation originates. Fair value is based on the expected timing of reclamation activities, cash flows to perform activities, amount and uncertainty associated with the cash flows, including adjustments for a market risk premium, and discounted using a credit-adjusted risk-free rate. The liability is accreted over time through periodic charges to earnings and reduced as reclamation activities occur with differences between estimated and actual amounts recognized as adjustments to operating expenses. Accretion of ARO is included in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations.Subsequent increments in expected undiscounted cash flows are measured at their discounted values using updated estimates of the Company’s credit-adjusted risk-free rate applied to the increment only. Subsequent decrements in expected undiscounted cash flows are reduced based on the weighted-average credit-adjusted risk-free rate associated with the obligation. When increments and decrements are caused by a change in the estimated timing of settlement, the Company treats the increase in cash flows in the year of the updated estimate as an increment and the decrease in cash flows in the original year as a decrement. Associated asset retirement costs, including the effect of increments and decrements, are recognized as adjustments to the related asset’s carrying amount and depreciated over the related asset’s remaining useful life. If a decrement is greater than the carrying amount of the related asset, the difference is recognized as a reduction to depreciation expense.
Environmental Obligations The Company has certain environmental remediation obligations that primarily relate to groundwater monitoring activities. Estimated remediation costs are accrued based on management’s best estimate at the end of each reporting period of the costs expected to be incurred to settle the obligation when those amounts are probable and estimable. If the cost can only be estimated as a range of possible amounts with no point in the range being more likely, then the minimum of the range is accrued. Such cost estimates may include ongoing care, maintenance and monitoring costs associated with remediation activities. Changes in remediation estimates are reflected in earnings in the period the estimate is revised. Remediation costs included in environmental obligations are discounted to their present value when payments are readily estimable, and are discounted using a risk-free rate, which the Company derives from U.S. Treasury yields. Accretion of environmental obligations is included in “Other operating costs and expenses” within the Company’s Consolidated Statements of Operations.
Convertible Debt and Embedded Derivatives The Company accounts for its convertible debt in accordance with ASC Subtopic 470-20, “Debt with Conversion and Other Options” (“ASC 470-20”), whereby the convertible instrument is initially accounted for as a single unit of account, unless it contains a derivative that must be bifurcated from the host contract in accordance with ASC Topic 815, “Derivatives and Hedging” (“ASC 815”) or the substantial premium model in ASC Subtopic 470-20 applies. When it is determined that an embedded derivative is required to be bifurcated, the Company recognizes the bifurcated embedded derivative, measured at fair value, as a separate derivative asset or liability upon initial recognition and in subsequent periods at fair value with changes in fair value included in profit or loss each reporting period. Changes in the fair value each reporting period are included in “Other income, net” within the Company’s Consolidated Statements of Operations. Where the substantial premium model applies, the premium is recorded in “Additional paid-in capital” in “Stockholders’ equity” within the Company’s Consolidated Balance Sheets.
Capped Call Options The Company’s Capped Call Options cover the aggregate number of shares of its common stock that initially underlie the 2030 Notes (as such terms are defined in Note 10, “Debt Obligations”) that were issued in March 2024, and generally reduce potential dilution to the Company’s common stock upon the conversion of the 2030 Notes and/or offset any cash payments the Company may make in excess of the principal amount of the converted 2030 Notes, as the case may be, with such reduction and/or offset subject to a cap, based on the cap price of the Capped Call Options.The Company determined that the Capped Call Options meet the definition of a freestanding derivative under ASC 815 but are not required to be separately accounted for as a derivative as they meet the indexation and equity classification scope exception outlined in ASC 815. Accordingly, the Company recognized the cash paid to enter into the Capped Call Options contract by recording an entry to “Additional paid-in capital” in “Stockholders’ equity” within the Company’s Consolidated Balance Sheets. The Capped Call Options will not be remeasured each reporting period.
Debt Discount and Debt Issuance Costs Debt discount represents the difference between the net proceeds received and the debt’s fair value at the time of issuance. Debt issuance costs include incremental third-party costs directly related to the debt issuance. For debt instruments other than the Company’s Revolving Credit Facility (as defined in Note 10, “Debt Obligations”), debt discount and debt issuance costs are recorded as a direct reduction of the carrying amount of the associated debt instrument and are amortized to interest expense using the effective interest method over the contractual term of the underlying indebtedness. Debt issuance costs related to the Company’s Revolving Credit Facility are recorded in “Other non-current assets” within the Company’s Consolidated Balance Sheets and are amortized to interest expense on a straight-line basis over the term of the Revolving Credit Facility arrangement.
Commitments and Contingencies Liabilities for loss contingencies arising from claims, assessments, litigation, fines and penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. If a loss contingency is not probable or reasonably estimable, disclosure of the contingency and estimated range of loss, if determinable, is made in the financial statements when it is at least reasonably possible that a material loss could be incurred. Legal costs incurred in connection with loss contingencies are expensed as incurred.
Series A Preferred Stock The Company’s Series A Preferred Stock is classified as redeemable preferred stock (i.e., temporary equity) outside of stockholders’ equity within the Company’s Consolidated Balance Sheets due to certain redemption rights not solely within the Company’s control. The purpose of this classification is to convey that such a security may not be permanently part of equity and could result in a demand for cash, securities or other assets of the entity in the future. All financial instruments are evaluated for embedded derivative features by analyzing each feature against the nature of the host instrument (e.g., more equity-like or debt-like). Features identified as freestanding instruments or bifurcated embedded derivatives that are material are recognized separately as a derivative asset or liability. The Company evaluated the Series A Preferred Stock and determined that its nature is that of an equity-host with no embedded derivatives requiring bifurcation. The Company initially recognized the Series A Preferred Stock at its relative fair value, net of allocated issuance costs.At each reporting period, the Company reassesses whether the Series A Preferred Stock is (i) currently redeemable or (ii) probable of becoming redeemable in the future. If the instrument meets either criterion, the Company will adjust the carrying amount to the estimated maximum redemption value (i.e., the redemption price). As of December 31, 2025, the Series A Preferred Stock was not redeemable, nor probable of becoming redeemable in the future. As such, the carrying amount of the Series A Preferred Stock was not adjusted to the maximum redemption value.
Warrants The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms. The assessment considers whether the warrants are freestanding financial instruments, meet the definition of a liability, and whether the warrants meet all of the requirements for equity classification, including whether the warrants are indexed to the Company’s own common stock. The Company analyzed the classification of its outstanding Warrant as of the date of issuance and as of December 31, 2025, and determined that such instrument met the criteria for equity classification.
Treasury Stock Treasury stock represents shares of the Company’s common stock that have been reacquired after having been issued and is accounted for under the cost method. Treasury stock is excluded from the Company’s outstanding shares and recorded as a reduction of “Stockholders’ equity” within the Company’s Consolidated Balance Sheets, unless the repurchased shares are immediately retired. Incremental direct costs to purchase treasury stock, such as excise taxes and commission fees, are included in the cost of the shares acquired.
Revenue Recognition The Company’s revenue comes from sales of rare earth products produced at Mountain Pass and sales of magnetic precursor products, including NdPr metal, produced at the Independence Facility. The Company recognizes revenue for the amount it expects to receive, which may include variable consideration and be reduced for amounts payable to a customer. Variable consideration is included in the Company’s expected sales price to the extent it is probable there will not be a significant reversal of previously recognized revenue. Revenue is recognized when control of the promised products is transferred to the customer, which generally occurs at the point in time the products are delivered to the agreed-upon shipping point. To determine when control of the products transfers to a customer, the Company evaluates the point in time the customer bears the risk of loss and has the ability to direct the use of and obtain substantially all of the remaining benefits from the products. Revenue from product sales is recorded net of taxes collected from customers that are remitted to governmental authorities.Periodically, the Company receives requests from its customers to temporarily hold purchased products at the Company’s facilities under a bill-and-hold arrangement. The Company recognizes revenue under these arrangements only when there is a substantive reason for the agreement, the ordered goods are identified separately as belonging to the customer, the goods are currently ready for physical transfer to the customer, and the Company does not have the ability to use the product or to direct it to another customer. Assuming these criteria are met, revenue is recognized at the point in time control of the product transfers to the customer, which may be upon completion of product manufacture or delivery to an agreed location.
Price Protection Agreement Income or Expense On a quarterly basis, beginning on the PPA’s commencement date and throughout the PPA’s 10-year term, the Company will have the right to receive cash from or an obligation to deliver cash to the DoW. The Company recognizes its rights or obligations as price protection agreement income or expense within the Company’s Consolidated Statements of Operations in the period in which the events giving rise to the right or obligation occur. Each quarterly period represents a distinct contractual period for which amounts receivable or payable are recognized as earned or incurred, respectively.
Government Grants Government grants represent benefits provided by federal, state, or local governments that are not subject to the scope of ASC Topic 740, “Income Taxes” (“ASC 740”). Government grants are initially estimated and recognized when there is reasonable assurance the conditions of the grant will be met, and the grant will be received. When a grant is related to the purchase or construction of a long-lived asset (considered asset-based grants), the funds received are recorded as a reduction to the related asset’s carrying amount, thereby reducing future depreciation expense. Alternatively, when a grant is related to an expense item (considered income-based grants), it is recognized as a reduction of expense to which the grant activity relates over the periods necessary to match the grant on a systematic basis to the costs that it is intended to compensate. The effect of a change in estimate is recognized in the period in which management concludes that it is no longer reasonably assured that (i) all of the grant conditions will be met or (ii) a portion of the grant will be received.
Stock-Based Compensation The cost of employee services received in exchange for an award of equity instruments is based on the grant-date fair value of the award. The Company accounts for forfeitures in the period in which they occur based on actual forfeitures.
Stock Awards contain service conditions, and their fair value equals the product of the Company’s stock price on the date of grant and the number of Stock Awards granted. Compensation cost for Stock Awards with graded vesting schedules is recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award were, in substance, multiple awards, which results in accelerated recognition of compensation cost.
Market-based PSUs include service and market conditions, and their fair value is determined using a Monte Carlo simulation technique. The Monte Carlo simulation requires the use of inputs and assumptions such as the grant-date closing stock price, expected volatility, correlation coefficient to relevant peer groups or indices, risk-free interest rate and dividend yield. Compensation cost for market-based PSUs with cliff vesting schedules is recognized on a straight-line basis over the requisite service period. Compensation cost for these awards is not adjusted based on the actual achievement of the market-based performance goals.
Performance-based PSUs include service and performance conditions, and their fair value equals the product of the Company’s stock price on the date of grant and the number of awards granted. Compensation cost for performance-based PSUs with cliff vesting schedules is recognized on a straight-line basis over the requisite service period if it is probable that a performance condition will be achieved. No compensation cost will be recognized for a performance condition that is not probable of being achieved. The Company re-evaluates at the end of each reporting period whether or not a performance condition is probable of being achieved. If, based on this re-evaluation, the Company estimates an increase in overall compensation cost, then the Company will recognize a cumulative catch-up of compensation cost in the period of the re-evaluation. Alternatively, if the Company estimates a decrease in overall compensation cost, the Company will not reverse compensation cost already recognized until achievement of the performance condition is estimated to be improbable.
Start-up Costs Costs associated with restarting an existing facility or commissioning a new facility, circuit or process of the Company’s production, manufacturing, or separations facilities prior to the achievement of commercial production, that do not qualify for capitalization, are expensed as incurred and considered start-up costs. Such costs may include certain salaries and wages, outside services, parts, training, and utilities, among other items, used or consumed directly in these start-up activities.
Earnings or Loss per Common Share Net income or loss attributable to common stock is computed using the two-class method when shares are issued that meet the definition of participating securities. The Company’s Series A Preferred Stock is a participating security because these shares contractually entitle their holders to potentially participate in dividends by way of the Special Payment (as defined and further described in Note 14, “Redeemable Preferred Stock”), but do not contractually require their holders to participate in the Company’s losses.
The two-class method is an earnings allocation formula that requires undistributed earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. During the periods when there is a net loss, no amounts of undistributed losses are allocated to the Company’s participating securities.
Basic earnings or loss per common share is computed by dividing net income or loss attributable to common stock by the weighted-average number of common shares outstanding during the period.
Diluted earnings or loss per common share is computed by dividing net income or loss attributable to common stock (the numerator) by the weighted-average number of common shares outstanding during the period (the denominator) using the treasury stock method, the if-converted method, or the two-class method, as applicable. The numerator is adjusted for the effects of changes in income available to common stock that arise from the assumed conversion of dilutive convertible securities. The denominator is adjusted for the effects of dilutive potential common shares outstanding.
Income Taxes and Valuation of Deferred Tax Assets The Company accounts for income taxes using the balance sheet method, recognizing certain temporary differences between the book basis of the liabilities and assets and the related income tax basis for such liabilities and assets. This method generates either a net deferred tax liability or asset for the Company, as measured by the statutory tax rates in effect. The Company derives a deferred tax expense or benefit by recording the change in either the net deferred tax liability or asset balance for the year. The Company’s policy, if it were to have uncertain tax positions, is to recognize interest and/or penalties related to unrecognized tax benefits as part of its income tax expense.An investment tax credit (“ITC”) represents a benefit provided by federal, state, or local governments to encourage an entity to invest in specific types of assets. An ITC is commonly calculated as a percentage of the investment cost of a qualifying asset and may be subject to the scope of ASC 740. The accounting for an ITC may depend upon certain factors, including whether or not the ITC is refundable and/or transferable. The Company elected to account for its nonrefundable, transferable ITCs under ASC 740. This type of ITC is initially estimated and recognized when the Company places into service a qualifying asset and determines that it will more-likely-than-not comply with the requirements to receive the ITC. Additionally, the Company elected to account for these ITCs under the deferral method whereby the Company will initially record such ITC as a deferred liability and subsequently recognize the ITC in the income statement as a reduction to income tax expense over the useful lives of the qualifying assets. As a result of the deferral method, the Company also elected to recognize immediately in income tax expense the deferred tax effect, net of any valuation allowance, as a result of such transaction.The Company’s deferred tax assets include certain future tax benefits. The Company records a valuation allowance against any portion of those deferred tax assets when it believes, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax asset will not be realized. The Company reviews the likelihood that the benefit of the deferred tax assets will be realized and the need for valuation allowances on a quarterly basis.
Certain categories of evidence carry more weight in the analysis than others based upon the extent to which the evidence may be objectively verified. The Company looks to the nature and severity of cumulative pretax losses (if any) in the current three-year period ending on the evaluation date, recent pretax losses and/or expectations of future pretax losses. Other factors considered in the determination of the probability of the realization of the deferred tax assets include, but are not limited to: earnings history; projected future financial and taxable income based upon existing reserves and long-term estimates of commodity prices; the duration of statutory carry forward periods; prudent and feasible tax planning strategies readily available that may alter the timing of reversal of the temporary difference; nature of temporary differences and predictability of reversal patterns of existing temporary differences; and the sensitivity of future forecasted results to commodity prices and other factors.
Concluding that a valuation allowance is not required is difficult when there is significant negative evidence which is objective and verifiable, such as cumulative losses in recent years. However, recent cumulative losses are not solely determinative of the need for a valuation allowance. The Company also considers all other available positive and negative evidence in its analysis.
Recently Issued Accounting Pronouncements Not Yet Adopted
Recently Issued Accounting Pronouncements Not Yet Adopted: Other than those listed below, there were no accounting pronouncements issued during the year ended December 31, 2025, that had or would be expected to have a material impact on the Company’s Consolidated Financial Statements and accompanying notes.
In December 2025, the FASB issued ASU No. 2025-10, “Government Grants—Accounting for Government Grants Received by Business Entities” (“ASU 2025-10”), to establish authoritative GAAP guidance for the recognition, measurement, and presentation of government grants received by business entities. The amendments define government grants, distinguish between grants related to assets and income, and provide criteria for when grants are recognized. Entities may elect either a deferred income approach or a cost accumulation approach for asset-related grants, while income-related grants are recognized systematically over the periods of related expenses. Additionally, ASU 2025-10 prescribes presentation options and requires disclosures about the nature, terms, and accounting policies for grants. ASU 2025-10 is effective for the Company’s fiscal years beginning after December 15, 2027, and may be applied prospectively or retrospectively. The Company is currently evaluating the effect of adopting ASU 2025-10 on its financial statements and disclosures.
In November 2024, the FASB issued ASU No. 2024-03, “Income Statement—Reporting Comprehensive Income Expense Disaggregation Disclosures” (“ASU 2024-03”), which amends ASC Topic 220, “Comprehensive Income,” to enhance the disclosure of expense information in the notes to the financial statements. ASU 2024-03 requires public business entities to disaggregate specified income statement expenses, such as purchases of inventory, employee compensation, depreciation, amortization, and depletion into detailed categories presented in a tabular format. Additionally, ASU 2024-03 mandates qualitative descriptions for expenses not separately disaggregated and annual disclosure of selling expenses and their definitions. ASU 2024-03 is effective for the Company’s fiscal years beginning after December 15, 2026, and interim periods beginning after December 15, 2027, and may be applied prospectively or retrospectively. The Company is currently evaluating the effect of adopting ASU 2024-03 on its disclosures.
In November 2024, the FASB issued ASU No. 2024-04, “Induced Conversions of Convertible Debt Instruments” (“ASU 2024-04”), which enhances guidance in ASC Topic 470, “Debt,” to improve consistency and relevance in accounting for induced conversions of convertible debt instruments. Specifically, ASU 2024-04 clarifies criteria for when settlements should be treated as induced conversions, requiring that inducement offers preserve the form and amount of consideration issuable under original conversion terms. ASU 2024-04 is effective for the Company’s fiscal years and interim periods within those fiscal years beginning after December 15, 2025, with early adoption permitted, and may be applied prospectively or retrospectively. The Company is currently evaluating the effect of adopting ASU 2024-04 on its financial statements and disclosures.
Reclassifications Certain amounts in prior periods have been reclassified to conform to the current year presentation.
v3.25.4
SIGNIFICANT ACCOUNTING POLICIES (Tables)
 12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Schedule of Estimated Useful Lives Depreciation on property, plant and equipment is recognized on a straight-line basis over their estimated useful lives, as follows:
Years
Land improvements
10-25
Buildings and building improvements
10-40
Machinery and equipment
3-20
The Company’s property, plant and equipment consisted of the following:
December 31,
(in thousands)20252024
Land and land improvements$43,422 $42,789 
Buildings and building improvements101,564 96,961 
Machinery and equipment756,202 662,333 
Assets under construction302,935 202,544 
Mineral rights438,395 438,395 
Property, plant and equipment, gross1,642,518 1,443,022 
Less: Accumulated depreciation and depletion(272,701)(191,526)
Property, plant and equipment, net$1,369,817 $1,251,496 
The Company’s depreciation and depletion expense, net of amounts capitalized into inventories, was as follows:
For the year ended December 31,
(in thousands)202520242023
Depreciation expense
$69,587 $63,558 $43,998 
Depletion expense
$6,724 $13,036 $11,067 
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR (Tables)
 12 Months Ended
Dec. 31, 2025
Government Assistance [Abstract]  
Schedule of Initial Amounts Recognized for DoW Transactions The following table presents the initially recognized amounts for the DoW Transactions:
(in thousands)Measured ValueAllocated Transaction CostsRecognized Amount
Consideration received:
Cash$550,000 $— $550,000 
PPA Upfront Asset218,600 2,502 221,102 
Total consideration received$768,600 $2,502 $771,102 
Consideration given:
Series A Preferred Stock$418,400 $(4,789)$413,611 
Warrant264,200 (3,024)261,176 
Samarium Project Loan86,000 (985)85,015 
Total consideration given$768,600 $(8,798)$759,802 
Schedule of Cash and Non-Cash Amounts Recognized for DoW Transactions
(in thousands)Cash ConsiderationNon-cash ConsiderationMeasured Value
Issued Instruments:
Series A Preferred Stock$299,402 $118,998 $418,400 
Warrant189,058 75,142 264,200 
Samarium Project Loan61,540 24,460 86,000 
Total consideration received for Issued Instruments$550,000 $218,600 $768,600 
Schedule of Price Protection Agreement, Upfront Asset
The PPA Upfront Asset within the Company’s Consolidated Balance Sheets consisted of the following:
December 31,
(in thousands)20252024
PPA Upfront Asset$221,102 $— 
Less: Accumulated amortization (11,434)— 
PPA Upfront Asset, net
$209,668 $— 
Schedule of Price Protection Agreement, Upfront Asset, Future Amortization Expense
The following table presents the estimated amortization expense for the PPA Upfront Asset as of December 31, 2025:
(in thousands)
Period:
2026$43,539 
202741,142 
202838,246 
202932,898 
203021,498 
Thereafter32,345 
Total$209,668 
v3.25.4
CASH, CASH EQUIVALENTS AND INVESTMENTS (Tables)
 12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Schedule of Available-for-Sale Debt Securities
The following table presents the Company’s cash, cash equivalents and short-term investments:
December 31, 2025December 31, 2024
(in thousands)Amortized Cost BasisUnrealized GainsUnrealized LossesEstimated Fair ValueAmortized Cost BasisUnrealized GainsUnrealized LossesEstimated Fair Value
Cash:
Demand deposits$16,536 $— $— $16,536 $1,889 $— $— $1,889 
Cash equivalents:
Money market funds748,322 — — 748,322 164,477 — — 164,477 
U.S. Treasury securities334,339 59 — 334,398 86,320 17 — 86,337 
Commercial paper48,762 7 — 48,769 29,731 8 — 29,739 
Certificates of deposit17,985 1 — 17,986 — — — — 
Total cash equivalents1,149,408 67 — 1,149,475 280,528 25 — 280,553 
Total cash and equivalents1,165,944 67 — 1,166,011 282,417 25 — 282,442 
Short-term investments:
U.S. agency securities— — — — 2,240 — — 2,240 
U.S. Treasury securities636,214 367 — 636,581 544,410 222 (12)544,620 
Commercial paper
21,767 4 — 21,771 16,661 6 — 16,667 
Certificates of deposit5,923 — — 5,923 4,897 2 — 4,899 
Total short-term investments663,904 371 — 664,275 568,208 230 (12)568,426 
Total cash, cash equivalents and short-term investments$1,829,848 $438 $— $1,830,286 $850,625 $255 $(12)$850,868 
Schedule of Cash and Cash Equivalents
The following table presents the Company’s cash, cash equivalents and short-term investments:
December 31, 2025December 31, 2024
(in thousands)Amortized Cost BasisUnrealized GainsUnrealized LossesEstimated Fair ValueAmortized Cost BasisUnrealized GainsUnrealized LossesEstimated Fair Value
Cash:
Demand deposits$16,536 $— $— $16,536 $1,889 $— $— $1,889 
Cash equivalents:
Money market funds748,322 — — 748,322 164,477 — — 164,477 
U.S. Treasury securities334,339 59 — 334,398 86,320 17 — 86,337 
Commercial paper48,762 7 — 48,769 29,731 8 — 29,739 
Certificates of deposit17,985 1 — 17,986 — — — — 
Total cash equivalents1,149,408 67 — 1,149,475 280,528 25 — 280,553 
Total cash and equivalents1,165,944 67 — 1,166,011 282,417 25 — 282,442 
Short-term investments:
U.S. agency securities— — — — 2,240 — — 2,240 
U.S. Treasury securities636,214 367 — 636,581 544,410 222 (12)544,620 
Commercial paper
21,767 4 — 21,771 16,661 6 — 16,667 
Certificates of deposit5,923 — — 5,923 4,897 2 — 4,899 
Total short-term investments663,904 371 — 664,275 568,208 230 (12)568,426 
Total cash, cash equivalents and short-term investments$1,829,848 $438 $— $1,830,286 $850,625 $255 $(12)$850,868 
Schedule of Interest and Investment Income
The Company’s interest and investment income, which is included in “Other income, net” within the Company’s Consolidated Statements of Operations, was as follows:
For the year ended December 31,
(in thousands)202520242023
Interest and investment income(1)
$52,015 $47,114 $55,637 
(1)Includes interest and investment income on the Company’s available-for-sale securities and other money market funds.
v3.25.4
INVENTORIES (Tables)
 12 Months Ended
Dec. 31, 2025
Inventory Disclosure [Abstract]  
Current Inventories
The Company’s inventories consisted of the following:
December 31,
(in thousands)20252024
Raw materials and supplies, including spare parts
$56,491 $48,400 
Mined ore stockpiles
23,795 31,142 
Work in process
51,652 14,447 
Finished goods
39,622 13,916 
Total current inventories171,560 107,905 
Add: Non-current portion(1)
80,539 19,031 
Total inventories$252,099 $126,936 
(1)Primarily represents stockpiles of mined ore, bastnaesite concentrate and lanthanum that are not expected to be processed or consumed within the next 12 months. The ore, concentrate and lanthanum amounts were $24.1 million, $31.7 million and $10.5 million as of December 31, 2025, respectively, and $12.3 million, zero and zero as of December 31, 2024, respectively.
Noncurrent Inventories
The Company’s inventories consisted of the following:
December 31,
(in thousands)20252024
Raw materials and supplies, including spare parts
$56,491 $48,400 
Mined ore stockpiles
23,795 31,142 
Work in process
51,652 14,447 
Finished goods
39,622 13,916 
Total current inventories171,560 107,905 
Add: Non-current portion(1)
80,539 19,031 
Total inventories$252,099 $126,936 
(1)Primarily represents stockpiles of mined ore, bastnaesite concentrate and lanthanum that are not expected to be processed or consumed within the next 12 months. The ore, concentrate and lanthanum amounts were $24.1 million, $31.7 million and $10.5 million as of December 31, 2025, respectively, and $12.3 million, zero and zero as of December 31, 2024, respectively.
v3.25.4
PROPERTY, PLANT AND EQUIPMENT (Tables)
 12 Months Ended
Dec. 31, 2025
Property, Plant and Equipment [Abstract]  
Property, plant and equipment Depreciation on property, plant and equipment is recognized on a straight-line basis over their estimated useful lives, as follows:
Years
Land improvements
10-25
Buildings and building improvements
10-40
Machinery and equipment
3-20
The Company’s property, plant and equipment consisted of the following:
December 31,
(in thousands)20252024
Land and land improvements$43,422 $42,789 
Buildings and building improvements101,564 96,961 
Machinery and equipment756,202 662,333 
Assets under construction302,935 202,544 
Mineral rights438,395 438,395 
Property, plant and equipment, gross1,642,518 1,443,022 
Less: Accumulated depreciation and depletion(272,701)(191,526)
Property, plant and equipment, net$1,369,817 $1,251,496 
The Company’s depreciation and depletion expense, net of amounts capitalized into inventories, was as follows:
For the year ended December 31,
(in thousands)202520242023
Depreciation expense
$69,587 $63,558 $43,998 
Depletion expense
$6,724 $13,036 $11,067 
v3.25.4
INTANGIBLE ASSETS (Tables)
 12 Months Ended
Dec. 31, 2025
Goodwill and Intangible Assets Disclosure [Abstract]  
Schedule of Finite-Lived Intangible Assets
The Company’s intangible assets are included in “Other non-current assets” within the Company’s Consolidated Balance Sheets and consisted of the following:
December 31,
(in thousands)20252024
Intangible assets with definite lives:
Patent and intellectual property license$8,963 $8,963 
Less: Accumulated amortization(2,788)(1,593)
Intangible assets, net$6,175 $7,370 
Schedule of Future Amortization Expense
The following table presents the estimated amortization expense related to intangible assets as of December 31, 2025:
(in thousands)
Period:
2026$1,195 
20271,195 
20281,195 
20291,195 
20301,195 
Thereafter200 
Total$6,175 
v3.25.4
ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS (Tables)
 12 Months Ended
Dec. 31, 2025
Asset Retirement Obligation And Environmental Remediation Obligations [Abstract]  
Schedule of Change in Asset Retirement Obligation
The following is a summary of the Company’s ARO:
December 31,
(in thousands)20252024
Beginning balance$7,395 $5,702 
Obligations settled(184)(184)
Accretion expense580 429 
Obligations incurred— 159 
Revision in estimated cash flows— 1,289 
Ending balance$7,791 $7,395 
Schedule Of Environmental Remediation Costs
As of December 31, 2025, the total environmental costs were as follows (in thousands):
Year ending December 31,
2026$919 
2027942 
2028965 
2029989 
20301,014 
Thereafter35,504 
Total40,333 
Effect of discounting(21,019)
Total environmental obligations$19,314 
v3.25.4
DEBT OBLIGATIONS (Tables)
 12 Months Ended
Dec. 31, 2025
Debt Disclosure [Abstract]  
Schedule of debt obligations
The Company’s current and non-current portions of long-term debt were as follows:
December 31, 2025December 31, 2024
(in thousands)
Principal Amount
Unamortized Debt Discount and Issuance Costs
Carrying Amount
Principal AmountUnamortized Debt Issuance CostsCarrying Amount
Convertible Notes due 2026$67,499 $(88)$67,411 $67,699 $(440)$67,259 
Convertible Notes due 2030
862,793 (17,492)845,301 862,793 (21,323)841,470 
Samarium Project Loan150,000 (63,971)86,029 — — — 
Total long-term debt
$1,080,292 $(81,551)998,741 $930,492 $(21,763)908,729 
Less: Current portion
(67,411)— 
Total long-term debt, net of current portion
$931,330 $908,729 
The current and non-current portions of the equipment notes, which are included within the Consolidated Balance Sheets in “Other current liabilities” and “Other non-current liabilities,” respectively, were as follows:
December 31,
(in thousands)20252024
Equipment notes
Current$3,904 $2,098 
Non-current20,366 539 
$24,270 $2,637 
Schedule of interest expense
Interest expense, net, including interest costs related to the Convertible Notes, was as follows:
For the year ended December 31,
(in thousands)202520242023
Interest cost on Convertible Notes:
Coupon interest$26,053 $19,256 $1,725 
Amortization of debt issuance costs4,182 3,901 3,536 
Total Convertible Notes interest cost
30,235 23,157 5,261 
Samarium Project Loan interest cost
4,376 — — 
Other interest cost
3,046 244 319 
Interest capitalized to property, plant and equipment, net
(6,176)(391)(326)
Interest expense, net
$31,481 $23,010 $5,254 
Schedule of debt maturities
The following is a schedule of debt repayments as of December 31, 2025:
(in thousands)2026 Notes2030 Notes
Samarium Project Loan
Equipment Notes
Year ending December 31,
2026$67,499 $— $— $3,904 
2027— — — 4,294 
2028— — — 4,606 
2029— — — 4,782 
2030— 862,793 — 5,096 
Thereafter— — 150,000 1,588 
Total minimum payments$67,499 $862,793 $150,000 $24,270 
v3.25.4
OPERATING LEASES (Tables)
 12 Months Ended
Dec. 31, 2025
Leases [Abstract]  
Schedule of operating lease cost
Total operating lease cost included the following components:
Location on Consolidated Statements of Operations
For the year ended December 31,
(in thousands)202520242023
Operating lease cost
Primarily Selling, general and administrative
$3,039 $1,916 $1,328 
Short-term lease cost
Primarily Cost of sales (excluding depreciation, depletion and amortization) (including related party)
3,670 3,163 2,134 
$6,709 $5,079 $3,462 
Schedule of operating lease terms and discount rates
Information related to our operating lease terms and discount rates was as follows:
December 31,
20252024
Weighted-average remaining lease term
3.6 years5.7 years
Weighted-average discount rate
6.5 %6.9 %
Maturities of operating lease liability
As of December 31, 2025, the maturities of the Company’s operating lease liabilities were as follows:
(in thousands)
Period:
2026$3,863 
20273,851 
20282,758 
20291,436 
20301,227 
Total lease payments13,135 
Less: Imputed interest(1,490)
Total$11,645 
Supplemental disclosure related to operating leases
Supplemental disclosure for the Consolidated Balance Sheets related to the Company’s operating leases is as follows:
Location on Consolidated Balance Sheets
December 31,
(in thousands)20252024
Operating leases:
Right-of-use assets
Other non-current assets
$13,214 $8,680 
Operating lease liability, currentOther current liabilities$3,216 $1,066 
Operating lease liability, non-current
Other non-current liabilities
8,429 5,798 
Total operating lease liabilities$11,645 $6,864 
v3.25.4
INCOME TAXES (Tables)
 12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Schedule of Components of Income Tax Benefit (Expense)
Income tax benefit (expense) consisted of the following:
For the year ended December 31,
(in thousands)202520242023
Current:
Federal$1,874 $148 $(178)
State(367)— (135)
Total current1,507 148 (313)
Deferred:
Federal30,178 21,883 (11,334)
State215 5,892 2,879 
Total deferred30,393 27,775 (8,455)
Total income tax benefit (expense)$31,900 $27,923 $(8,768)
Schedule of Loss Before Income Taxes, By Tax Jurisdiction
Income (loss) before income taxes, by tax jurisdiction, was as follows:
For the year ended December 31,
(in thousands)202520242023
United States$(117,774)$(93,347)$33,075 
Schedule of Effective Income Tax Rate Reconciliation
Income taxes differed from the amounts computed by applying the U.S. federal income tax rate of 21% to pretax income as a result of the following:
For the year ended December 31,
202520242023
(in thousands, except tax rates)PercentAmountPercentAmountPercentAmount
Computed income tax benefit (expense) at the statutory rate
21.0 %$24,733 21.0 %$19,603 21.0 %$(6,946)
Changes resulting from:
State and local income taxes, net of federal (national) income tax effect:
State and local income taxes, net of federal benefits(1)
2.8 %3,302 1.8 %1,700 2.6 %(867)
California Competes Tax Credit, net of federal detriment0.9 %1,019 1.9 %1,778 (11.3)%3,753 
State valuation allowance, net of federal benefits
(3.9)%(4,562)(0.1)%(50)4.1 %(1,360)
State rate change, net of federal benefits
0.2 %223 1.5 %1,354 (2.7)%872 
Tax credits:
Section 48C Qualifying Advanced Energy Project Tax Credit1.6 %1,911 0.2 %148 — %— 
Nontaxable or nondeductible items:
Limitation on officers’ compensation
(3.2)%(3,735)(1.9)%(1,815)11.0 %(3,640)
Percentage depletion in excess of basis
3.2 %3,761 3.5 %3,284 — %— 
Nondeductible transaction costs
(1.4)%(1,639)— %— — %— 
Section 45X Advanced Manufacturing Production Credit
3.6 %4,266 3.8 %3,543 (0.1)%38 
Other nontaxable or nondeductible items
(0.3)%(400)— %— — %— 
Other reconciling items:
Return-to-provision adjustments
1.7 %1,952 (0.2)%(202)0.5 %(155)
Excess tax benefits (expense) on stock-based compensation
0.8 %927 (1.4)%(1,312)0.6 %(190)
Other, net0.1 %142 (0.2)%(108)0.8 %(273)
Total effective tax rate and income tax benefit (expense)
27.1 %$31,900 29.9 %$27,923 26.5 %$(8,768)
(1)State taxes in California made up the majority (greater than 50%) of the tax effect in this category.
Schedule of Deferred Tax Assets and Liabilities
The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows:
December 31,
(in thousands)20252024
Deferred tax assets:
Asset retirement and environmental obligations$6,585 $6,442 
Net operating losses89,408 70,593 
Inventories4,436 1,828 
Stock-based compensation7,979 5,958 
Lease liabilities
2,991 1,852 
Credits15,491 11,119 
Capped call options8,095 9,846 
Deferred investment tax credit liability
6,139 5,805 
Deferred revenue
8,226 — 
Other2,710 3,052 
Gross deferred tax assets152,060 116,495 
Less: Valuation allowance(6,318)(1,756)
Net deferred tax assets145,742 114,739 
Deferred tax liabilities:
Property, plant and equipment(101,101)(103,133)
ROU assets
(3,366)(2,335)
Mineral rights(89,025)(92,533)
Other(3,808)(2,047)
Total deferred tax liabilities(197,300)(200,048)
Non-current deferred tax liabilities, net$(51,558)$(85,309)
v3.25.4
SUPPLEMENTAL BALANCE SHEET INFORMATION (Tables)
 12 Months Ended
Dec. 31, 2025
Balance Sheet Related Disclosures [Abstract]  
Schedule of Other Receivables
The Company’s other receivables consisted of the following:
December 31,
(in thousands)20252024
PPA income receivable
$51,016 $— 
Government grant receivable
41,980 19,799 
Apple prepayment receivable
32,000 — 
DoW reimbursement receivable
2,328 — 
Other receivables
3,714 800 
Other receivables
$131,038 $20,599 
Schedule of Accrued Liabilities
The Company’s accrued liabilities consisted of the following:
December 31,
(in thousands)20252024
Accrued payroll and related
$21,896 $17,370 
Accrued construction costs
60,289 36,016 
Accrued taxes
2,105 4,039 
Other accrued liabilities
10,796 7,302 
Accrued liabilities$95,086 $64,727 
v3.25.4
REVENUE RECOGNITION (Tables)
 12 Months Ended
Dec. 31, 2025
Revenue from Contract with Customer [Abstract]  
Disaggregation of Revenue
The following table disaggregates the Company’s revenue from contracts with customers by segment and by type of good sold, which are transferred to customers at a point in time:
For the year ended December 31,
(in thousands)
202520242023
Revenue category by segment
Materials segment
Rare earth concentrate
$41,992 $144,363 $252,468 
NdPr oxide and metal115,131 57,762 695 
Other revenue
3,246 1,730 282 
Total Materials segment revenue160,369 203,855 253,445 
Magnetics segment
Magnetic precursor products
66,861 — — 
Intersegment eliminations(1)
(2,789)— — 
Total revenue
$224,441 $203,855 $253,445 
(1)Represents the elimination of intersegment revenues associated with NdPr oxide sales made by the Materials segment to the Magnetics segment.
Contract with Customer, Contract Asset, Contract Liability, and Receivable The following table summarizes the activity of the Company’s deferred revenue:
For the year ended December 31,
(in thousands)20252024
Beginning balance(1)
$100,000 $— 
Additions to deferred revenue125,051 100,000 
Revenue recognized during the period(2)
(66,861)— 
Ending balance(1)
$158,190 $100,000 
(1) Contract liabilities are included as current and non-current deferred revenue in the Company’s Consolidated Balance Sheets based on the Company’s expectation of when the performance obligations will be satisfied.
(2) All the revenue recognized during the year ended December 31, 2025, was included in the beginning deferred revenue balance.
v3.25.4
GOVERNMENT GRANTS (Tables)
 12 Months Ended
Dec. 31, 2025
Government Assistance [Abstract]  
Benefits Recognized Pertaining to Government Assistance
The benefits (reduction of expenses) recognized in the Company’s Consolidated Statements of Operations pertaining to the 45X Credit were recorded as follows:
For the year ended December 31,
(in thousands)202520242023
Cost of sales (excluding depreciation, depletion and amortization) (including related party)$15,046 $12,199 $42 
Selling, general and administrative$2,858 $2,757 $— 
Depreciation, depletion and amortization$2,408 $1,916 $141 
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION (Tables)
 12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Schedule of performance awards activity
The following table contains information on the Company’s performance awards:
Number of SharesWeighted-Average Grant Date Fair Value
Nonvested as of January 1, 2025240,475 $32.43 
Granted757,748 $62.20 
Vested(3,189)$27.23 
Forfeited— $— 
Nonvested as of December 31, 2025995,034 $55.11 
Schedule of Stock Awards activity
The following table contains information on the Company’s Stock Awards:
Number of SharesWeighted-Average Grant Date Fair Value
Nonvested as of January 1, 20251,518,929 $24.71 
Granted1,154,402 $30.19 
Vested(847,618)$28.63 
Forfeited(121,590)$21.61 
Nonvested as of December 31, 20251,704,123 $26.69 
Schedule of stock-based compensation cost
The Company’s stock-based compensation and related income tax benefit were recorded as follows:
For the year ended December 31,
(in thousands)202520242023
Cost of sales (excluding depreciation, depletion and amortization)(including related party)
$6,914 $3,311 $3,932 
Selling, general and administrative22,197 19,074 20,508 
Start-up costs
871 381 723 
Advanced projects and development181 417 73 
Total stock-based compensation expense$30,163 $23,183 $25,236 
Stock-based compensation capitalized to property, plant and equipment, net$4,628 $1,573 $1,868 
Income tax benefit for stock-based compensation arrangements
$6,595 $4,454 $— 
v3.25.4
FAIR VALUE MEASUREMENTS (Tables)
 12 Months Ended
Dec. 31, 2025
Fair Value Disclosures [Abstract]  
Fair Value Measurement Inputs and Valuation Techniques The following assumptions were used within the model:
Valuation Assumptions:
December 31, 2025
Expected volatility
79.6 %
Risk-free interest rate
3.7 %
Discount rate
7.7 %
Dividend yield
— %
Term to maturity
4.2 years
Stock price
$50.52
Fair Value Disclosure of Asset and Liability Not Measured at Fair Value The carrying amounts and estimated fair values by input level of the Company’s financial instruments were as follows:
December 31, 2025
(in thousands)
Carrying
Amount
Fair ValueLevel 1Level 2Level 3
Financial assets:
Cash and cash equivalents$1,166,011 $1,166,011 $1,166,011 $— $— 
Short-term investments$664,275 $664,275 $664,275 $— $— 
Restricted cash$1,348 $1,348 $1,348 $— $— 
Derivative instrument
$8,708 $8,708 $— $— $8,708 
Financial liabilities:
2026 Notes$67,411 $82,449 $82,449 $— $— 
2030 Notes$845,301 $2,172,782 $2,172,782 $— $— 
Samarium Project Loan
$86,029 $98,081 $— $98,081 $— 
Equipment notes$24,270 $25,339 $— $25,339 $— 
December 31, 2024
(in thousands)
Carrying
Amount
Fair ValueLevel 1Level 2Level 3
Financial assets:
Cash and cash equivalents$282,442 $282,442 $282,442 $— $— 
Short-term investments$568,426 $568,426 $568,426 $— $— 
Restricted cash$1,161 $1,161 $1,161 $— $— 
Financial liabilities:
2026 Notes$67,259 $63,528 $63,528 $— $— 
2030 Notes$841,470 $902,395 $902,395 $— $— 
Equipment notes$2,637 $2,596 $— $2,596 $— 
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis The carrying amounts and estimated fair values by input level of the Company’s financial instruments were as follows:
December 31, 2025
(in thousands)
Carrying
Amount
Fair ValueLevel 1Level 2Level 3
Financial assets:
Cash and cash equivalents$1,166,011 $1,166,011 $1,166,011 $— $— 
Short-term investments$664,275 $664,275 $664,275 $— $— 
Restricted cash$1,348 $1,348 $1,348 $— $— 
Derivative instrument
$8,708 $8,708 $— $— $8,708 
Financial liabilities:
2026 Notes$67,411 $82,449 $82,449 $— $— 
2030 Notes$845,301 $2,172,782 $2,172,782 $— $— 
Samarium Project Loan
$86,029 $98,081 $— $98,081 $— 
Equipment notes$24,270 $25,339 $— $25,339 $— 
December 31, 2024
(in thousands)
Carrying
Amount
Fair ValueLevel 1Level 2Level 3
Financial assets:
Cash and cash equivalents$282,442 $282,442 $282,442 $— $— 
Short-term investments$568,426 $568,426 $568,426 $— $— 
Restricted cash$1,161 $1,161 $1,161 $— $— 
Financial liabilities:
2026 Notes$67,259 $63,528 $63,528 $— $— 
2030 Notes$841,470 $902,395 $902,395 $— $— 
Equipment notes$2,637 $2,596 $— $2,596 $— 
Schedule of Derivative Assets at Fair Value
The following table summarizes the changes in fair value of the Company’s Level 3 assets measured on a recurring basis:
(in thousands)
Derivative Instrument
Balance as of January 1, 2025$— 
Included in earnings(1)
8,708 
Balance as of December 31, 2025
$8,708 
(1)The gain is included in “Other income, net” within the Company’s Consolidated Statements of Operations.
v3.25.4
EARNINGS PER SHARE (Tables)
 12 Months Ended
Dec. 31, 2025
Earnings Per Share [Abstract]  
Schedule of weighted average number of shares
The following table reconciles the weighted-average common shares outstanding used in the calculation of basic earnings or loss per common share to the weighted-average common shares outstanding used in the calculation of diluted earnings or loss per common share:
For the year ended December 31,
202520242023
Weighted-average shares outstanding, basic170,126,753 166,840,611 177,181,661 
Assumed conversion of 2026 Notes
— 3,042,029 — 
Assumed conversion of restricted stock— — 609,326 
Assumed conversion of RSUs— — 361,225 
Weighted-average shares outstanding, diluted170,126,753 169,882,640 178,152,212 
Schedule of potentially dilutive securities
The following table presents unweighted potentially dilutive shares that were not included in the computation of diluted earnings or loss per common share because to do so would have been antidilutive:
For the year ended December 31,
202520242023
2026 Notes
— — 15,584,409 
2030 Notes
39,683,215 39,683,215 — 
Series A Preferred Stock
13,320,013 — — 
Warrant
11,201,659 — — 
RSUs1,704,123 1,518,929 3,184 
PSUs552,589 — — 
Total66,461,599 41,202,144 15,587,593 
Schedule of basic and diluted earnings per share
The following table presents the calculation of basic and diluted earnings or loss per common share:
For the year ended December 31,
(in thousands, except share and per share data)202520242023
Calculation of basic earnings (loss) per common share:
Net income (loss) attributable to common stockholders
$(85,874)$(65,424)$24,307 
Weighted-average shares outstanding, basic170,126,753 166,840,611 177,181,661 
Basic earnings (loss) per common share$(0.50)$(0.39)$0.14 
Calculation of diluted earnings (loss) per common share:
Net income (loss) attributable to common stockholders
$(85,874)$(65,424)$24,307 
Interest expense, net of tax(1):
2026 Notes
— 743 — 
Gain on early extinguishment of debt(1)(2)
— (32,426)— 
Diluted income (loss) attributable to common stockholders$(85,874)$(97,107)$24,307 
Weighted-average shares outstanding, diluted170,126,753 169,882,640 178,152,212 
Diluted earnings (loss) per common share$(0.50)$(0.57)$0.14 
(1)The year ended December 31, 2024, was tax-effected at a rate of 29.9%.
(2)Pertains to the 2026 Notes, a portion of which were repurchased during the year ended December 31, 2024.
v3.25.4
RELATED PARTY TRANSACTIONS (Tables)
 12 Months Ended
Dec. 31, 2025
Related Party Transactions [Abstract]  
Schedule of related party revenue and cost of sales The Company’s related-party revenue and cost of sales were as follows:
For the year ended December 31,
(in thousands)202520242023
Revenue:
Rare earth concentrate$41,992 $143,586 $242,516 
NdPr oxide and metal$9,315 $14,452 $— 
Cost of sales (excluding depreciation, depletion and amortization)
$31,461 $109,549 $89,260 
v3.25.4
SEGMENT REPORTING (Tables)
 12 Months Ended
Dec. 31, 2025
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment
The following tables present the Company’s reportable segment information:
For the year ended December 31, 2025
(in thousands)MaterialsMagneticsTotal
Revenue from external customers
$157,580 $66,861 $224,441 
Intersegment revenues(1)
2,789 — 2,789 
160,369 66,861 227,230 
Elimination of intersegment revenues(1)
(2,789)
Total consolidated revenues$224,441 
Price protection agreement income
51,016 — 
Significant segment expenses:
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(2)
159,466 28,904 
Selling, general and administrative (excluding stock-based compensation expense)(3)
33,073 11,105 
Other segment items(4)
2,028 403 
Segment Adjusted EBITDA
$16,818 $26,449 43,267 
Reconciling items to consolidated loss before income taxes
Corporate expenses and other(5)
(31,912)
Elimination of intersegment Adjusted EBITDA(1)
64 
Depreciation, depletion and amortization(89,267)
Interest expense, net(31,481)
Stock-based compensation expense(30,007)
Initial start-up costs
(3,339)
Transaction-related and other costs(6)
(35,965)
Accretion of asset retirement and environmental obligations(1,490)
Loss on environmental obligation
(259)
Loss on disposals of long-lived assets, net(466)
Other income, net63,081 
Loss before income taxes
$(117,774)
Segment capital expenditures$92,249 $79,772 $172,021 
Other capital expenditures(7)
354 
Total capital expenditures for the year ended December 31, 2025
$172,375 
(1)Relates to NdPr oxide sales made by the Materials segment to the Magnetics segment.
(2)The primary difference between this significant segment expense and “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Company’s Consolidated Statements of Operations relates to stock-based compensation, which as disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” was $6.9 million for the year ended December 31, 2025. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(3)The primary differences between this significant segment expense and “Selling, general and administrative” within the Company’s Consolidated Statements of Operations relates to stock-based compensation and unallocated corporate costs, which are included in Corporate expenses and other in the table above. As disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” the total stock-based compensation expense included in “Selling, general and administrative” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2025, was $22.2 million. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(4)Principally relates to expenses included in “Advanced projects and development” within the Company’s Consolidated Statements of Operations.
(5)Corporate expenses and other represents costs incurred at the corporate level that are not allocated to the operating segments, specifically relating to executive compensation, investor relations, other corporate costs, and unallocated shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. “Corporate expenses and other” is included in the table above to reconcile the total of Segment Adjusted EBITDA to the Company’s consolidated loss before income taxes.
(6)Pertains to legal, consulting, and advisory services, and other costs associated with specific matters or transactions, including $12.7 million of costs incurred in association with the DoW transactions, $11.9 million of costs associated with a construction-related litigation matter and $7.4 million of costs incurred to secure financing.
(7)Includes amounts not allocated to the reportable segments (primarily related to corporate).
For the year ended December 31, 2024
(in thousands)MaterialsMagneticsTotal
Revenue from external customers
$203,855 $— $203,855 
Total consolidated revenues$203,855 
Significant segment expenses:
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(1)
188,894 — 
Selling, general and administrative (excluding stock-based compensation expense)(2)
27,655 8,441 
Other segment items(3)
1,454 3,783 
Segment Adjusted EBITDA$(14,148)$(12,224)(26,372)
Reconciling items to consolidated loss before income taxes
Corporate expenses and other(4)
(23,796)
Depreciation, depletion and amortization(78,057)
Interest expense, net(23,010)
Stock-based compensation expense(23,183)
Initial start-up costs(5,303)
Transaction-related and other costs(8,367)
Accretion of asset retirement and environmental obligations(929)
Loss on environmental obligation(1,998)
Loss on disposals of long-lived assets, net(1,421)
Gain on early extinguishment of debt52,911 
Other income, net46,178 
Loss before income taxes$(93,347)
Segment capital expenditures$106,677 $79,741 $186,418 
Total capital expenditures for the year ended December 31, 2024
$186,418 
(1)The primary difference between this significant segment expense and “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Company’s Consolidated Statements of Operations relates to stock-based compensation, which as disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” was $3.3 million for the year ended December 31, 2024. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(2)The primary differences between this significant segment expense and “Selling, general and administrative” within the Company’s Consolidated Statements of Operations relates to stock-based compensation and unallocated corporate costs, which are included in “Corporate expenses and other” in the table above. As disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” the total stock-based compensation expense included in “Selling, general and administrative” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2024, was $19.1 million. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(3)Principally relates to expenses included in “Advanced projects and development” within the Company’s Consolidated Statements of Operations.
(4)Corporate expenses and other represents costs incurred at the corporate level that are not allocated to the operating segments, specifically relating to executive compensation, investor relations, other corporate costs, and unallocated shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. “Corporate expenses and other” is included in the table above to reconcile the total of Segment Adjusted EBITDA to the Company’s consolidated loss before income taxes.
For the year ended December 31, 2023
(in thousands)MaterialsMagneticsTotal
Revenue from external customers
$253,445 $— $253,445 
Total consolidated revenues$253,445 
Significant segment expenses:
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(1)
88,656 — 
Selling, general and administrative (excluding stock-based compensation expense)(2)
32,164 3,925 
Other segment items(3)
2,233 2,597 
Segment Adjusted EBITDA$130,392 $(6,522)123,870 
Reconciling items to consolidated income before income taxes
Corporate expenses and other(4)
(21,368)
Depreciation, depletion and amortization(55,709)
Interest expense, net(5,254)
Stock-based compensation expense(25,236)
Initial start-up costs(20,607)
Transaction-related and other costs(11,435)
Accretion of asset retirement and environmental obligations(908)
Loss on disposals of long-lived assets, net(6,326)
Other income, net56,048 
Income before income taxes$33,075 
Segment capital expenditures$164,287 $95,463 $259,750 
Other capital expenditures(5)
2,147 
Total capital expenditures for the year ended December 31, 2023
$261,897 
(1)The primary difference between this significant segment expense and “Cost of sales (excluding depreciation, depletion and amortization) (including related party)” within the Company’s Consolidated Statements of Operations relates to stock-based compensation, which as disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” was $3.9 million for the year ended December 31, 2023. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(2)The primary differences between this significant segment expense and “Selling, general and administrative” within the Company’s Consolidated Statements of Operations relates to stock-based compensation and unallocated corporate costs, which are included in “Corporate expenses and other” in the table above. As disclosed in Note 18, “Stockholders’ Equity and Stock-Based Compensation,” the total stock-based compensation expense included in “Selling, general and administrative” within the Company’s Consolidated Statements of Operations for the year ended December 31, 2023, was $20.5 million. Other differences are the result of excluding certain other costs because they are non-recurring, non-cash or are not related to the segments’ underlying business performance.
(3)Principally relates to expenses included in “Advanced projects and development” within the Company’s Consolidated Statements of Operations.
(4)Corporate expenses and other represents costs incurred at the corporate level that are not allocated to the operating segments, specifically relating to executive compensation, investor relations, other corporate costs, and unallocated shared service functions such as legal, information technology, human resources, finance and accounting and supply chain. “Corporate expenses and other” is included in the table above to reconcile the total of Segment Adjusted EBITDA to the Company’s consolidated income before income taxes.
(5)Includes amounts not allocated to the reportable segments (primarily related to corporate).
v3.25.4
SUPPLEMENTAL CASH FLOW INFORMATION (Tables)
 12 Months Ended
Dec. 31, 2025
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]  
Schedule of Cash Flow, Supplemental Disclosures SUPPLEMENTAL CASH FLOW INFORMATION
Supplemental cash flow information and non-cash investing and financing activities were as follows:
For the year ended December 31,
(in thousands)202520242023
Supplemental cash flow information:
Cash paid for interest, net of amounts capitalized
$23,097 $12,127 $2,059 
Cash payments (refunds) related to income taxes, net - federal(1)
$(23,460)$— $22,170 
Cash payments (refunds) related to income taxes, net - state$138 $870 $(2,065)
Change in construction payables and accrued construction costs$34,060 $(16,692)$18,086 
Supplemental non-cash investing and financing activities:
Property, plant and equipment acquired with equipment notes$27,029 $— $— 
Operating right-of-use assets obtained in exchange for lease liabilities$6,917 $36 $7,690 
Issuance of Series A Preferred Stock in exchange for PPA Upfront Asset$118,998 $— $— 
Issuance of Warrant in exchange for PPA Upfront Asset$75,142 $— $— 
Issuance of Samarium Project Loan in exchange for PPA Upfront Asset$24,460 $— $— 
Excise tax obligation related to repurchases of common stock$— $1,979 $— 
Increase in estimates of asset retirement costs
$— $1,289 $— 
2026 Notes retired in Debt Exchange$— $142,301 $— 
2030 Notes issued in Debt Exchange$— $115,293 $— 
Common stock issued in exchange for financial advisory services$— $3,737 $— 
Common stock issued to acquire intangible asset$— $— $8,963 
(1)The year ended December 31, 2024, excludes the receipt of $19.4 million related to the 45X Credit claimed on the Company’s 2023 federal tax return, as the 45X Credit is not within the scope of ASC 740. See Note 17, “Government Grants,” for additional information.
v3.25.4
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2025
segment
Jul. 09, 2025
USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Number of reportable segments | segment 2  
United States Department of War    
Government Assistance [Line Items]    
Minimum EBITDA under DoW Offtake Agreement | $   $ 140
v3.25.4
SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Jul. 09, 2025
Concentration Risk [Line Items]        
Allowance for credit losses $ 0 $ 0    
Property, Plant and Equipment [Line Items]        
DerivativeAssetStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag true      
United States Department of War        
Property, Plant and Equipment [Line Items]        
Term of price protection agreement       10 years
Land improvements | Minimum        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 10 years      
Land improvements | Maximum        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 25 years      
Buildings and building improvements | Minimum        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 10 years      
Buildings and building improvements | Maximum        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 40 years      
Machinery and equipment | Minimum        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 3 years      
Machinery and equipment | Maximum        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 20 years      
Mineral rights        
Property, Plant and Equipment [Line Items]        
Property, plant and equipment, useful life 28 years      
Customer B | Product sales | Customer concentration risk        
Concentration Risk [Line Items]        
Concentration risk percentage 23.00% 78.00% 96.00%  
Customer A | Product sales | Customer concentration risk        
Concentration Risk [Line Items]        
Concentration risk percentage 30.00% 20.00%    
Customer C | Product sales | Customer concentration risk        
Concentration Risk [Line Items]        
Concentration risk percentage 31.00%      
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - Other Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Jul. 09, 2025
USD ($)
T
Government Assistance [Line Items]        
PPA Upfront Asset amortization expense $ 11.4 $ 0.0 $ 0.0  
PPA Upfront Asset, remaining amortization period 10 years      
United States Department of War        
Government Assistance [Line Items]        
Projected Annual Magnet Capacity Expansion | T       3,000
Capital Expenditures Commitments       $ 600.0
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - Price Protection Agreement (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Jul. 09, 2025
Government Assistance [Line Items]        
Price protection agreement income $ 51,016,000 $ 0 $ 0  
United States Department of War        
Government Assistance [Line Items]        
Term of price protection agreement       10 years
Price floor per kilogram under price protection agreement       $ 110
Percentage of difference between Benchmark Price and price floor to be paid       30.00%
Price protection agreement income $ 51,000,000.0      
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - Offtake Agreement (Details) - United States Department of War
$ in Millions
Jul. 09, 2025
USD ($)
Government Assistance [Line Items]  
Term of DoW Offtake Agreement 10 years
Minimum EBITDA under DoW Offtake Agreement $ 140
Annual adjustment of Minimum EBITDA under DoW Offtake Agreement 2.00%
Threshold EBITDA Quarterly Advance Percentage under DoW Offtake Agreement 25.00%
Initial excess EBITDA payment amount under DoW Offtake Agreement $ 30
Excess of initial Excess EBITDA payment (percent) 50.00%
Maximum reimbursement for certain costs under DoW Offtake Agreement $ 30
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - Financings (Details)
$ / shares in Units, $ in Millions
 12 Months Ended
Aug. 31, 2025
USD ($)
Jul. 10, 2025
$ / shares
shares
Dec. 31, 2025
USD ($)
$ / shares
shares
Jul. 09, 2025
USD ($)
$ / shares
Dec. 31, 2024
$ / shares
Government Assistance [Line Items]          
Redeemable preferred stock, par value (in USD per share) | $ / shares     $ 0.0001   $ 0.0001
Maximum amount provided under a commitment letter | $       $ 1,000.0  
Commitment and structuring fees | $     $ 7.4    
Samarium Project Loan | Notes Payable, Other Payables          
Government Assistance [Line Items]          
Amount borrowed | $ $ 150.0        
Debt term 12 years        
Series A Convertible Preferred Stock          
Government Assistance [Line Items]          
Issuance of Series A Preferred Stock (in shares) | shares     400,000    
Redeemable preferred stock, par value (in USD per share) | $ / shares     $ 0.0001    
United States Department of War          
Government Assistance [Line Items]          
Potential ownership percentage upon conversion and exercise of convertible preferred equity and warrant       0.15  
United States Department of War | Series A Convertible Preferred Stock          
Government Assistance [Line Items]          
Issuance of Series A Preferred Stock (in shares) | shares   400,000      
Redeemable preferred stock, shares issuable | shares   13,320,013      
Conversion price of convertible preferred stock (usd per share) | $ / shares   $ 30.03      
United States Department of War | DoW Warrant          
Government Assistance [Line Items]          
Warrant term       10 years  
Number of securities called by warrants (in shares) | shares   11,201,659      
Exercise price of warrants (usd per share) | $ / shares       $ 30.03  
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - Consideration (Details) - USD ($)
$ in Thousands
 12 Months Ended
Jul. 09, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Government Assistance [Line Items]        
Measured value of consideration received $ 768,600      
Allocated transaction costs (11,300)      
Recognized amount of consideration received 771,102      
Measured value of consideration given 768,600      
Recognized amount of consideration given 759,802      
Cash consideration 550,000      
Non-cash consideration 218,600      
Series A Convertible Preferred Stock        
Government Assistance [Line Items]        
Cash consideration received 400,000      
Allocated transaction costs (4,789)      
Measured value of consideration given 418,400      
Recognized amount of consideration given 413,611      
Cash consideration 299,402      
Non-cash consideration 118,998 $ 118,998 $ 0 $ 0
DoW Warrant        
Government Assistance [Line Items]        
Allocated transaction costs (3,024)      
Measured value of consideration given 264,200      
Recognized amount of consideration given 261,176      
Cash consideration 189,058      
Non-cash consideration 75,142 75,142 0 0
Samarium Project Loan        
Government Assistance [Line Items]        
Cash consideration received 150,000      
Allocated transaction costs (985)      
Measured value of consideration given 86,000      
Recognized amount of consideration given 85,015      
Cash consideration 61,540      
Non-cash consideration 24,460 $ 24,460 $ 0 $ 0
All Issued Instruments        
Government Assistance [Line Items]        
Allocated transaction costs (8,798)      
Cash        
Government Assistance [Line Items]        
Measured value of consideration received 550,000      
Allocated transaction costs 0      
Recognized amount of consideration received 550,000      
PPA Upfront Asset        
Government Assistance [Line Items]        
Measured value of consideration received 218,600      
Allocated transaction costs (2,502)      
Recognized amount of consideration received $ 221,102      
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - PPA Upfront Asset (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Government Assistance [Abstract]    
PPA Upfront Asset, gross $ 221,102 $ 0
PPA Upfront Asset, accumulated amortization (11,434) 0
PPA Upfront Asset, net $ 209,668 $ 0
v3.25.4
PUBLIC-PRIVATE PARTNERSHIP WITH U.S. DEPARTMENT OF WAR - Remaining Amortization Expenses (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Government Assistance [Abstract]    
2026 $ 43,539  
2027 41,142  
2028 38,246  
2029 32,898  
2030 21,498  
Thereafter 32,345  
Total $ 209,668 $ 0
v3.25.4
CASH, CASH EQUIVALENTS AND INVESTMENTS - Amortized Costs, Unrealized Gains and Losses, and Estimated Fair Value (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Total cash and equivalents    
Amortized Cost Basis $ 1,165,944 $ 282,417
Unrealized Gains 67 25
Unrealized Losses 0 0
Estimated Fair Value 1,166,011 282,442
Short-term investments:    
Amortized Cost Basis 663,904 568,208
Unrealized Gains 371 230
Unrealized Losses 0 (12)
Short-term investments 664,275 568,426
Amortized Cost Basis 1,829,848 850,625
Unrealized Gains 438 255
Unrealized Losses 0 (12)
Total cash, cash equivalents and short-term investments 1,830,286 850,868
U.S. agency securities    
Short-term investments:    
Amortized Cost Basis 0 2,240
Unrealized Gains 0 0
Unrealized Losses 0 0
Short-term investments 0 2,240
U.S. Treasury securities    
Short-term investments:    
Amortized Cost Basis 636,214 544,410
Unrealized Gains 367 222
Unrealized Losses 0 (12)
Short-term investments 636,581 544,620
Commercial paper    
Short-term investments:    
Amortized Cost Basis 21,767 16,661
Unrealized Gains 4 6
Unrealized Losses 0 0
Short-term investments 21,771 16,667
Certificates of deposit    
Short-term investments:    
Amortized Cost Basis 5,923 4,897
Unrealized Gains 0 2
Unrealized Losses 0 0
Short-term investments 5,923 4,899
Demand deposits    
Total cash and equivalents    
Amortized Cost Basis 16,536 1,889
Unrealized Gains 0 0
Unrealized Losses 0 0
Estimated Fair Value 16,536 1,889
Money market funds    
Total cash and equivalents    
Amortized Cost Basis 748,322 164,477
Unrealized Gains 0 0
Unrealized Losses 0 0
Estimated Fair Value 748,322 164,477
U.S. Treasury securities    
Total cash and equivalents    
Amortized Cost Basis 334,339 86,320
Unrealized Gains 59 17
Unrealized Losses 0 0
Estimated Fair Value 334,398 86,337
Commercial paper    
Total cash and equivalents    
Amortized Cost Basis 48,762 29,731
Unrealized Gains 7 8
Unrealized Losses 0 0
Estimated Fair Value 48,769 29,739
Certificates of deposit    
Total cash and equivalents    
Amortized Cost Basis 17,985 0
Unrealized Gains 1 0
Unrealized Losses 0 0
Estimated Fair Value 17,986 0
Total cash equivalents    
Total cash and equivalents    
Amortized Cost Basis 1,149,408 280,528
Unrealized Gains 67 25
Unrealized Losses 0 0
Estimated Fair Value $ 1,149,475 $ 280,553
v3.25.4
CASH, CASH EQUIVALENTS AND INVESTMENTS - Debt Securities, Income and Expense (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]      
Interest and investment income(1) $ 52,015 $ 47,114 $ 55,637
v3.25.4
CASH, CASH EQUIVALENTS AND INVESTMENTS - Schedule of Investments Classified by Contractual Maturity Date (Details)
$ in Millions
Dec. 31, 2025
USD ($)
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]  
Due within one year $ 1,065.4
v3.25.4
INVENTORIES - Schedule of Inventories (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Inventory Disclosure [Abstract]    
Raw materials and supplies, including spare parts $ 56,491 $ 48,400
Mined ore stockpiles 23,795 31,142
Work in process 51,652 14,447
Finished goods 39,622 13,916
Total current inventories 171,560 107,905
Add: Non-current portion 80,539 19,031
Total inventories 252,099 126,936
Non-current mined ore stockpiles 24,100 12,300
Non-current bastnaesite concentrate stockpiles 31,700 0
Non-current lanthanum stockpiles $ 10,500 $ 0
v3.25.4
INVENTORIES - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Inventory Disclosure [Abstract]      
Write-down of inventories $ 3,038 $ 21,527 $ 2,285
v3.25.4
PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant, and Equipment (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 1,642,518 $ 1,443,022
Less: Accumulated depreciation and depletion (272,701) (191,526)
Property, plant and equipment, net 1,369,817 1,251,496
Land and land improvements    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 43,422 42,789
Buildings and building improvements    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 101,564 96,961
Machinery and equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 756,202 662,333
Assets under construction    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 302,935 202,544
Mineral rights    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 438,395 $ 438,395
v3.25.4
PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Property, Plant and Equipment [Abstract]      
Capitalized expenditures $ 206,400,000 $ 169,700,000 $ 280,000,000.0
Demolition costs     5,500,000
Asset impairment charges $ 0 $ 0 $ 0
v3.25.4
PROPERTY, PLANT AND EQUIPENT - Depreciation and Depletion Expense (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Property, Plant and Equipment [Abstract]      
Depreciation expense $ 69,587 $ 63,558 $ 43,998
Depletion expense $ 6,724 $ 13,036 $ 11,067
v3.25.4
EQUITY METHOD INVESTMENT - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
May 31, 2025
Schedule of Equity Method Investments [Line Items]        
Carrying amount of equity method investment $ 0 $ 9,100    
Proceeds from return of investment in equity method investee 9,673 0 $ 0  
Realized gain on disposal of equity method investment 1,300      
Impairment charge $ 0 $ 0 $ 0  
VREX Holdco Pte. Ltd.        
Schedule of Equity Method Investments [Line Items]        
Equity interest percentage       49.00%
v3.25.4
INTANGIBLE ASSETS - Finite-Lived Intangible Assets (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Intangible assets with definite lives:    
Patent and intellectual property license $ 8,963 $ 8,963
Less: Accumulated amortization (2,788) (1,593)
Intangible assets, net $ 6,175 $ 7,370
v3.25.4
INTANGIBLE ASSETS - Narrative (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Aug. 31, 2023
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]        
Amortization expense   $ 1.2 $ 1.2 $ 0.4
Remaining weighted-average useful life of amortizing intangible assets   5 years 2 months 12 days    
Intangible asset impairment   $ 0.0 $ 0.0 $ 0.0
Licensing Agreements        
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]        
Common stock issued to acquire intangible assets (in shares) 152,504 43,573 43,573  
Licensing Agreements | Third vesting period        
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]        
Stock to be issued, purchase of assets (in shares) 43,573      
Licensing Agreements | Fourth vesting period        
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]        
Stock to be issued, purchase of assets (in shares) 152,506      
v3.25.4
INTANGIBLE ASSETS - Remaining Amortization Expenses (Details)
$ in Thousands
Dec. 31, 2025
USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]  
2026 $ 1,195
2027 1,195
2028 1,195
2029 1,195
2030 1,195
Thereafter 200
Patent and intellectual property license, net $ 6,175
v3.25.4
ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Unusual Risk or Uncertainty [Line Items]    
ARO, revision of estimate $ 0 $ 1,289
Asset retirement obligations, noncurrent 7,700 7,200
Estimated undiscounted cash flows to satisfy obligation $ 51,400 51,600
Remediation term 30 years  
Discount rate 4.84%  
Loss on environmental obligations $ 259 1,998
Environmental obligations, undiscounted cost $ 40,333 39,500
Environmental Loss Contingency, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other non-current liabilities  
Environmental obligations, noncurrent $ 18,400 18,100
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Other current liabilities, Other non-current liabilities  
Closure and reclamation obligations, financial assurances $ 46,200 $ 45,500
Minimum    
Unusual Risk or Uncertainty [Line Items]    
Asset retirement obligations, credit-adjusted risk free rate 6.50%  
Maximum    
Unusual Risk or Uncertainty [Line Items]    
Asset retirement obligations, credit-adjusted risk free rate 11.50%  
v3.25.4
ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS - Summary of Asset Retirement Obligation (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Beginning balance $ 7,791 $ 7,395 $ 5,702
Obligations settled (184) (184)  
Accretion expense 580 429  
Obligations incurred 0 159  
Revision in estimated cash flows 0 1,289  
Ending balance $ 7,791 $ 7,395  
v3.25.4
ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS - Schedule of Environmental Remediation Costs (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Asset Retirement Obligation And Environmental Remediation Obligations [Abstract]    
2026 $ 919  
2027 942  
2028 965  
2029 989  
2030 1,014  
Thereafter 35,504  
Total 40,333 $ 39,500
Effect of discounting (21,019)  
Total environmental obligations $ 19,314  
v3.25.4
DEBT OBLIGATIONS - Schedule of Long-term Debt (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Debt Instrument [Line Items]    
Principal Amount $ 1,080,292 $ 930,492
Unamortized Debt Discount and Issuance Costs (81,551) (21,763)
Carrying amount 998,741 908,729
Long-Term Debt, Current Maturities (67,411) 0
Long-term debt, net of current portion 931,330 908,729
Convertible Notes Due 2026 | Convertible debt    
Debt Instrument [Line Items]    
Principal Amount 67,499 67,699
Unamortized Debt Discount and Issuance Costs (88) (440)
Carrying amount 67,411 67,259
Convertible Notes due 2030 | Convertible debt    
Debt Instrument [Line Items]    
Principal Amount 862,793 862,793
Unamortized Debt Discount and Issuance Costs (17,492) (21,323)
Carrying amount 845,301 841,470
Samarium Project Loan | Notes Payable, Other Payables    
Debt Instrument [Line Items]    
Principal Amount 150,000 0
Unamortized Debt Discount and Issuance Costs (63,971) 0
Carrying amount $ 86,029 $ 0
v3.25.4
DEBT OBLIGATIONS - Revolving Credit Facility (Details)
$ in Millions
Aug. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Revolving Credit Facility    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity $ 275.0  
Long-Term Line of Credit   $ 0.0
Line of Credit Facility, Remaining Borrowing Capacity   235.0
Debt Instrument, Covenant Trigger Event, EBITDA, Minimum 400.0  
Debt Instrument, Unrestricted Cash and Cash Equivalents Balance, Minimum $ 500.0  
Debt Instrument, Total Leverage Ratio, Following Covenant Trigger Event, Maximum 4.00  
Debt Instrument, Total Leverage Ratio, Stepped Up, Following Covenant Trigger Event, Maximum 4.50  
Debt Instrument, Cash Interest Coverage Ratio, Following Covenant Trigger Event, Minimum 3.0  
Letter of Credit    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity $ 200.0  
Line of Credit Facility, Remaining Borrowing Capacity   $ 160.0
Fed Funds Effective Rate Overnight Index Swap Rate | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 0.50%  
Secured Overnight Financing Rate (SOFR) | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 1.00%  
Secured Overnight Financing Rate (SOFR) | Maximum | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 2.50%  
Secured Overnight Financing Rate (SOFR) | Minimum | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 1.75%  
Base Rate | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 1.00%  
Base Rate | Maximum | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 1.50%  
Base Rate | Minimum | Revolving Credit Facility    
Debt Instrument [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 0.75%  
v3.25.4
DEBT OBLIGATIONS - Convertible Notes (Details)
$ / shares in Units, shares in Millions
 1 Months Ended 12 Months Ended
Mar. 31, 2021
USD ($)
d
$ / shares
Mar. 26, 2021
Dec. 31, 2024
USD ($)
Mar. 31, 2024
USD ($)
d
$ / shares
shares
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Mar. 07, 2024
USD ($)
Debt Instrument [Line Items]                
Gain on early extinguishment of debt     $ 6,600,000 $ 46,300,000 $ 0 $ 52,911,000 $ 0  
Capped Call transactions, initial cap price | $ / shares       $ 31.06        
Deferred tax impact of Capped call options     9,846,000   8,095,000 9,846,000    
Substantial premium on convertible debt, net of tax           13,826,000    
Call Option                
Debt Instrument [Line Items]                
Payments For Capped Call Option related to Convertible Debt           65,300,000    
Deferred tax impact of Capped call options     15,900,000     15,900,000    
Call Option | Common Stock, par value of $0.0001 per share                
Debt Instrument [Line Items]                
Shares covered by Capped Call Options | shares       34.4        
Convertible debt                
Debt Instrument [Line Items]                
Deferred tax impact of Debt Exchange     4,000,000.0     4,000,000.0    
Accrued and unpaid interest pertaining to the Convertible Notes     8,700,000   8,700,000 8,700,000    
Convertible debt | Convertible Notes Due 2026                
Debt Instrument [Line Items]                
Amount borrowed $ 690,000,000.0              
Debt instrument, interest rate, stated percentage 0.25%              
Debt instrument, repurchased face amount       $ 80,000,000.0       $ 400,000,000.0
Debt instrument, repurchased amount       70,600,000       $ 358,000,000.0
Percentage of par value of debt repurchased       0.895        
Debt instrument, convertible, conversion price (in dollars per share) | $ / shares $ 44.28              
Debt instrument, convertible, conversion ratio   0.0225861            
Debt instrument, principal exchanged in Debt Exchange     142,300,000   $ 0 142,301,000 0  
Effective interest rate         0.51%      
Debt term         3 months 18 days      
Convertible debt | Convertible Notes Due 2026 | Debt Instrument, Redemption, Period One                
Debt Instrument [Line Items]                
Debt instrument, convertible, threshold trading days | d 20              
Threshold consecutive trading days | d 30              
Debt instrument, convertible, threshold percentage of stock price trigger 130.00%              
Number of business days in which debt can be converted 5 days              
Consecutive business days 5 days              
Convertible debt | Convertible Notes Due 2026 | Debt Instrument, Redemption, Period Two                
Debt Instrument [Line Items]                
Debt instrument, convertible, percentage of product of the last reported sale price of the company’s common stock and the conversion rate on each such trading day 98.00%              
Convertible debt | Convertible Notes due 2030                
Debt Instrument [Line Items]                
Amount borrowed       $ 747,500,000        
Debt instrument, interest rate, stated percentage       3.00%        
Debt instrument, convertible, conversion price (in dollars per share) | $ / shares       $ 21.74        
Debt instrument, convertible, conversion ratio       0.0459939        
Debt Instrument, Issued, Principal     115,300,000   $ 0 115,293,000 $ 0  
Debt issuance costs     $ 4,500,000     $ 4,500,000    
Effective interest rate         3.52%      
Debt term         4 years 2 months 12 days      
Convertible debt | Convertible Notes due 2030 | Debt Instrument, Redemption, Period One                
Debt Instrument [Line Items]                
Debt instrument, convertible, threshold trading days | d       20        
Threshold consecutive trading days | d       30        
Debt instrument, convertible, threshold percentage of stock price trigger       130.00%        
Number of business days in which debt can be converted       5 days        
Consecutive business days       10 days        
Debt instrument, convertible, percentage of product of the last reported sale price of the company’s common stock and the conversion rate on each such trading day       98.00%        
v3.25.4
DEBT OBLIGATIONS - Samarium Project Loan (Details) - Samarium Project Loan - Notes Payable, Other Payables - USD ($)
$ in Millions
Aug. 31, 2025
Dec. 31, 2025
Debt Instrument [Line Items]    
Amount borrowed $ 150.0  
Debt term 12 years  
Interest rate 5.38%  
Debt Instrument, Stated Interest Rate, Basis Spread on US Treasury 1.00%  
Debt Instrument, Unamortized Discount $ 64.0  
Effective interest rate   12.30%
v3.25.4
DEBT OBLIGATIONS - Equipment Notes (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Nonrevolving Credit Facility    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity $ 40,000 $ 25,000
Line of Credit Facility, Remaining Borrowing Capacity 15,700  
Equipment notes    
Equipment notes    
Current 3,904 2,098
Non-current 20,366 539
Total equipment notes $ 24,270 $ 2,637
Equipment notes | Minimum    
Debt Instrument [Line Items]    
Debt term 4 years  
Interest rate 6.70%  
Equipment notes | Maximum    
Debt Instrument [Line Items]    
Debt term 6 years  
Interest rate 7.40%  
v3.25.4
DEBT OBLIGATIONS - Interest Expense, Net (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Debt Instrument [Line Items]      
Other interest cost $ 3,046 $ 244 $ 319
Interest capitalized 6,176 391 326
Interest expense, net 31,481 23,010 5,254
Convertible debt      
Debt Instrument [Line Items]      
Coupon interest 26,053 19,256 1,725
Amortization of debt issuance costs 4,182 3,901 3,536
Interest cost 30,235 23,157 5,261
Notes Payable, Other Payables | Samarium Project Loan      
Debt Instrument [Line Items]      
Interest cost $ 4,376 $ 0 $ 0
v3.25.4
DEBT OBLIGATIONS - Debt Maturities (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Year ending December 31,    
Total minimum payments $ 1,080,292 $ 930,492
Convertible debt | Convertible Notes Due 2026    
Year ending December 31,    
2026 67,499  
2027 0  
2028 0  
2029 0  
2030 0  
Thereafter 0  
Total minimum payments 67,499 67,699
Convertible debt | Convertible Notes due 2030    
Year ending December 31,    
2026 0  
2027 0  
2028 0  
2029 0  
2030 862,793  
Thereafter 0  
Total minimum payments 862,793 862,793
Notes Payable, Other Payables | Samarium Project Loan    
Year ending December 31,    
2026 0  
2027 0  
2028 0  
2029 0  
2030 0  
Thereafter 150,000  
Total minimum payments 150,000 $ 0
Equipment notes    
Year ending December 31,    
2026 3,904  
2027 4,294  
2028 4,606  
2029 4,782  
2030 5,096  
Thereafter 1,588  
Total minimum payments $ 24,270  
v3.25.4
OPERATING LEASES - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Lessee, Lease, Description [Line Items]      
Operating lease, ROU asset impairment charges $ 0 $ 0 $ 0
Deferred revenue 83,889 $ 43,120  
United States Department of War      
Lessee, Lease, Description [Line Items]      
Deferred revenue 2,300    
United States Department of War      
Lessee, Lease, Description [Line Items]      
DoW Offtake Agreement, Uncapitalized Costs Asset $ 2,300    
Minimum      
Lessee, Lease, Description [Line Items]      
Initial term 1 month    
Renewal options term 1 year    
Maximum      
Lessee, Lease, Description [Line Items]      
Initial term 8 years    
Renewal options term 5 years    
v3.25.4
OPERATING LEASES - Lease Cost (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Leases [Abstract]      
Operating lease cost $ 3,039 $ 1,916 $ 1,328
Short-term lease cost 3,670 3,163 2,134
Lease cost $ 6,709 $ 5,079 $ 3,462
v3.25.4
OPERATING LEASES - Lease Terms and Discount Rates (Details)
Dec. 31, 2025
Dec. 31, 2024
Leases [Abstract]    
Weighted-average remaining lease term 3 years 7 months 6 days 5 years 8 months 12 days
Weighted-average discount rate 6.50% 6.90%
v3.25.4
OPERATING LEASES - Maturities of Lease Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]    
2026 $ 3,863  
2027 3,851  
2028 2,758  
2029 1,436  
2030 1,227  
Total lease payments 13,135  
Less: Imputed interest (1,490)  
Total $ 11,645 $ 6,864
v3.25.4
OPERATING LEASES - Supplemental Disclosure for the Consolidated Balance Sheets (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Operating leases    
Right-of-use assets $ 13,214 $ 8,680
Operating lease liability, current 3,216 1,066
Operating lease liability, non-current 8,429 5,798
Total operating lease liabilities $ 11,645 $ 6,864
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other current liabilities Other current liabilities
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Other Assets, Noncurrent Other Assets, Noncurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other non-current liabilities Other non-current liabilities
v3.25.4
INCOME TAXES - Schedule of Income Tax Benefit (Expense) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Current:      
Federal $ 1,874 $ 148 $ (178)
State (367) 0 (135)
Total current 1,507 148 (313)
Deferred:      
Federal 30,178 21,883 (11,334)
State 215 5,892 2,879
Total deferred 30,393 27,775 (8,455)
Income tax benefit (expense) $ 31,900 $ 27,923 $ (8,768)
v3.25.4
INCOME TAXES - Schedule of Income (Loss) Before Taxes (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]      
Income (loss) before income taxes, United States $ (117,774) $ (93,347) $ 33,075
v3.25.4
INCOME TAXES - Schedule of Income Tax Rate Reconciliation (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Computed income tax benefit (expense) at the statutory rate 21.00% 21.00% 21.00%
State and local income taxes, net of federal (national) income tax effect:      
State and local income taxes, net of federal benefits(1) 2.80% 1.80% 2.60%
California Competes Tax Credit, net of federal detriment 0.90% 1.90% (11.30%)
State valuation allowance, net of federal benefits (3.90%) (0.10%) 4.10%
State rate change, net of federal benefits 0.20% 1.50% (2.70%)
Tax credits:      
Section 48C Qualifying Advanced Energy Project Tax Credit (1.60%) (0.20%) 0.00%
Nontaxable or nondeductible items:      
Limitation on officers’ compensation (3.20%) (1.90%) 11.00%
Percentage depletion in excess of basis 3.20% 3.50% 0.00%
Nondeductible transaction costs (1.40%) 0.00% 0.00%
Section 45X Advanced Manufacturing Production Credit (3.60%) (3.80%) 0.10%
Other nontaxable or nondeductible items (0.30%) 0.00% 0.00%
Other reconciling items:      
Return-to-provision adjustments 1.70% (0.20%) 0.50%
Excess tax benefits (expense) on stock-based compensation 0.80% (1.40%) 0.60%
Other, net 0.10% (0.20%) 0.80%
Total effective tax rate 27.10% 29.90% 26.50%
Effective Income Tax Rate Reconciliation, Amount [Abstract]      
Computed income tax benefit (expense) at the statutory rate $ 24,733 $ 19,603 $ (6,946)
State and local income taxes, net of federal (national) income tax effect:      
State and local income taxes, net of federal benefits(1) 3,302 1,700 (867)
California Competes Tax Credit, net of federal detriment 1,019 1,778 3,753
State valuation allowance, net of federal benefits (4,562) (50) (1,360)
State rate change, net of federal benefits (223) (1,354) (872)
Tax credits:      
Section 48C Qualifying Advanced Energy Project Tax Credit 1,911 148 0
Nontaxable or nondeductible items:      
Limitation on officers’ compensation (3,735) (1,815) (3,640)
Percentage depletion in excess of basis 3,761 3,284 0
Nondeductible transaction costs (1,639) 0 0
Section 45X Advanced Manufacturing Production Credit 4,266 3,543 38
Other nontaxable or nondeductible items (400) 0 0
Other reconciling items:      
Return-to-provision adjustments 1,952 (202) (155)
Excess tax benefits (expense) on stock-based compensation 927 (1,312) (190)
Other, net (142) 108 273
Income tax benefit (expense) $ 31,900 $ 27,923 $ (8,768)
v3.25.4
INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Deferred tax assets:    
Asset retirement and environmental obligations $ 6,585 $ 6,442
Net operating losses 89,408 70,593
Inventories 4,436 1,828
Stock-based compensation 7,979 5,958
Lease liabilities 2,991 1,852
Credits 15,491 11,119
Capped call options 8,095 9,846
Deferred investment tax credit liability 6,139 5,805
Deferred revenue 8,226 0
Other 2,710 3,052
Gross deferred tax assets 152,060 116,495
Less: Valuation allowance (6,318) (1,756)
Net deferred tax assets 145,742 114,739
Deferred tax liabilities:    
Property, plant and equipment (101,101) (103,133)
ROU assets (3,366) (2,335)
Mineral rights (89,025) (92,533)
Other (3,808) (2,047)
Total deferred tax liabilities (197,300) (200,048)
Non-current deferred tax liabilities, net $ (51,558) $ (85,309)
v3.25.4
INCOME TAXES - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Mar. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2021
Operating Loss Carryforwards [Line Items]          
Tax credit carryforward   $ 17,200      
California Competes tax credit   1,019 $ 1,778 $ 3,753  
Investment tax credit awarded $ 58,500        
Investment tax credit recognized   3,400 27,800    
Deferred investment tax credit, current   2,400 2,100    
Deferred investment tax credit, noncurrent   26,860 25,502    
Tax credit carryforward, subject to expiration in 2044   9,200      
Tax credit carryforward, not subject to expiration   2,200      
California Franchise Tax Board          
Operating Loss Carryforwards [Line Items]          
Tax credit carryforward         $ 14,800
California Competes tax credit   1,300 2,300 $ 4,800  
Tax credit carryforward, subject to expiration in 2029   5,800      
State and Local Jurisdiction          
Operating Loss Carryforwards [Line Items]          
Operating loss carryforwards   106,600 60,400    
Operating loss carryforwards, subject to expiration   105,600      
Operating loss carryforwards, carried forward indefinitely   1,000      
Federal Tax Authority          
Operating Loss Carryforwards [Line Items]          
Operating loss carryforwards   $ 390,700 $ 316,100    
v3.25.4
REDEEMABLE PREFERRED STOCK (Details)
$ / shares in Units, $ in Thousands
 12 Months Ended
Jul. 10, 2025
USD ($)
d
$ / shares
shares
Jul. 09, 2025
USD ($)
Dec. 31, 2025
USD ($)
shares
Dec. 31, 2024
USD ($)
shares
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Nov. 17, 2020
shares
Temporary Equity [Line Items]              
Preferred stock, authorized (shares) | shares     49,600,000 50,000,000     50,000,000
Redeemable preferred stock     $ 413,611 $ 0      
Series A Preferred Stock, Voting Rights     Voting Rights: The Series A Preferred Stock is nonvoting on all matters, other than those that would have a material adverse effect on the special rights, powers, preferences or privileges of the Series A Preferred Stock.        
Series A Preferred Stock, Convertible, Terms     Conversion: At the election of the DoW, the Series A Preferred Stock is convertible at any time into 13,320,013 shares of the Company’s common stock at an initial conversion price of $30.03, subject to customary anti-dilution adjustments.At the election of the Company, any time after the five-year anniversary of issuance, if the closing price per share of the Company’s common stock exceeds 150% of the then-current conversion price for at least 20 trading days in any period of 30 consecutive trading days, the Company may elect to convert all or any portion of the then-outstanding shares of Series A Preferred Stock into common stock at the then-current conversion price.        
Series A Preferred Stock, Redemption Terms     Redemption: Redemption is contingent upon certain insolvency events, including a deemed liquidation event, or upon certain reorganization events (e.g., share exchange, recapitalization, consolidation, or merger). The Series A Preferred Stock is classified as redeemable preferred stock (i.e., temporary equity) within the Company’s Consolidated Balance Sheets due to redemption rights for a deemed liquidation event that, in certain circumstances, is not solely within the Company’s control.        
Redeemable preferred stock, liquidation preference     $ 413,489 0      
Series A Convertible Preferred Stock              
Temporary Equity [Line Items]              
Cash consideration received   $ 400,000          
Series A Convertible Preferred Stock              
Temporary Equity [Line Items]              
Issuance of Series A Preferred Stock (in shares) | shares     400,000        
Issuance of Series A Preferred Stock, net of issuance costs     $ 413,611        
Redeemable preferred stock     413,611 0 $ 0 $ 0  
Series A Convertible Preferred Stock | United States Department of War              
Temporary Equity [Line Items]              
Issuance of Series A Preferred Stock (in shares) | shares 400,000            
Stated value of Series A Preferred Stock (per share) | $ / shares $ 1,000            
Issuance of Series A Preferred Stock, net of issuance costs $ 413,600            
Issuance of Series A Preferred Stock, allocated issuance costs $ 4,800            
Redeemable preferred stock     413,600        
Series A Preferred Stock, dividend rate percentage 7.00%            
Redeemable preferred stock, shares issuable | shares 13,320,013            
Conversion price of convertible preferred stock (usd per share) | $ / shares $ 30.03            
Redeemable Preferred Stock Conversion at the Election of the Company, Years after Issuance 5 years            
Redeemable Preferred Stock, Threshold Percentage of Stock Price Trigger 150.00%            
Redeemable Preferred Stock, Threshold Trading Days | d 20            
Redeemable Preferred Stock, Threshold Consecutive Trading Days | d 30            
Redeemable preferred stock, liquidation preference     $ 413,500 $ 0      
v3.25.4
SUPPLEMENTAL BALANCE SHEET INFORMATION - Other Receivables (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
PPA income receivable $ 51,016 $ 0
Government grant receivable 41,980 19,799
Other receivables 3,714 800
Other receivables 131,038 20,599
United States Department of War    
DoW reimbursement receivable 2,328 0
Apple    
Apple prepayment receivable $ 32,000 $ 0
v3.25.4
SUPPLEMENTAL BALANCE SHEET INFORMATION - Accrued Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Payables and Accruals [Abstract]    
Accrued payroll and related $ 21,896 $ 17,370
Accrued construction costs 60,289 36,016
Accrued taxes 2,105 4,039
Other accrued liabilities 10,796 7,302
Accrued liabilities $ 95,086 $ 64,727
v3.25.4
REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disaggregation of Revenue [Line Items]      
Revenue (including related party) $ 224,441 $ 203,855 $ 253,445
Operating Segments      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) 227,230 203,855 253,445
Operating Segments | Materials Segment      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) 160,369 203,855 253,445
Operating Segments | Magnetics Segment      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) 66,861 0 0
Intersegment Eliminations      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) (2,789) 0 0
Rare earth concentrate | Operating Segments | Materials Segment      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) 41,992 144,363 252,468
NdPr oxide and metal | Operating Segments | Materials Segment      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) 115,131 57,762 695
Other revenue | Operating Segments | Materials Segment      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) 3,246 1,730 282
Magnetic precursor products | Operating Segments | Magnetics Segment      
Disaggregation of Revenue [Line Items]      
Revenue (including related party) $ 66,861 $ 0 $ 0
v3.25.4
REVENUE RECOGNITION - Contract Balances (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Revenue from Contract with Customer [Abstract]      
Deferred revenue $ 158,190 $ 100,000 $ 0
Additions to deferred revenue 125,051 100,000  
Revenue recognized during the period $ (66,861) $ 0  
v3.25.4
REVENUE RECOGNITION - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Jul. 14, 2025
Dec. 31, 2025
Sep. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disaggregation of Revenue [Line Items]            
Revenue from external customers       $ 224,441 $ 203,855 $ 253,445
Additions to deferred revenue       125,051 100,000  
Current deferred revenue   $ 74,301   74,301 56,880  
Deferred revenue   158,190   158,190 100,000 0
Non-current deferred revenue   83,889   83,889 43,120  
General Motors Company            
Disaggregation of Revenue [Line Items]            
Additions to deferred revenue       50,000 100,000  
Current deferred revenue   74,300   74,300    
Deferred revenue   83,100   83,100    
Non-current deferred revenue   8,800   8,800    
Apple            
Disaggregation of Revenue [Line Items]            
Additions to deferred revenue   32,000 $ 40,000      
Non-current deferred revenue   $ 72,000   72,000    
Future prepayments under long-term supply agreement $ 200,000          
Revenue Under Bill-and-Hold Arrangement            
Disaggregation of Revenue [Line Items]            
Revenue from external customers       $ 66,900 $ 0 $ 0
v3.25.4
GOVERNMENT GRANTS - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Feb. 28, 2022
Government Assistance [Line Items]        
Proceeds from government awards used for construction $ 24,200 $ 96 $ 2,800  
Government grant receivable, current 41,980 19,799    
HREE production project agreement        
Government Assistance [Line Items]        
Optimization contribution       $ 35,000
Proceeds from government awards used for construction 24,200 0 $ 2,800  
45X Credit government grant        
Government Assistance [Line Items]        
Government grant receivable, current 42,000 19,800    
Deferred government grant, current 2,400 2,000    
45X Credit government grant | UNITED STATES        
Government Assistance [Line Items]        
Government grant receivable, current $ 19,800      
Receipt of 45X Credit   $ 19,400    
v3.25.4
GOVERNMENT GRANTS - Benefits Recognized (Details) - 45X Credit government grant - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Cost of sales (excluding depreciation, depletion and amortization)(including related party)      
Government Assistance [Line Items]      
Government Assistance, Operating Expense, Decrease (Increase) $ 15,046 $ 12,199 $ 42
Government Assistance, Operating Expense, Decrease (Increase), Statement of Income or Comprehensive Income [Extensible Enumeration] Cost of sales (excluding depreciation, depletion and amortization) (including related party) Cost of sales (excluding depreciation, depletion and amortization) (including related party) Cost of sales (excluding depreciation, depletion and amortization) (including related party)
Selling, general and administrative      
Government Assistance [Line Items]      
Government Assistance, Operating Expense, Decrease (Increase) $ 2,858 $ 2,757 $ 0
Government Assistance, Operating Expense, Decrease (Increase), Statement of Income or Comprehensive Income [Extensible Enumeration] Selling, general and administrative Selling, general and administrative Selling, general and administrative
Depreciation, Depletion and Amortization      
Government Assistance [Line Items]      
Government Assistance, Operating Expense, Decrease (Increase) $ 2,408 $ 1,916 $ 141
Government Assistance, Operating Expense, Decrease (Increase), Statement of Income or Comprehensive Income [Extensible Enumeration] Depreciation, depletion and amortization Depreciation, depletion and amortization Depreciation, depletion and amortization
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Common Stock and Preferred Stock (Details) - $ / shares
Dec. 31, 2025
Jul. 10, 2025
Dec. 31, 2024
Nov. 17, 2020
Capital Unit [Line Items]        
Capital stock, authorized (shares)       500,000,000
Common stock, authorized (shares) 450,000,000   450,000,000 450,000,000
Preferred stock, authorized (shares) 49,600,000   50,000,000 50,000,000
Common stock, par value (usd per share) $ 0.0001   $ 0.0001 $ 0.0001
Preferred stock, par value (usd per share) $ 0.0001   $ 0.0001 $ 0.0001
Series A Preferred Stock, authorized (shares)   400,000    
United States Department of War | Series A Convertible Preferred Stock        
Capital Unit [Line Items]        
Stated value of Series A Preferred Stock (per share)   $ 1,000    
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Public Offering of Common Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
Jul. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Nov. 17, 2020
Class of Stock [Line Items]          
Common stock, par value (usd per share)   $ 0.0001 $ 0.0001   $ 0.0001
Proceeds from issuance of common stock   $ 747,500 $ 0 $ 0  
Underwritten Public Offering          
Class of Stock [Line Items]          
Common stock issued (shares) 13,590,908        
Common stock, par value (usd per share) $ 0.0001        
Shares Issued, Price Per Share 55.00        
Shares Issued, Price Per Share, Underwriters Price $ 53.35        
Proceeds from issuance of common stock $ 724,200        
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Warrant (Details) - USD ($)
$ / shares in Units, $ in Thousands
Jul. 09, 2025
Jul. 10, 2025
Class of Warrant or Right [Line Items]    
Recognized amount of consideration given $ 759,802  
Allocated transaction costs 11,300  
DoW Warrant    
Class of Warrant or Right [Line Items]    
Recognized amount of consideration given 261,176  
Allocated transaction costs $ 3,024  
United States Department of War | DoW Warrant    
Class of Warrant or Right [Line Items]    
Warrant term 10 years  
Number of securities called by warrants (in shares)   11,201,659
Exercise price of warrants (usd per share) $ 30.03  
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Treasury Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Mar. 07, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Aug. 30, 2024
Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]            
Amount authorized under share repurchase program         $ 600,000 $ 300,000
Increase in amount authorized under share repurchase program         $ 300,000  
Repurchases of common stock (in shares) 12,300,000 0 15,200,000      
Repurchases of common stock $ 191,600 $ 0 $ 225,068 $ 0    
Average cost per share of shares acquired $ 15.53          
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Capped Call Options (Details) - USD ($)
$ in Thousands, shares in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2025
Mar. 31, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Capped call options $ 9,846 $ 8,095  
Call Option      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Payments For Capped Call Option related to Convertible Debt 65,300    
Capped call options $ 15,900    
Call Option | Common Stock, par value of $0.0001 per share      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares covered by Capped Call Options     34.4
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Performance Awards (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Market Based Performance Stock Units | 2023 Performance Share Plan      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares granted (in shares)     62,709
Vesting period 3 years    
Requisite service period 3 years    
Market Based Performance Stock Units | 2023 Performance Share Plan | Minimum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 0.00%    
Market Based Performance Stock Units | 2023 Performance Share Plan | Maximum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 200.00%    
Market Based Performance Stock Units | 2024 Performance Share Plan      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares granted (in shares)   177,766  
Vesting period 3 years    
Requisite service period 3 years    
Market Based Performance Stock Units | 2024 Performance Share Plan | Minimum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 0.00%    
Market Based Performance Stock Units | 2024 Performance Share Plan | Maximum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 200.00%    
Performance-Based Performance Stock Units | 2025 March Performance Share Plan      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares granted (in shares) 235,533    
Vesting period 3 years    
Requisite service period 3 years    
Performance-Based Performance Stock Units | 2025 March Performance Share Plan | Minimum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 0.00%    
Performance-Based Performance Stock Units | 2025 March Performance Share Plan | Maximum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 200.00%    
Performance-Based Performance Stock Units | 2025 OCT Performance Share Plan      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares granted (in shares) 400,382    
Performance-Based Performance Stock Units | 2025 OCT Performance Share Plan | Three Years      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting period 3 years    
Requisite service period 3 years    
Performance-Based Performance Stock Units | 2025 OCT Performance Share Plan | Four Years      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting period 4 years    
Requisite service period 4 years    
Performance-Based Performance Stock Units | 2025 OCT Performance Share Plan | Five Years      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting period 5 years    
Requisite service period 5 years    
Performance-Based Performance Stock Units | 2025 OCT Performance Share Plan | Minimum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 0.00%    
Performance-Based Performance Stock Units | 2025 OCT Performance Share Plan | Maximum      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vesting percentage of the awards granted (as a percent) 100.00%    
Performance Shares      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares granted (in shares) 757,748    
Weighted average grant date fair value $ 62.20 $ 26.09 $ 50.40
Unamortized compensation cost not yet recognized $ 48.1    
Unamortized compensation costs not yet recognized, weighted-average recognition period 3 years 3 months 18 days    
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Schedule of Stock Awards Activity (Details) - $ / shares
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Performance Shares      
Number of Shares      
Beginning balance (in shares) 240,475    
Granted (in shares) 757,748    
Vested (in shares) (3,189)    
Forfeited (in shares) 0    
Ending balance (in shares) 995,034 240,475  
Weighted-Average Grant Date Fair Value      
Beginning balance (in USD per share) $ 32.43    
Granted (in USD per share) 62.20 $ 26.09 $ 50.40
Vested (in USD per share) 27.23    
Forfeited (in USD per share) 0    
Ending balance (in USD per share) $ 55.11 $ 32.43  
Stock Awards      
Number of Shares      
Beginning balance (in shares) 1,518,929    
Granted (in shares) 1,154,402    
Vested (in shares) (847,618)    
Forfeited (in shares) (121,590)    
Ending balance (in shares) 1,704,123 1,518,929  
Weighted-Average Grant Date Fair Value      
Beginning balance (in USD per share) $ 24.71    
Granted (in USD per share) 30.19 $ 16.27 $ 24.13
Vested (in USD per share) 28.63    
Forfeited (in USD per share) 21.61    
Ending balance (in USD per share) $ 26.69 $ 24.71  
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Schedule of Stock-Based Compensation and Related Income Tax Benefit (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Total stock-based compensation expense $ 30,163 $ 23,183 $ 25,236
Stock-based compensation capitalized to property, plant and equipment, net 4,628 1,573 1,868
Income tax benefit for stock-based compensation arrangements 6,595 4,454 0
Cost of sales (excluding depreciation, depletion and amortization)(including related party)      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Total stock-based compensation expense 6,914 3,311 3,932
Selling, general and administrative      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Total stock-based compensation expense 22,197 19,074 20,508
Start-up costs      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Total stock-based compensation expense 871 381 723
Advanced projects and development      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Total stock-based compensation expense $ 181 $ 417 $ 73
v3.25.4
STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION - Other Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Nov. 17, 2020
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Nov. 30, 2020
RSUs          
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]          
Shares granted (in shares)   1,118,518 737,835 805,322  
Shares vested (in shares)   189,670 130,956 67,700  
Requisite service period   4 years      
RSUs | Non-employee directors          
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]          
Shares granted (in shares)   35,884 71,148 48,177  
Shares vested (in shares)   6,142 15,252 10,691  
Stock Awards          
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]          
Shares granted (in shares)   1,154,402      
Shares vested (in shares)   847,618      
Weighted average grant date fair value   $ 30.19 $ 16.27 $ 24.13  
Unamortized compensation cost not yet recognized   $ 23.3      
Unamortized compensation costs not yet recognized, weighted-average recognition period   2 years      
Shares vested, fair value   $ 29.3 $ 23.6 $ 20.7  
Performance Shares          
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]          
Shares granted (in shares)   757,748      
Shares vested (in shares)   3,189      
Weighted average grant date fair value   $ 62.20 $ 26.09 $ 50.40  
Unamortized compensation cost not yet recognized   $ 48.1      
Unamortized compensation costs not yet recognized, weighted-average recognition period   3 years 3 months 18 days      
2020 Incentive Plan          
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]          
Shares initially available for issuance (in shares)         9,653,671
Annual increase percentage in shares available for issuance 2.00%        
Shares available for future grants (in shares)   4,150,457      
v3.25.4
FAIR VALUE MEASUREMENTS - Valuation Assumptions (Details)
Dec. 31, 2025
$ / shares
yr
Expected volatility  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative Asset, Measurement Input 0.796
Risk-free interest rate  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative Asset, Measurement Input 0.037
Discount rate  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative Asset, Measurement Input 0.077
Dividend yield  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative Asset, Measurement Input 0
Term to maturity  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative Asset, Measurement Input | yr 4.2
Stock price  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative Asset, Measurement Input | $ / shares 50.52
v3.25.4
FAIR VALUE MEASUREMENTS - Carrying Values and Estimated Fair Values (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Financial assets:    
Cash and cash equivalents $ 1,166,011 $ 282,442
Level 1 | Fair Value, Recurring    
Financial assets:    
Cash and cash equivalents 1,166,011 282,442
Short-term investments 664,275 568,426
Restricted cash 1,348 1,161
Derivative instrument 0  
Level 1 | Fair Value, Nonrecurring | Convertible debt | Convertible Notes Due 2026    
Financial liabilities:    
Debt instruments 82,449 63,528
Level 1 | Fair Value, Nonrecurring | Convertible debt | Convertible Notes due 2030    
Financial liabilities:    
Debt instruments 2,172,782 902,395
Level 1 | Fair Value, Nonrecurring | Equipment notes    
Financial liabilities:    
Debt instruments 0 0
Level 1 | Fair Value, Nonrecurring | Notes Payable, Other Payables | Samarium Project Loan    
Financial liabilities:    
Debt instruments 0  
Level 2 | Fair Value, Recurring    
Financial assets:    
Cash and cash equivalents 0 0
Short-term investments 0 0
Restricted cash 0 0
Derivative instrument 0  
Level 2 | Fair Value, Nonrecurring | Convertible debt | Convertible Notes Due 2026    
Financial liabilities:    
Debt instruments 0 0
Level 2 | Fair Value, Nonrecurring | Convertible debt | Convertible Notes due 2030    
Financial liabilities:    
Debt instruments 0 0
Level 2 | Fair Value, Nonrecurring | Equipment notes    
Financial liabilities:    
Debt instruments 25,339 2,596
Level 2 | Fair Value, Nonrecurring | Notes Payable, Other Payables | Samarium Project Loan    
Financial liabilities:    
Debt instruments 98,081  
Level 3 | Fair Value, Recurring    
Financial assets:    
Cash and cash equivalents 0 0
Short-term investments 0 0
Restricted cash 0 0
Derivative instrument 8,708 0
Level 3 | Fair Value, Nonrecurring | Convertible debt | Convertible Notes Due 2026    
Financial liabilities:    
Debt instruments 0 0
Level 3 | Fair Value, Nonrecurring | Convertible debt | Convertible Notes due 2030    
Financial liabilities:    
Debt instruments 0 0
Level 3 | Fair Value, Nonrecurring | Equipment notes    
Financial liabilities:    
Debt instruments 0 0
Level 3 | Fair Value, Nonrecurring | Notes Payable, Other Payables | Samarium Project Loan    
Financial liabilities:    
Debt instruments 0  
Carrying Amount | Fair Value, Recurring    
Financial assets:    
Cash and cash equivalents 1,166,011 282,442
Short-term investments 664,275 568,426
Restricted cash 1,348 1,161
Derivative instrument 8,708  
Carrying Amount | Fair Value, Nonrecurring | Convertible debt | Convertible Notes Due 2026    
Financial liabilities:    
Debt instruments 67,411 67,259
Carrying Amount | Fair Value, Nonrecurring | Convertible debt | Convertible Notes due 2030    
Financial liabilities:    
Debt instruments 845,301 841,470
Carrying Amount | Fair Value, Nonrecurring | Equipment notes    
Financial liabilities:    
Debt instruments 24,270 2,637
Carrying Amount | Fair Value, Nonrecurring | Notes Payable, Other Payables | Samarium Project Loan    
Financial liabilities:    
Debt instruments 86,029  
Fair Value | Fair Value, Recurring    
Financial assets:    
Cash and cash equivalents 1,166,011 282,442
Short-term investments 664,275 568,426
Restricted cash 1,348 1,161
Derivative instrument 8,708  
Fair Value | Fair Value, Nonrecurring | Convertible debt | Convertible Notes Due 2026    
Financial liabilities:    
Debt instruments 82,449 63,528
Fair Value | Fair Value, Nonrecurring | Convertible debt | Convertible Notes due 2030    
Financial liabilities:    
Debt instruments 2,172,782 902,395
Fair Value | Fair Value, Nonrecurring | Equipment notes    
Financial liabilities:    
Debt instruments 25,339 $ 2,596
Fair Value | Fair Value, Nonrecurring | Notes Payable, Other Payables | Samarium Project Loan    
Financial liabilities:    
Debt instruments $ 98,081  
v3.25.4
FAIR VALUE MEASUREMENTS - Derivative Instrument (Details) - Level 3 - Fair Value, Recurring - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Derivative instrument $ 8,708 $ 0
Gain on derivative $ 8,708  
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other income, net  
v3.25.4
EARNINGS PER SHARE - Weighted Average Number of Shares Outstanding (Details) - shares
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Class of Warrant or Right [Line Items]      
Weighted-average shares outstanding, basic (in shares) 170,126,753 166,840,611 177,181,661
Weighted-average shares outstanding, diluted (in shares) 170,126,753 169,882,640 178,152,212
Convertible Notes Due 2026 | Convertible debt      
Class of Warrant or Right [Line Items]      
Assumed conversion of 2026 Notes (shares) 0 3,042,029 0
Restricted Stock [Member]      
Class of Warrant or Right [Line Items]      
Assumed conversion of stock awards (shares) 0 0 609,326
RSUs      
Class of Warrant or Right [Line Items]      
Assumed conversion of stock awards (shares) 0 0 361,225
v3.25.4
EARNINGS PER SHARE - Potentially Dilutive Securities (Details) - shares
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 66,461,599 41,202,144 15,587,593
Convertible Notes Due 2026 | Convertible Notes Due 2026      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 0 0 15,584,409
Convertible Notes due 2030 | Convertible Notes due 2030      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 39,683,215 39,683,215 0
Series A Convertible Preferred Stock      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 13,320,013 0 0
Warrant      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 11,201,659 0 0
RSUs      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 1,704,123 1,518,929 3,184
Performance Shares      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive shares not included in computation of diluted EPS 552,589 0 0
v3.25.4
EARNINGS PER SHARE - Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Calculation of basic EPS:      
Net income (loss) attributable to common stockholders $ (85,874) $ (65,424) $ 24,307
Weighted-average shares outstanding, basic (in shares) 170,126,753 166,840,611 177,181,661
Basic earnings (loss) per share (in USD per share) $ (0.50) $ (0.39) $ 0.14
Calculation of diluted EPS:      
Interest expense on convertible debt, net of tax $ 0 $ 743 $ 0
Gain on early extinguishment of debt, net of tax 0 (32,426) 0
Diluted income (loss) attributable to common stockholders $ (85,874) $ (97,107) $ 24,307
Weighted-average shares outstanding, diluted (in shares) 170,126,753 169,882,640 178,152,212
Diluted earnings (loss) per share (in USD per share) $ (0.50) $ (0.57) $ 0.14
Effective tax rate 27.10% 29.90% 26.50%
v3.25.4
EARNINGS PER SHARE - Narrative (Details)
Mar. 31, 2021
$ / shares
Convertible Notes Due 2026 | Convertible debt  
Debt Instrument [Line Items]  
Debt instrument, convertible, conversion price (in dollars per share) $ 44.28
v3.25.4
RELATED PARTY TRANSACTIONS - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Nov. 13, 2024
Jan. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]          
Purchases from related party     $ 19,700 $ 4,800 $ 8,300
Accounts receivable     14,642 18,645  
Related Party          
Related Party Transaction [Line Items]          
Accounts receivable     $ 0 $ 14,900  
2024 Offtake Agreement          
Related Party Transaction [Line Items]          
Initial term   2 years      
Extension period   1 year      
Aircraft Lease Agreement          
Related Party Transaction [Line Items]          
Aircraft lease annual rent $ 500        
v3.25.4
RELATED PARTY TRANSACTIONS - Related Party Revenue and Cost of Sales (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]      
Revenue (including related party) $ 224,441 $ 203,855 $ 253,445
Cost of sales (excluding depreciation, depletion and amortization) (including related party) 192,789 192,586 92,714
Related Party      
Related Party Transaction [Line Items]      
Cost of sales (excluding depreciation, depletion and amortization) (including related party) 31,461 109,549 89,260
Rare earth concentrate | Related Party      
Related Party Transaction [Line Items]      
Revenue (including related party) 41,992 143,586 242,516
NdPr oxide and metal | Related Party      
Related Party Transaction [Line Items]      
Revenue (including related party) $ 9,315 $ 14,452 $ 0
v3.25.4
SEGMENT REPORTING - Narrative (Details)
 12 Months Ended
Dec. 31, 2025
segment
Jul. 09, 2025
USD ($)
Segment Reporting Information [Line Items]    
Number of reportable segments | segment 2  
United States Department of War    
Segment Reporting Information [Line Items]    
Price floor per kilogram under price protection agreement | $   $ 110
v3.25.4
SEGMENT REPORTING - Reconciliation of Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers $ 224,441 $ 203,855 $ 253,445
Operating Segments      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 227,230 203,855 253,445
Operating Segments | External Customers      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 224,441    
Operating Segments | Intersegment Customers      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 2,789    
Operating Segments | Materials Segment      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 160,369 203,855 253,445
Operating Segments | Materials Segment | External Customers      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 157,580    
Operating Segments | Materials Segment | Intersegment Customers      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 2,789    
Operating Segments | Magnetics Segment      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 66,861 0 0
Operating Segments | Magnetics Segment | External Customers      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 66,861    
Operating Segments | Magnetics Segment | Intersegment Customers      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers 0    
Intersegment Eliminations      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Revenue from external customers $ (2,789) $ 0 $ 0
v3.25.4
SEGMENT REPORTING - Reconciliation of Adjusted EBITDA (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting, Reconciling Item for Primary Segment Measure of Profit or Loss from Segment to Consolidated [Line Items]      
Price protection agreement income $ 51,016 $ 0 $ 0
Commitment and structuring fees 7,400    
Operating Segments      
Segment Reporting, Reconciling Item for Primary Segment Measure of Profit or Loss from Segment to Consolidated [Line Items]      
Segment Adjusted EBITDA 43,267 (26,372) 123,870
Operating Segments | Materials Segment      
Segment Reporting, Reconciling Item for Primary Segment Measure of Profit or Loss from Segment to Consolidated [Line Items]      
Price protection agreement income 51,016    
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(1) 159,466 188,894 88,656
Selling, general and administrative (excluding stock-based compensation expense)(2) 33,073 27,655 32,164
Other segment items(4) 2,028 1,454 2,233
Segment Adjusted EBITDA 16,818 (14,148) 130,392
Operating Segments | Magnetics Segment      
Segment Reporting, Reconciling Item for Primary Segment Measure of Profit or Loss from Segment to Consolidated [Line Items]      
Price protection agreement income 0    
Cost of sales (excluding depreciation, depletion and amortization and stock-based compensation expense)(1) 28,904 0 0
Selling, general and administrative (excluding stock-based compensation expense)(2) 11,105 8,441 3,925
Other segment items(4) 403 3,783 2,597
Segment Adjusted EBITDA 26,449 $ (12,224) $ (6,522)
Intersegment Eliminations      
Segment Reporting, Reconciling Item for Primary Segment Measure of Profit or Loss from Segment to Consolidated [Line Items]      
Segment Adjusted EBITDA $ (64)    
v3.25.4
SEGMENT REPORTING - Segment Reporting Information (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Dec. 31, 2024
Mar. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]          
Depreciation, depletion and amortization     $ (89,267) $ (78,057) $ (55,709)
Interest expense, net     (31,481) (23,010) (5,254)
Share-based compensation expense, employee     (30,007) (23,183) (25,236)
Initial start-up costs     (3,339) (5,303) (20,607)
Transaction-related and other costs(6)     (35,965) (8,367) (11,435)
Accretion of asset retirement and environmental obligations     (1,490) (929) (908)
Loss on environmental obligation     (259) (1,998)  
Loss on disposals of long-lived assets, net     (466) (1,421) (6,326)
Gain on early extinguishment of debt $ 6,600 $ 46,300 0 52,911 0
Other income, net     63,081 46,178 56,048
Loss before income taxes     (117,774) (93,347) 33,075
Additions to property, plant and equipment     172,375 186,418 261,897
Stock-based compensation expense     30,163 23,183 25,236
Costs incurred in association with the DoW transactions     12,700    
Costs associated with a construction-related litigation matter     11,900    
Commitment and structuring fees     7,400    
Cost of sales (excluding depreciation, depletion and amortization)(including related party)          
Segment Reporting Information [Line Items]          
Stock-based compensation expense     6,914 3,311 3,932
Selling, general and administrative          
Segment Reporting Information [Line Items]          
Stock-based compensation expense     22,197 19,074 20,508
Segment Reporting, Reconciling Item, Corporate Nonsegment          
Segment Reporting Information [Line Items]          
Corporate expenses and other(5)     (31,912) (23,796) (21,368)
Segment capital expenditures     354   2,147
Operating Segments          
Segment Reporting Information [Line Items]          
Elimination of intersegment Adjusted EBITDA     (43,267) 26,372 (123,870)
Segment capital expenditures     172,021 186,418 259,750
Operating Segments | Materials Segment          
Segment Reporting Information [Line Items]          
Elimination of intersegment Adjusted EBITDA     (16,818) 14,148 (130,392)
Segment capital expenditures     92,249 106,677 164,287
Operating Segments | Magnetics Segment          
Segment Reporting Information [Line Items]          
Elimination of intersegment Adjusted EBITDA     (26,449) 12,224 6,522
Segment capital expenditures     79,772 $ 79,741 $ 95,463
Intersegment Eliminations          
Segment Reporting Information [Line Items]          
Elimination of intersegment Adjusted EBITDA     $ 64    
v3.25.4
SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Jul. 09, 2025
Dec. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Supplemental cash flow information:          
Cash paid for interest, net of amounts capitalized     $ 23,097 $ 12,127 $ 2,059
Change in construction payables and accrued construction costs     34,060 (16,692) 18,086
Supplemental non-cash investing and financing activities:          
Property, plant and equipment acquired with equipment notes     27,029 0 0
Operating right-of-use assets obtained in exchange for lease liabilities     6,917 36 7,690
Issuance of Issued Instrument in exchange for PPA Upfront Asset $ 218,600        
Excise tax obligation related to repurchases of common stock     0 1,979 0
Increase in estimates of asset retirement costs     0 1,289 0
Stock Issued During Period, Value, Issued for Financial Services     0 3,737 0
Common stock issued to acquire intangible asset     0 0 8,963
Series A Convertible Preferred Stock          
Supplemental non-cash investing and financing activities:          
Issuance of Issued Instrument in exchange for PPA Upfront Asset 118,998   118,998 0 0
DoW Warrant          
Supplemental non-cash investing and financing activities:          
Issuance of Issued Instrument in exchange for PPA Upfront Asset 75,142   75,142 0 0
Samarium Project Loan          
Supplemental non-cash investing and financing activities:          
Issuance of Issued Instrument in exchange for PPA Upfront Asset $ 24,460   24,460 0 0
45X Credit government grant | UNITED STATES          
Supplemental non-cash investing and financing activities:          
Receipt of 45X Credit       19,400  
Federal Tax Authority          
Supplemental cash flow information:          
Cash payments (refunds) related to income taxes, net     (23,460) 0 22,170
State and Local Jurisdiction          
Supplemental cash flow information:          
Cash payments (refunds) related to income taxes, net     138 870 (2,065)
Convertible Notes Due 2026 | Convertible debt          
Supplemental non-cash investing and financing activities:          
2026 Notes retired in Debt Exchange   $ 142,300 0 142,301 0
Convertible Notes due 2030 | Convertible debt          
Supplemental non-cash investing and financing activities:          
2030 Notes issued in Debt Exchange   $ 115,300 $ 0 $ 115,293 $ 0