OKLO INC., 10-K filed on 3/17/2026
Annual Report
v3.26.1
Cover page - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2025
Mar. 13, 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 001-40583    
Registrant Name Oklo Inc.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 86-2292473    
Entity Address, Address Line One 3190 Coronado Dr.    
Entity Address, City or Town Santa Clara    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 95054    
City Area Code 650    
Local Phone Number 550-0127    
Title of 12(b) Security Class A common stock, par value $0.0001 per share    
Trading Symbol OKLO    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity Public Float     $ 7
Entity Common Stock, Shares Outstanding   173,568,788  
Documents Incorporated by Reference
Portions of the registrant’s definitive proxy statement for its 2026 Annual Meeting of Stockholders (the “Proxy Statement”), to be filed within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K, are incorporated by reference in Part III. Except with respect to information specifically incorporated by reference in this Annual Report, the Proxy Statement shall not be deemed to be filed as part hereof.
    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Amendment Flag false    
Central Index Key 0001849056    
v3.26.1
Audit Information
 12 Months Ended
Dec. 31, 2025
Auditor Information [Abstract]  
Auditor Firm ID 34
Auditor Name Deloitte & Touche LLP
Auditor Location San Jose, California
v3.26.1
Consolidated Balance Sheets - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Current assets:    
Cash and cash equivalents $ 788,445,000 $ 97,132,000
Marketable debt securities 439,526,000 130,682,000
Prepaid and other current assets 25,798,000 4,125,000
Total current assets 1,253,769,000 231,939,000
Marketable debt securities, net of current portion 184,568,000 47,473,000
Property, plant and equipment, net 42,312,000 1,202,000
Operating lease right-of-use assets 1,384,000 982,000
Indefinite-lived intangible assets 27,500,000 0
Goodwill 6,621,000 0
Other assets 12,303,000 140,000
Total assets 1,528,457,000 281,736,000
Current liabilities:    
Accounts payable 4,145,000 2,970,000
Accrued expenses and other 20,497,000 1,885,000
Operating lease liabilities 904,000 481,000
Total current liabilities 25,546,000 5,336,000
Operating lease liabilities, net of current portion 546,000 543,000
Right of first refusal liability 25,000,000 25,000,000
Deferred tax liabilities 1,155,000 0
Total liabilities 52,247,000 30,879,000
Commitments and contingencies
Stockholders' equity:    
Class A common stock, $0.0001 par value – 500,000,000 shares authorized; 160,514,103 and 137,706,596 shares issued and outstanding as of December 31, 2025 and 2024, respectively 16,000 14,000
Additional paid-in capital 1,715,787,000 383,739,000
Accumulated deficit (240,772,000) (135,109,000)
Accumulated other comprehensive income 1,179,000 2,213,000
Total stockholders’ equity 1,476,210,000 250,857,000
Total liabilities and stockholders’ equity $ 1,528,457,000 $ 281,736,000
v3.26.1
Consolidated Balance Sheets (Parenthetical) - $ / shares
Dec. 31, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Common stock, par value (in dollars per share) $ 0.0001 $ 0.0001
Common stock, authorized (in shares) 500,000,000 500,000,000
Common stock, issued (in shares) 160,514,103 137,706,596
Common stock, outstanding (in shares) 160,514,103 137,706,596
v3.26.1
Consolidated Statements of Operations - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Operating expenses    
Research and development $ 58,852 $ 26,711
General and administrative 80,442 26,090
Total operating expenses 139,294 52,801
Loss from operations (139,294) (52,801)
Other income (loss)    
Change in fair value of simple agreements for future equity 0 (27,864)
Interest and dividend income, net 29,102 7,732
Total other income (loss) 29,102 (20,132)
Loss before income taxes (110,192) (72,933)
Income tax benefit (expense) 4,529 (683)
Net loss $ (105,663) $ (73,616)
Net loss per share:    
Basic - Class A common stock (in dollars per share) $ (0.72) $ (0.74)
Diluted - Class A common stock (in dollars per share) $ (0.72) $ (0.74)
Weighted-average common shares outstanding - basic - Class A common stock (in shares) 146,351,775 98,910,013
Weighted-average common shares outstanding - diluted - Class A common stock (in shares) 146,351,775 98,910,013
v3.26.1
Consolidated Statements of Comprehensive Loss - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Statement of Comprehensive Income [Abstract]    
Net loss $ (105,663) $ (73,616)
Other comprehensive (loss) income:    
Unrealized (loss) gain on marketable debt securities (1,034) 2,213
Total comprehensive loss $ (106,697) $ (71,403)
v3.26.1
Consolidated Statements of Stockholders’ Equity - USD ($)
$ in Thousands
Total
Underwritten Public Offering
At The Market Offering
Common Stock
Common Stock
Underwritten Public Offering
Common Stock
At The Market Offering
Common Stock
Restricted Stock
Additional Paid-in Capital
Additional Paid-in Capital
Underwritten Public Offering
Additional Paid-in Capital
At The Market Offering
Accumulated Deficit
Accumulated Other Comprehensive Income
Beginning balance of the period (in shares) at Dec. 31, 2023       69,242,940                
Balance as of beginning of the period at Dec. 31, 2023 $ (34,361)     $ 7       $ 27,125     $ (61,493) $ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Exercised (in shares)       2,256,157                
Exercise of stock options 1,044             1,044        
Issuance of common stock in connection with the Business Combination, net of transaction costs (in shares)       43,099,811                
Issuance of common stock in connection with the Recapitalization, net of transaction costs (Note 3) 258,955     $ 4       258,951        
Issuance of common stock upon conversion of simple agreements for future equity immediately before the Business Combination (in shares)       8,407,894                
Issuance of common stock upon conversion of simple agreements for future equity immediately before the Recapitalization (Note 3) $ 84,138     $ 1       84,137        
Issuance of common stock (in shares) 2,256,157     14,699,794                
Issuance of common stock $ 1,044     $ 2       (2)        
Stock-based compensation 12,484             12,484        
Change in unrealized gain on marketable debt securities 2,213                     2,213
Net loss $ (73,616)                   (73,616)  
Ending balance of the period (in shares) at Dec. 31, 2024 137,706,596     137,706,596                
Balance as of end of the period at Dec. 31, 2024 $ 250,857     $ 14       383,739     (135,109) 2,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Exercised (in shares) 2,759,216     2,759,216                
Exercise of stock options $ 4,028             4,028        
Issuance of stock in connection with acquisition of business (in shares)       820,840     274,339          
Issuance of common stock in connection with acquisition of business $ 27,408             27,408        
Issuance of common stock (in shares) 2,759,216       7,666,667 10,781,891 571,741          
Issuance of common stock $ 4,028 $ 440,102 $ 820,364   $ 1 $ 1     $ 440,101 $ 820,363    
Common stock withheld for taxes (in shares) (67,187)     (67,187)                
Common stock withheld for taxes $ (1,647)             (1,647)        
Stock-based compensation 41,795             41,795        
Change in unrealized gain on marketable debt securities (1,034)                     (1,034)
Net loss $ (105,663)                   (105,663)  
Ending balance of the period (in shares) at Dec. 31, 2025 160,514,103     160,514,103                
Balance as of end of the period at Dec. 31, 2025 $ 1,476,210     $ 16       $ 1,715,787     $ (240,772) $ 1,179
v3.26.1
Consolidated Statements of Cash Flows - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Cash flows from operating activities:    
Net loss $ (105,663,000) $ (73,616,000)
Adjustments to reconcile net loss to net cash used in operating activities:    
Depreciation and amortization 522,000 268,000
Change in fair value of simple agreements for future equity 0 27,864,000
Interest income and accretion of discount on marketable debt securities, net (3,485,000) (520,000)
Stock-based compensation 41,795,000 12,484,000
Deferred income taxes (4,529,000) 0
Change in operating assets and liabilities, net of effect of acquisition:    
Prepaid and other current assets (21,574,000) (1,520,000)
Other assets (77,000) (115,000)
Accounts payable (1,532,000) (1,762,000)
Accrued expenses and other 12,345,000 (1,504,000)
Operating lease right-of-use assets and liabilities 24,000 31,000
Net cash used in operating activities (82,174,000) (38,390,000)
Cash flows from investing activities:    
Purchases of property, plant and equipment (33,205,000) (352,000)
Purchases of marketable debt securities (820,480,000) (291,620,000)
Proceeds from redemptions of marketable debt securities 376,992,000 116,198,000
Payment for acquisition of business, net of cash acquired (900,000) 0
Purchase of other investments (12,086,000) 0
Net cash used in investing activities (489,679,000) (175,774,000)
Cash flows from financing activities:    
Proceeds from recapitalization 0 276,210,000
Payment of taxes from common stock withheld (1,647,000) 0
Proceeds from exercise of stock options 4,028,000 1,044,000
Proceeds from right of first refusal liability 0 25,000,000
Proceeds from simple agreements for future equity 0 10,232,000
Payment of offering costs and deferred issuance costs (2,814,000) (11,058,000)
Proceeds from sale of common stock, net of offering costs 1,263,599,000 0
Net cash provided by financing activities 1,263,166,000 301,428,000
Net increase in cash and cash equivalents 691,313,000 87,264,000
Cash and cash equivalents - beginning of year 97,132,000 9,868,000
Cash and cash equivalents - end of year 788,445,000 97,132,000
Supplemental noncash investing and financing activities:    
Issuance of common stock in connection with acquisition of business 27,408,000 0
Assumed liabilities in connection with acquisition of business 287,000 0
Offering costs included in accounts payable 79,000 0
Offering costs included in accrued expense and other 240,000 0
Deferred issuance costs included in accounts payable 0 1,906,000
Reclassification of simple agreements for future equity in connection with the Recapitalization 0 84,138,000
Reclassification of deferred issuance costs in connection with Recapitalization 0 5,510,000
Property, Plant and Equipment    
Supplemental noncash investing and financing activities:    
Purchases of property, plant and equipment and computer software in accounts payable and accrued expense and other 8,387,000 0
Software    
Supplemental noncash investing and financing activities:    
Purchases of property, plant and equipment and computer software in accounts payable and accrued expense and other $ 0 $ 540,000
v3.26.1
Nature of Operations and Organization
 12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Nature of Operations and Organization Nature of Operations and Organization
Oklo Inc. (the "Company" or "Oklo"), a Delaware corporation, and its subsidiaries are developing advanced fission power plants to provide clean, reliable, and affordable energy at scale. Oklo Technologies, Inc., a Delaware corporation and wholly owned subsidiary of Oklo Inc., was incorporated on July 3, 2013. Prior to the Recapitalization (as defined below), Oklo Technologies, Inc. was formerly known as Oklo Inc. (referred to herein as “Legacy Oklo”).

The Company plans to commercialize its metal-fueled fast reactor technology with the Aurora powerhouse product line. The Aurora product line is designed to produce from 15 and up to 75 megawatts of electricity (“MWe”) on fresh, recycled, or down-blended nuclear fuel. Advanced fission technology built on a deep history of successful operation, first demonstrated by the Experimental Breeder Reactor-II (“EBR-II”), which sold and supplied power to the grid and showed effective used nuclear fuel recycling capabilities over 30 years of operation. The Company is also commercializing nuclear fuel recycling, fuel fabrication technology that can convert used nuclear fuel into usable fuel for its reactors, and the production of radioisotopes.

Business Combinations

On May 9, 2024, the Company consummated a business combination with AltC Acquisition Corp. (“AltC”), pursuant to an Agreement and Plan of Merger and Reorganization dated July 11, 2023 (as amended, modified, supplemented, or waived, the “Merger Agreement”), resulting in a reverse recapitalization (the “Recapitalization”). Legacy Oklo was treated as the accounting acquirer, and AltC was renamed Oklo Inc. The transaction had no impact on previously reported net loss, cash flows, or total assets. See Note 3—Business Combinations—Recapitalization for additional information.

On February 28, 2025, the Company acquired Atomic Alchemy Inc. ("Atomic Alchemy"), to combine its expertise in building and operating fast reactors and nuclear fuel recycling with Atomic Alchemy’s expertise in its radioisotope business to meet the increasing demands for radioisotopes in medical, energy, industry, defense, and artificial intelligence applications. See Note 3—Business Combinations—Atomic Alchemy for additional information.
Liquidity and Capital Resources
As of December 31, 2025, the Company’s cash, cash equivalents and marketable debt securities were $1,412,539. The Company continues to incur significant operating losses. For the year ended December 31, 2025, the Company had a net loss of $105,663, loss from operations of $139,294 and net cash used in operating activities of $82,174. As of December 31, 2025, the Company had an accumulated deficit of $240,772.

The Company expects to utilize its existing cash, cash equivalents, and marketable debt securities to fund construction of its powerhouses, fuel fabrication, and recycling facilities, as well as its radioisotopes business, business operations, and growth plans and believes that its existing cash, cash equivalents, and marketable debt securities will be sufficient to fund its operations for the one-year period following the issuance date of these consolidated financial statements.
v3.26.1
Summary of Significant Accounting Policies
 12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies Summary of Significant Accounting Policies
Basis of Presentation

The accompanying financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”).
Segment Information

The Company has viewed its financial information on an aggregate basis for the purposes of evaluating financial performance and allocating the Company’s resources. The Company’s principal business consists primarily of research and development and deployment activities for its planned or in-process powerhouses, nuclear fuel recycling and fuel fabrication facilities, and its radioisotope production facilities. Accordingly, the Company has determined that it conducts its business in one operating and one reportable segment. For more information about the Company’s single operating and reportable segment, See Note 14 —Segment Information.
Principles of Consolidation

The consolidated financial statements include the Company’s accounts and those of its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated.
Use of Estimates

Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, judgments, and assumptions that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Actual results could differ materially from these estimates. On an ongoing basis, the Company evaluates its estimates, including those related to the valuation of the operating lease liabilities and operating right-of-use assets, useful lives of property, plant and equipment, valuation allowance on deferred tax assets, and fair value of acquired intangible assets and goodwill. These estimates, judgments, and assumptions are based on current and expected economic conditions, historical data, and experience available at the date of the accompanying consolidated financial statements, and various other factors that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Risk and Uncertainties
The Company is subject to continuing risks and uncertainties amidst a range of supply chain, construction, and design complexities and in connection with the market dynamics around fuel costs and the current macroeconomic environment, including as a result of inflation, instability in the global banking system, trade policy (including tariffs, export controls, and sanctions), and geopolitical factors. At this point, the extent to which these effects may impact the Company’s future financial condition or results of operations is uncertain, and as of the date of issuance of these consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the update of any estimates or judgments or an adjustment of the carrying value of any assets or liabilities. These estimates may change as new events occur and additional information is obtained and will be recognized in the consolidated financial statements as soon as they become known.

Net Loss Per Common Share

The Company’s basic net loss per share of common stock is computed based on the average number of outstanding shares of common stock for the period, by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock and common share equivalents of potentially dilutive securities outstanding for the period. Potentially dilutive securities include common stock equivalents. Since the Company was in a loss position for the periods presented, basic net loss per share of common stock is the same as diluted net loss per share of common stock since the effects of potentially dilutive securities are antidilutive.

The outstanding potentially dilutive common stock equivalents as of December 31, 2025 and 2024 for: (1) options to purchase shares of common stock of 6,468,440 and 9,470,382, respectively, (2) unvested restricted stock of 640,125 and none, respectively, and (3) unvested restricted stock units of 2,423,478 and 1,252,166, respectively, have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect.

Cash and Cash Equivalents

Cash and cash equivalents include cash and highly liquid investments in money market funds with an original contractual maturity at the date of purchase of three months or less.

Marketable Debt Securities, Available-for-Sale

The Company’s investments in marketable debt securities have been classified and accounted for as available-for-sale. The Company classifies its marketable debt securities as either short-term or long-term based on each instrument’s underlying contractual maturity date. The cost of marketable debt securities is adjusted for accretion of discounts and amortization of premiums to maturity. Such accretion and amortization, as well as interest and dividends, are included in interest and dividend income. The cost of securities sold is determined using the specific identification method. Unrealized gains and
losses on marketable debt securities classified as available-for-sale are recognized in other comprehensive (loss) income on the consolidated statements of comprehensive loss.

Marketable debt securities are subject to a periodic impairment review. If the Company does not intend to sell and it is not more likely than not that it will be required to sell the security prior to recovery of its amortized cost basis, it will determine whether a decline in fair value below the amortized cost basis is due to credit-related factors. The credit loss is measured as the amount by which the debt security’s amortized cost basis exceeds the estimate of the present value of cash flows expected to be collected, up to the difference between the amortized cost basis and the fair value. Impairment is assessed at the individual security level. Credit-related impairment is recognized as an allowance in the consolidated balance sheets with a corresponding adjustment to investment income, net, in the consolidated statements of operations and comprehensive loss. Any impairment that is not credit-related is recognized in accumulated other comprehensive income in the consolidated balance sheets.

The Company does not separately measure an allowance for credit losses on accrued interest receivables on its marketable debt securities. Accrued interest receivable on available-for-sale marketable debt securities for U.S. Treasury securities are recorded in prepaid expenses and other current assets on the consolidated balance sheets. Interest receivables on available-for-sale marketable debt securities for U.S. Treasury securities (representing U.S. Treasury notes and U.S Treasury bills) and commercial paper are recorded directly within marketable debt securities on the consolidated balance sheets.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of cash, cash equivalents and marketable debt securities. The Company’s policy is to invest cash in institutional money market funds and marketable debt securities of the U.S. government to limit the amount of credit exposure. The Company currently maintains a portfolio of cash equivalents and marketable debt securities in money market funds and U.S. treasury securities. A portion of the Company’s operating cash is held in accounts in excess of the Federal Deposit Insurance Corporation insurance limits; however, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. The Company has not experienced any losses on cash equivalents and marketable debt securities.

Property, Plant and Equipment

Property, plant and equipment are stated at cost, net of accumulated depreciation and amortization. Expenditures for repairs and maintenance that do not improve or extend the life of the assets are expensed as incurred. When property, plant and equipment are sold or otherwise disposed of, the related cost and accumulated depreciation and amortization are removed from the respective accounts, and any resulting gains or losses are included on the consolidated statements of operations. Leasehold improvements are capitalized and amortized over the shorter of the lease term of the respective leases or estimated useful life of the asset, which includes reasonably certain renewal options.

Impairment of Long-Lived Assets

The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When such events or changes in circumstances occur, the Company assesses the recoverability of long-lived assets by determining whether the carrying value of such assets will be recovered through their undiscounted expected future cash flow. If the future undiscounted cash flow is less than the carrying amount of these assets, the Company recognizes an impairment loss based on the excess of the carrying amount over the fair value of the assets. No impairment losses were recognized on any long-lived assets during the years ended December 31, 2025 and 2024.

Indefinite-Lived Intangible Assets

Intangible assets with indefinite lives consist of in-process research and development ("IPR&D") from the Company’s acquisition of Atomic Alchemy. See Note 3—Business Combinations—Atomic Alchemy for additional information. These assets are tested annually for impairment in the fourth quarter each year, or whenever events or circumstances indicate that the carrying amount may not be recoverable, until completion or abandonment of research and development efforts associated with the projects. If potential impairment is identified, the process of evaluating the potential impairment of these assets involves significant judgment regarding estimates of the future cash flows associated with each asset. Upon
successful completion of each project, the IPR&D intangible asset is reclassified as a finite-lived intangible asset and amortized over the remaining useful life.

Goodwill

Goodwill represents the excess purchase consideration of an acquired business over the estimated fair value of the net assets acquired and is not amortized. Goodwill is evaluated for impairment annually in the fourth quarter each year, or whenever events or circumstances indicate that the carrying amount may not be recoverable. If the carrying amount of the Company’s reporting unit exceeds its fair value, an impairment loss is recognized for any excess of the carrying amount of the reportable segment’s goodwill over the implied fair value of the goodwill.

Other Investments

Investments in which the Company does not have the ability to exercise significant influence and does not have readily determinable fair values, are recorded at cost minus impairment, plus or minus changes from observable price changes in orderly transactions for identical or similar investments of the same issuer, in accordance with the measurement alternative described in Accounting Standards Codification (“ASC”) 321, Investments–Equity Securities. See Note 4—Balance Sheet Components for further information.

As part of the Company’s policy to maximize return on strategic investment opportunities, while preserving capital and limiting downside risk, the Company may at times enter into equity investments or simple agreements for future equity. The nature and timing of the Company’s investments will depend on available capital at any particular time and the investment opportunities identified and available to the Company. However, the Company generally does not make investments for speculative purposes and does not intend to engage in the business of making other investments.

Leases

The Company has lease arrangements for its offices and facilities. The Company determines if an arrangement is a lease at inception by evaluating whether the arrangement conveys the right-of-use (“ROU”) to an identified asset and whether the Company obtains substantially all of the economic benefits from and has the ability to direct the use of the asset. Leases are recorded as an operating lease right-of-use assets and operating lease liabilities on the consolidated balance sheets. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets.

Lease 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. Lease ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the expected lease term, including options to extend the lease when it is reasonably certain that the Company will exercise that option. The Company uses the discount rate implicit in the lease unless that rate cannot be readily determined. In that case, the Company uses its incremental borrowing rate, which is the rate of interest that the Company would have to pay to borrow on a collateralized basis an amount equal to the lease payments over the expected lease term. Lease ROU assets consist of the initial measurement of lease liabilities, any lease payments made to lessor on or before the lease commencement date, adjusted for any lease incentives received, and any initial direct costs incurred by the Company.

Operating lease expense for lease payments is recognized on a straight-line basis over the expected lease term. There were no finance leases as of December 31, 2025 and 2024.

Fair Value Measurements

The authoritative guidance with respect to fair value established a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels and requires that assets and liabilities carried at fair value be classified and disclosed in one of three categories, as presented below. There were no transfers in and out of Levels 1 and 2, and activity in Level 3 fair value measurements.

Financial instruments measured at fair value on a recurring basis were based upon a three-tier hierarchy as follows:

Level 1: Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities and investments in U.S. treasury securities and money market funds.
Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, as corroborated by market data.

Level 3: Unobservable inputs in which little or no market data exists, therefore developed using management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date.

The Company determines the level in the fair value hierarchy within which each fair value measurement falls in its entirety, based on the lowest level input that is significant to the fair value measurement in its entirety. In determining the appropriate levels, the Company performs an analysis of the assets and liabilities at each reporting period end.

The Company’s cash and cash equivalents, prepaid and other current assets, accounts payable, and accrued expenses and other approximate their fair value due to the short-term nature of these assets and liabilities. The Company’s marketable debt securities are classified as Level 1 or Level 2 assets. See Note 6—Financial Instruments for further information.

Research and Development

Research and development represent costs incurred to develop the Company’s technologies. These costs consist of personnel costs, including salaries, employee benefit costs, bonuses and stock-based compensation expenses, software costs, computing costs, hardware and experimental supplies and prototyping, and expenses for outside engineering contractors for analytical work and consulting costs, as well as depreciation and amortization expense for capitalized assets associated with these functions. The Company expenses all research and development costs in the periods in which they are incurred.

General and Administrative

General and administrative expenses consist primarily of payroll and other personnel-related costs, including stock-based compensation expense, for the Company’s employees involved in general corporate functions including finance, legal, procurement, and human resources, rent and other occupancy expenses, professional fees for legal and accounting, travel costs, promotional expenses, as well as depreciation and amortization expense for capitalized assets associated with these functions.

Cost-Share Projects

The Company has certain cost-share reimbursable projects for several research and development (“R&D”) projects related to nuclear recycling technologies awarded by the DOE’s Advanced Research Projects Agency-Energy (“ARPA-E”) (the “cost-share projects”) where the Company elected to record the reimbursements on a net presentation basis based on the period in which the expense was incurred and reimbursable under the guidelines of the cost-share projects on the consolidated statements of operations. Additionally, reimbursable R&D expenses for equipment purchased under the guidelines of the cost-share projects are offset to the cost basis of the equipment, resulting in no carrying value for the property, plant and equipment on the consolidated balance sheets and no reported cash flows. In the event the equipment is sold upon completion of the cost-share projects, the Company may be obligated to reimburse the DOE in the event the proceeds are in excess of $5 per asset, which at such time, if applicable, will be reported on a net presentation basis with no gain recognized and no cash flows.

Stock-Based Compensation

The Company accounts for stock-based compensation by measuring and recognizing expense for all stock-based awards made to employees and non-employees based on the estimated grant-date fair values for all stock-based compensation arrangements. The Company recognizes stock-based compensation over each recipient’s requisite service period, which is generally the vesting period. The Company has elected to recognize actual forfeitures by reducing the stock-based compensation in the same period as the forfeitures occur. The Company estimates the fair value of stock options granted to employees and non-employees using the Black-Scholes option pricing model. The Black-Scholes option pricing model requires the input of subjective assumptions, including the Legacy Oklo’s common stock fair value and the Company’s common stock fair value, expected volatility, expected dividend yield, risk-free rate of return, and the expected term. The Company classifies stock-based compensation costs in the same manner in which the award recipient’s cash compensation cost is classified on the consolidated statements of operations. See Note 10—Stock-based Compensation for further information.
Income Taxes

Because the Company has not generated revenue from the sale of power from its powerhouses or sales of radioisotopes and is anticipated to remain as such for the next several years, income taxes have been minimal to date. The Company follows the asset and liability method of accounting for income taxes under ASC 740, Income Taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that included the enactment date. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized.

ASC 740 prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. The Company is currently not aware of any issues under review that could result in significant payments, accruals, or material deviation from its position.

Recently Adopted Accounting Standards

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances the transparency and decision usefulness of income tax disclosures. The amendments, among other items, require (i) additional disaggregation of income taxes paid by jurisdiction, (ii) enhanced effective tax rate reconciliation disclosures with specified categories and further disaggregation when quantitative thresholds are met, and (iii) incremental disclosures about income taxes in certain circumstances. The Company is adopting ASU 2023-09 in its annual financial statements in the current year ended December 31, 2025. The Company is applying the amendments retrospectively to all periods presented upon adoption. The amendments primarily impact disclosures and do not have a material impact on the Company’s consolidated financial position, results of operations, or cash flows.

Recently Issued and Not Adopted Accounting Standards

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which will require disaggregated disclosures in the notes to the financial statements of certain categories of expenses, including purchases of inventory, employee compensation, and depreciation and amortization, that are included in expense line items within the statement of operations. ASU 2024-03 will be applied prospectively; however, retrospective application is permitted. ASU 2024-03, as clarified in ASU 2025-01, Clarifying the Effective Date, requires public business entities to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is evaluating the impact of ASU 2024-03 on its disclosures in the notes to its financial statements.

In September 2025, the FASB issued ASU 2025‑06, Intangibles—Goodwill and Other—Internal‑Use Software (Subtopic 350‑40): Targeted Improvements to the Accounting for Internal‑Use Software, which updates the guidance for capitalization of internal‑use software costs, including clarifications to the criteria for capitalizing configuration, development, and implementation activities. ASU 2025-06 is effective for the Company beginning with interim reporting for fiscal year 2029. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2025-06 on its accounting policies and related disclosures.

In December 2025, the FASB issued ASU 2025‑10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which provides updated guidance on how to recognize, measure, and present government grants. ASU 2025‑10 is effective for the Company for annual periods beginning after December 15, 2028, including interim periods within those periods using a modified prospective, modified retrospective, or full retrospective transition
approach. Early adoption is permitted. The Company is currently assessing the effect of ASU 2025-10 on its financial statements.

Management does not believe that any other recently issued, but not yet effective, authoritative guidance, if currently adopted, would have a material impact on the Company’s financial statement presentation or disclosures.

Reclassifications

Certain prior year amounts have been reclassified to conform to current period presentation. These reclassifications were immaterial, both individually and in aggregate. These changes did not impact previously reported loss from operations or net loss.
v3.26.1
Business Combination
 12 Months Ended
Dec. 31, 2025
Business Combination [Abstract]  
Business Combination Business Combinations
Atomic Alchemy

On February 28, 2025 (the “Acquisition Date”), the Company acquired Atomic Alchemy’s common stock in a business combination for its radioisotope business located in the U.S. The purchase price of $28,424 was comprised of (i) a cash portion of $900, net of cash acquired, paid at the Acquisition Date to certain Atomic Alchemy equity holders for their respective portion of the consideration, and (ii) the issuance of 820,840 shares of the Company’s common stock representing stock consideration in exchange of Atomic Alchemy’s common stock. At the Acquisition Date, the Company’s common stock public trading price of $33.39 per share was used to measure the stock consideration of $27,408.

In connection with the business combination, the Company issued 274,339 shares of its common stock, subject to certain lock-up provisions, vesting conditions, and substantial risk of forfeiture, representing postcombination services, pursuant to an employment agreement and vesting agreement.

The composition of the purchase price is as follows:

Cash$1,016 
Common stock27,408 
Total purchase consideration$28,424 

The Company incurred $410 in transaction costs related to the acquisition, which primarily consisted of legal and accounting expenses. The acquisition-related expenses were recorded in general and administrative expenses on the consolidated statements of operations.

During the fourth quarter of 2025, the Company adjusted the purchase price allocation as a result of certain measurement period adjustments to the acquired assets and liabilities assumed. The Company finalized its measurement period accounting after filing Atomic Alchemy's short year 2025 federal and state income tax returns, and following revisions to internal estimates and new information obtained about facts and circumstances that existed as of the Acquisition Date. The measurement period adjustments included a decrease in deferred tax liabilities of $99 with a corresponding decrease to goodwill.

The purchase price allocation resulted in the following amounts being allocated to the assets acquired and liabilities assumed at the Acquisition Date based upon their respective fair values as summarized below:
Cash$116 
Prepaid expenses99 
Property and equipment40 
Operating lease right-of-use assets19 
Indefinite-lived intangible assets27,500 
Goodwill6,621 
Operating lease liability(19)
Other current liabilities(268)
Deferred tax liabilities(5,684)
Net assets acquired
$28,424 

The Company utilized an independent appraisal firm to assist in the determination of the fair values of the assets acquired and liabilities assumed, which required certain significant management assumptions and estimates. The fair value of the indefinite-lived intangible assets representing IPR&D were valued using a pre-tax royalty for the hypothetical use of a trade name for a selected royalty rate based on a market licensing agreement bench marketing analysis.

The IPR&D consisted of two separate projects, Abundantia and Meitner. Abundantia’s fair value assigned of $4,600 is expected to produce revenue potentially as early as 2026 from the sale of purified radium and other desired radioisotopes produced via irradiation. Meitner’s fair value of $22,900 is a later stage project which will produce for sale isotopes that are prepared and irradiated into radioisotopes in Versatile Isotope Production Reactors (“VIPR”), which is a thermal pool-type nuclear reactor. Each project has a different risk profile, cash flows, and its own unique process. Abundantia is expected to produce revenue upon completion of a lab, with its fair value determined using a risk-adjusted cash flow approach applied to its potential cash flows, subject to certain possession permit required by the NRC. Meitner is expected to produce revenue once a facility is constructed, with its fair value determined using a risk-adjusted cash flow approach applied to its cash flows, subject to approval of an application for a construction license and operating license by the NRC. There was no estimated useful life assigned given the assets are IPR&D.

The excess of the purchase price over the fair value amounts assigned to the assets acquired and liabilities assumed represents goodwill from the acquisition. Goodwill is recorded as a noncurrent asset that is not amortized but is subject to an annual review for impairment. Goodwill is not deductible for tax purposes.

The results of operations of Atomic Alchemy are included in the consolidated financial statements beginning on the Acquisition Date. For the year ended December 31, 2025, the consolidated statements of operations include no revenue and an immaterial amount of loss from operations for Atomic Alchemy. The Company has not presented supplemental pro forma revenue (as no revenue has been generated) and earnings of the combined business as the acquisition of Atomic Alchemy is not material to the Company’s consolidated financial statements.

Recapitalization

On May 9, 2024, in connection with the Recapitalization, the Company issued 43,099,811 shares of its common stock in accordance with the Merger Agreement (consisting of 12,500,000 shares representing the AltC founder shares that were subject to forfeiture pursuant to certain vesting events, all of which vested during the fourth quarter of 2024, 1,450,000 shares issued in exchange for AltC private placement shares, and 29,149,811 shares to the AltC public stockholders that represented the common stock subject to redemption held by the AltC stockholders immediately before the Recapitalization), for the net assets from the Recapitalization totaling $258,955, as reflected on the consolidated statement of stockholders' equity for the year ended December 31, 2024.

In connection with the Recapitalization, the Company issued 8,407,894 shares of its common stock upon conversion of the simple agreements for future equity reflecting a change in fair value upon conversion totaling $84,138, as reflected on the consolidated statement of stockholders’ equity for the year ended December 31, 2024.

See Note 9—Stockholders’ Equity for further details related to the Recapitalization for the issuance of the earnout shares (the “Earnout Shares”) where certain triggering events occurred during the fourth quarter of 2024 requiring the issuance of the Earnout Shares.
v3.26.1
Balance Sheet Components
 12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Balance Sheet Components Balance Sheet Components
Prepaid and Other Current Assets
Prepaid and other current assets are summarized as follows:
As of December 31,
20252024
Prepaid expense$18,853 $2,119 
Accrued interest receivable4,976 1,138 
Other1,969 868 
Total prepaid and other current assets$25,798 $4,125 

Prepaid expenses include prepaid consulting fees, insurance premiums, rent and other charges, and construction deposits.

Prepaid expenses are amortized over the straight-line method over the contract term. Construction deposits are reclassified to construction in progress and capitalized when the related work is performed.
Property, Plant and Equipment, Net
Property, plant and equipment, net are summarized as follows:
As of December 31,
Estimated Useful Lives (Years)20252024
Computers and equipment
3 - 7
$366 $366 
Furniture, fixtures and machinery7483 146 
Software31,405 1,020 
Leasehold improvements*62 45 
LandN/A5,145 — 
Total property and equipment, gross7,461 1,577 
Less: Accumulated depreciation and amortization(897)(375)
Construction in progress and equipment deposits35,748 — 
Total property, plant and equipment, net$42,312 $1,202 
* Shorter of lease term or estimated useful life of the asset.
Included in property, plant, and equipment is construction in progress and equipment deposits. Costs related to construction of capital projects are accumulated in construction in progress and equipment deposits until the project is complete, as well as equipment that is not yet placed in service. A construction project is considered substantially complete upon the cessation of construction and development activities. Once the project is substantially complete and ready for its intended use these costs will be amortized over the asset’s estimated useful life.

Depreciation and amortization expenses for the years ended December 31, 2025 and 2024 totaled $522 and $268, respectively.

Other Assets

Other assets are summarized as follows:
As of December 31,
20252024
Other$217 $140 
Other investments12,086 — 
Total other assets$12,303 $140 
As of December 31, 2025, the Company’s other investments, as described in Note 1, were in simple agreements for future equity and preference shares.

Accrued Expenses and Other
Accrued expenses and other are summarized as follows:
As of December 31,
20252024
Accrued professional fees$1,838 $652 
Accrued payroll and bonuses10,998 636 
General accrued expenses7,210 134 
Other current liabilities451 463 
Total accrued expenses and other$20,497 $1,885 
v3.26.1
Leases
 12 Months Ended
Dec. 31, 2025
Leases [Abstract]  
Leases Leases
As of December 31, 2025, the Company had commercial real estate lease agreements for office space and facilities under operating leases.

The table below presents supplemental information related to the operating leases:
Years Ended December 31,
20252024
Cash payments included in the measurement of operating lease liabilities during the year$862$289
Operating lease liabilities arising from obtaining lease right-of-use assets during the year$1,143$1,185
Weighted-average remaining lease term (in months) as of year-end2924
Weighted-average discount rate during the year8.91 %8.76 %

The Company utilizes its incremental borrowing rates on a collateralized basis, reflecting the Company’s credit quality and the term of the lease at the commencement of the lease in determining the present value of future payments since the implicit rate for the Company’s leases is not readily determinable.

Variable lease expense includes lease payments that vary based on usage or performance and are not fixed at lease commencement. Payments for services such as maintenance, utilities, and real estate taxes are accounted for as non-lease components and expensed as incurred.

The components of operating lease costs were as follows:
Years Ended December 31,
20252024
Operating lease costs included in:
Research and development$841 $234 
General and administrative321 87 
Total operating costs (1)$1,162 $321 

(1) Month-to-month lease arrangements for the years ended December 31, 2025 and 2024 of $276 and $184, respectively, are included in the captions within operating lease costs.

The minimum lease payments below do not include non-lease components, which are contractual obligations under the Company’s lease, but are not fixed and can fluctuate from year to year and are expensed as incurred.

As of December 31, 2025, future maturities of the operating lease liabilities were as follows :
2026$990 
2027203 
2028191 
2029199 
203034 
Minimum lease payments1,617 
Less imputed interest(167)
Present value of operating lease liabilities$1,450 
Current portion of operating lease liabilities$904 
Noncurrent portion of operating lease liabilities546 
Total operating lease liabilities$1,450 
v3.26.1
Financial Instruments
 12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Financial Instruments Financial Instruments
The following tables show the Company’s cash, cash equivalents, and marketable debt securities by significant investment category:

As of December 31, 2025
Amortized CostUnrealized GainsFair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $11,022 $— $— 
Level 1:
Money market funds— — — 777,423 — — 
U.S. Treasury securities504,008 1,123 505,131 — 320,563 184,568 
Subtotal504,008 1,123 505,131 777,423 320,563 184,568 
Level 2 (1):
Commercial paper118,907 56 118,963 — 118,963 — 
Total $622,915 $1,179 $624,094 $788,445 $439,526 $184,568 

(1) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.

As of December 31, 2025, interest receivables related to available-for-sale marketable debt securities of $4,005 were included in marketable debt securities on the consolidated balance sheets.
As of December 31, 2025, interest receivables related to marketable debt securities of $3,160 were included in prepaid expenses and other current assets on the consolidated balance sheets.

The following table shows the fair value of the Company’s marketable debt securities, by contractual maturity, as of December 31, 2025:

Due within 1 year$439,526 
Due after 1 year through 5 years184,568 
Total fair value$624,094 

As of December 31, 2024
Amortized Cost
Unrealized Gains
Unrealized Losses (1)
Fair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $— $3,020 $— $— 
Level 1:
Money market funds— — — — 94,112 — — 
U.S. Treasury securities156,040 1,688 (6)157,722 — 110,249 47,473 
Subtotal156,040 1,688 (6)157,722 94,112 110,249 47,473 
Level 2 (2):
Commercial paper19,902 531 — 20,433 — 20,433 — 
Total $175,942 $2,219 $(6)$178,155 $97,132 $130,682 $47,473 

(1) There was no allowance for expected credit losses on available-for-sale marketable debt securities as of December 31, 2024 as the unrealized losses were deemed to be temporary in nature.

(2) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.

As of December 31, 2024, interest receivables related to marketable debt securities of $826 were included in prepaid expenses and other current assets on the consolidated balance sheets.
v3.26.1
Simple Agreements for Future Equity
 12 Months Ended
Dec. 31, 2025
Other Liabilities Disclosure [Abstract]  
Simple Agreements for Future Equity Simple Agreements for Future Equity
The Company issued simple agreements for future equity prior to the Recapitalization, where the simple agreements for future equity allowed investors to purchase equity at a negotiated price at the time of each investor’s entry into such agreement with each investor receiving equity in the future with no set time for conversion. The simple agreements for future equity converted in connection with the Recapitalization. Prior to the conversion, the simple agreements for future equity were classified as a liability under ASC 480, Distinguishing Liabilities from Equity.

During the year ended December 31, 2024, the Company issued simple agreements for future equity in exchange for aggregate cash proceeds of $10,232. No simple agreements for future equity were issued during the year ended December 31, 2025.

Fair Value Measurements

Prior to the simple agreements for future equity conversion, they were measured at fair value on a recurring basis using significant unobservable inputs based upon a three-tier hierarchy under the authoritative guidance (Level 3) at each reporting period-end, with changes in the fair value recognized on the consolidated statements of operations. The change in fair value during the year ended December 31, 2024 was $27,864 as reflected on the consolidated statements of operations.
v3.26.1
Right of First Refusal Liability
 12 Months Ended
Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]  
Right of First Refusal Liability Right of First Refusal Liability
On February 16, 2024, the Company entered into a letter of intent (the “LOI”) with an unrelated third party (the “third party”) for the purchase of power from the Company’s planned powerhouses to serve certain data centers in the U.S. on a
20-year timeline with the right to renew for additional 20-year terms, and at a rate to be formally specified in one or more future power purchase agreement ("PPA") (subject to the requirement that the price meets certain conditions contained in the agreement).

The LOI provides for the third party to have a continuing right of first refusal for a period of thirty-six (36) months following its execution to purchase energy output produced by certain powerhouses developed by the Company in the U.S., subject to certain provisions and excluded powerhouses (the “ROFR”). In exchange for the ROFR and other rights contained in the LOI, in March 2024, the third party paid the Company $25,000 (the “Payment”). In connection with the Payment, the Company agreed to supply power at a discount to the most favored nation pricing that the Company is required to provide to the third party in a future PPA (location to be determined); provided, that pricing set out in a PPA will include an additional discount if needed such that the total savings against most favored nation pricing over the course of the PPA is equivalent to the Payment. The Payment is effectively a nonrefundable upfront payment that will be attributed to future power delivery. As of December 31, 2025, the outstanding balance under the right of first refusal liability was $25,000, as reflected on the consolidated balance sheets.
v3.26.1
Stockholders’ Equity
 12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Stockholders’ Equity Stockholders’ Equity
Pursuant to the Second Amended and Restated Certificate of Incorporation of the Company dated May 9, 2024, the Company is authorized to issue 501,000,000 shares of all classes of capital stock consisting of (i) 500,000,000 shares of Class A common stock, par value of $0.0001 per share ("common stock"), and (ii) 1,000,000 shares of preferred stock, par value of 0.0001 per share. Subject to the special rights of the holders of any outstanding series of preferred stock, the number of shares of preferred stock may be increased or decreased (but not below the number of shares then outstanding) by affirmative vote of the holders of a majority of the stock of the Company entitled to vote. There are no shares of preferred stock issued and outstanding.

Common Stock

The holders of common stock have one vote for each share of common stock held of record by such holder as of the applicable record date. Subject to the special rights of holders of any outstanding preferred stock to elect directors, there were seven (7) directors at the time of filing the Restated Certificate of Incorporation. Thereafter, the number of directors will be exclusively fixed from time to time by resolution of a majority of the Company’s board of directors (the “Board”). Subject to the special rights of holders of any outstanding series of preferred stock to elect directors, the Board is divided into three classes with the term of each director expiring on the date of the third annual meeting of stockholders following the annual meeting of stockholders at which such director was elected, as follows: Class I, with a term expiring at the first annual meeting; Class II, with a term expiring at the second annual meeting; and Class III, with a term expiring at the third annual meeting.

Reserve of Common Stock – As of December 31, 2025, the Company reserved the following shares of its common stock: (i) 6,468,440 shares of common stock issuable upon the exercise of outstanding options under the Oklo Inc. 2016 Stock Incentive Plan (the “Legacy Oklo 2016 Plan”); (ii) 12,805,133 shares of common stock issuable for potential future awards, subject to certain annual increases commencing on January 1, 2025 and ending on January 1, 2034, under the Oklo Inc. 2024 Equity Incentive Plan (the “2024 Plan”); and (iii) 2,441,926 shares of common stock authorized for future issuance, subject to certain annual increases commencing on January 1, 2025 and ending on January 1, 2034, under the Oklo Inc. 2024 Employee Stock Purchase Plan (the “2024 ESPP”). See Note 10—Stock-based Compensation for further details of the Legacy Oklo 2016 Plan, the 2024 Plan and 2024 ESPP.

Equity Offering

Common Stock Public Offering – On June 16, 2025, the Company raised gross proceeds of $460,000 pursuant to a firm commitment underwritten public offering of 7,666,667 shares of the Company’s common stock (6,666,667 shares were issued on June 16, 2025 and an additional 1,000,000 shares were issued pursuant an exercise on June 13, 2025 in connection with the underwriters’ exercise of a 30-day overallotment option in full), at a public offering price of $60.00 per share. The Company received net proceeds of $441,600 upon the sale of its common stock, (net of underwriting discounts and commissions totaling $18,400) and other offering costs of $1,498 payable by the Company, representing $440,102 as reflected on the consolidated statements of stockholders’ equity.

ATM Programs

On June 2, 2025, the Company entered into a sales agreement with sales agents pursuant to which the Company may offer and sell, from time to time and at its sole discretion, shares of the Company’s common stock up to an aggregate gross sales price of $400,000 through the sales agents in an “at-the-market” ("ATM") offering (the “June ATM Program”). Under the
June ATM Program, the Company agreed to pay the sales agents commissions at a rate equal to 2.5% of the aggregate gross proceeds from each sale of shares. From August 2, 2025 to August 27, 2025, the Company sold 5,458,953 shares of its common stock through the sales agents at an average price of $73.27 per share, resulting in aggregate gross proceeds of $400,000.

Under the June ATM Program the Company filed a new prospectus supplement on September 3, 2025, increasing the aggregate offering amount by up to $139,999 bringing the total potential aggregate gross proceeds under the updated June ATM Program to approximately $539,999. From September 5, 2025 to September 11, 2025, the Company sold 1,925,066 shares of its common stock through the sales agents at an average price of $72.72 per share, resulting in aggregate gross proceeds of $139,999. No additional shares will be sold under this June ATM Program unless an additional prospectus supplement is filed.

On December 4, 2025, the Company entered into an sales agreement with sales agents pursuant to which the Company may offer and sell, from time to time and at its sole discretion, shares of its common stock up to an aggregate gross sales price of $1,500,000 in an ATM offering (the "December ATM Program"). During December 2025, the Company sold 3,397,872 shares of common stock through the sales agents at an average price of $88.29 per share, resulting in aggregate gross proceeds of $300,000. Under the December ATM Program, the Company agreed to pay the sales agents commissions at a rate equal to 1.5% of the aggregate gross proceeds from each sale of shares. The December ATM Program remains open and additional shares can be sold.

During the year ended December 31, 2025, the Company offered and sold 10,781,891 shares of its common stock through the ATM programs for net proceeds of $821,999 (net of sales agents commissions of $18,000) and other issuance costs of $1,635 payable by the Company representing $820,364 as reflected on the consolidated statements of stockholders’ equity.

Stock Plans

Exercise of Stock Options – During the year ended December 31, 2025, the Company issued shares of its common stock upon the exercise of stock options totaling 2,759,216, with proceeds of $4,028, as reflected on the consolidated statements of stockholders’ equity. During the year ended December 31, 2024, the Company issued shares of its common stock upon the exercise of stock options totaling 2,256,157, with proceeds of $1,044, as reflected on the consolidated statements of stockholders’ equity.

Restricted Stock Units – The Company issued, in connection with the vesting of restricted stock units, 571,741 shares of the Company’s common stock during the year ended December 31, 2025, as reflected on the consolidated statements of stockholders’ equity.

Common Stock Withheld for Taxes – The Company withheld 67,187 shares of its common stock upon issuance of vested restricted units, representing a payment for taxes of $1,647 during the year ended December 31, 2025, as reflected on the consolidated statements of stockholders’ equity.
Issuance of Common Stock Related to Earnout Awards – In connection with the Recapitalization, as discussed in Note 3, the Company issued 14,699,794 shares of its common stock related to the Earnout Shares during the year ended December 31, 2024 as a result of certain earnout triggering events, including 433,348 shares of its common stock that were attributable to Legacy Oklo vested options. See Note 10—Stock-based Compensation for further details.
v3.26.1
Stock-based Compensation
 12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Stock-based Compensation Stock-based Compensation
Legacy Oklo 2016 Plan – Under the Legacy Oklo 2016 Plan only stock options have been awarded. The options with a time-based vesting schedule vest at the rate of 20% per year over a period of 5 years, beginning one year following the related grant date, and expire ten years from the date of the grant. Options with milestone-based vesting vest upon completion of milestones specific to each grant. Effective as of May 9, 2024, the Company is no longer issuing new awards under the Legacy Oklo 2016 Plan. As of December 31, 2025, options to purchase 6,468,440 shares of common stock were outstanding under the Legacy Oklo 2016 Plan.

2024 Plan – The 2024 Plan provides for the issuance of stock options (which may be incentive stock options or nonqualified stock options) stock appreciation rights (“SARs”), restricted stock awards, restricted stock units (“RSUs”) and other stock-based awards to eligible employees, consultants, advisors and non-employee directors. Awards under the 2024 Plan cover shares of common stock. Stock options and SARs granted pursuant to the 2024 Plan are subject to a maximum term of ten (10) years. Since the 2024 Plan’s inception, only RSUs have been awarded under the 2024 Plan. The 2024 Plan
will terminate automatically ten (10) years after its adoption by the Board. As of December 31, 2025, 2,857,390 restricted stock units were outstanding under the 2024 Plan, of which 433,912 have vested and 2,423,478 remain unvested.

2024 ESPP – The 2024 ESPP provides eligible employees with an opportunity to purchase common stock from the Company at a pre-determined discounted price and to pay for such purchases through payroll deductions or other approved contributions during “offering periods” under the 2024 ESPP. The 2024 ESPP will terminate automatically twenty (20) years after its adoption by the Board. As of December 31, 2025, the Company has not granted any rights to purchase common stock under the 2024 ESPP.

Compensation costs was estimated for stock options based on the grant date fair value using a Black-Scholes option valuation model, consistent with authoritative guidance utilizing the following assumptions for the year ended December 31, 2024:

Expected volatility79.67 %
Expected dividend yield0 %
Risk-free interest rate4.08 %
Expected term6.3 years

Expected Volatility – Legacy Oklo determined volatility based on the historical volatilities of comparable publicly traded companies over a period equal to the expected term because it has no trading history for its common stock price. The comparable companies were chosen based on the similar size, stage in the life cycle, or area of specialty. The Company will continue to apply this process until a sufficient amount of historical information regarding volatility on its own stock becomes available. For certain stock option award modifications during 2025, the expected volatility was based on evaluating the Company’s implied volatility given sufficient historical information regarding volatility was available.

Expected Dividend Yield – The Company has not, and does not, intend to pay dividends.

Risk-free Interest Rate – The Company applies the risk-free interest rate based on the U.S. Treasury yield in effect at the time of the grant consistent with the expected term of the award.

Expected Term – The Company calculated the expected term using the simplified method. This method uses the average of the contractual term of the option and the weighted-average vesting period in accordance with authoritative guidance.

Fair Value of Common Stock – The grant date fair market value of the Legacy Oklo shares of common stock underlying stock options has historically been determined by the Legacy Oklo’s board of directors (the “Legacy Oklo Board”). Prior to the Recapitalization, there was no public market for the Company’s common stock, therefore, the Legacy Oklo Board exercised reasonable judgment and considered a number of objective and subjective factors to determine the best estimate of the fair market value, which included contemporaneous valuations performed by a third-party. After the Recapitalization, the closing price of the common stock on the NYSE is used as the fair value of the Company’s common stock for the issuance of restricted stock.

A summary of the stock option award activity during the year ended December 31, 2025 is as follows:

Number of SharesWeighted-Average Exercise PriceWeighted-Average Remaining Contractual Life (in years)
Common stock awards outstanding at January 1, 20259,470,382$1.95 7.91
Exercised(2,759,216)1.46 
Forfeited(242,726)3.22 
Common stock awards outstanding at December 31, 20256,468,4402.11 7.25
Common stock awards exercisable at December 31, 20252,508,6681.65 6.76
Common stock awards not vested at December 31, 20253,959,772
As of December 31, 2025, an aggregate of 12,805,133 shares of common stock were authorized for issuance under the 2024 Plan, of which 2,857,390 shares were reserved for issuance upon vesting and settlement of outstanding restricted stock units.

The aggregate grant date fair values of stock options granted during the year ended December 31, 2024 was $1,108. The weighted-average grant-date fair value of stock options granted during the year ended December 31, 2024 was $3.15. No stock options were granted during the year ended December 31, 2025.

The intrinsic value for stock options exercised represents the difference between the fair value based on the valuation of the shares of common stock as of the reporting date and the exercise price of the stock option. The total intrinsic values of stock options exercised during the years ended December 31, 2025 and 2024 were $188,386 and $28,537, respectively. The total fair value of stock options vested during the years ended December 31, 2025 and 2024 were $4,183 and $2,916, respectively.

As of December 31, 2025, the intrinsic value of exercisable, in-the-money stock options was $175,873, and the aggregate intrinsic value of all outstanding, in-the-money options, including both exercisable and unvested options, was $450,533, both based on the fair market value of the Company’s common stock trading price at December 31, 2025 of $71.76 per share.

Effective on April 1, 2025, the Company modified a stock option award for one employee from a performance-based vesting condition to time-based vesting condition that provides for equal monthly vesting over five years. This modification resulted in incremental stock‑based compensation cost of $10,234.

A summary of restricted stock unit award activity during the year ended December 31, 2025 is as follows:

Number of Units
Weighted-Average Grant Date Fair Value
 
Unvested
Vested
Restricted stock units outstanding at January 1, 20251,252,166 134,832 $8.02
Granted2,081,611— 53.51
Vested
(870,821)870,821 26.07
Issued— (571,741)—
Forfeited(39,478)— 15.95
Restricted stock units outstanding at December 31, 20252,423,478433,912 37.84

The aggregate grant date fair value of restricted stock units that vested during the year ended December 31, 2025 was $22,705.
During 2025, the Company approved modifications to equity awards in connection with employee termination events. These modifications included the acceleration of vesting for certain stock options for two former employees, full vesting of outstanding RSU awards, and an extension of the post‑termination exercise period for one former employee. These modifications altered the vesting conditions of the affected awards. This modification resulted in incremental stock‑based compensation cost of $4,765.

The Company also approved a modification to an equity award for an employee who transitioned to a consulting arrangement during 2025. In connection with this change in employment status, the Company accelerated vesting of the employee’s restricted stock unit awards and certain stock options along with the replacement of the employees’ unvested outstanding on stock options with an equivalent number of restricted stock unit awards subject to vesting over the consulting service period. These changes altered both the form and vesting conditions of the awards. This modification resulted in incremental stock‑based compensation cost of $10,832.

In connection with the Recapitalization on May 9, 2024, as discussed in Note 3, the Company recorded incremental stock-based compensation cost related to the modification of Legacy Oklo vested options that were outstanding at that time, reflecting the holders’ contingent right to receive a pro rata share of the Earnout Shares. This modification resulted in incremental stock‑based compensation cost of $7,784.
A summary of unvested restricted stock award activity during the year ended December 31, 2025 is as follows:
​
Unvested Number of UnitsWeighted Average Grant Date Fair Value
Restricted stock awards outstanding at January 1, 2025—$— 
Granted274,33933.39 
Restricted stock awards outstanding at December 31, 2025274,33933.39

Stock-based compensation costs charged to operations is summarized as follows:
Years Ended December 31,
20252024
Research and development$12,251 $7,797 
General and administrative29,544 4,687 
Total costs charged to operations$41,795 $12,484 

Unrecognized stock-based compensation costs and expected weighted-average period to be recognized related to the stock-based compensation awards as of December 31, 2025 is presented below:

Restricted StockStock OptionsTotals
Unrecognized stock-based compensation cost$96,989 $14,933 $111,922 
Weighted-average period over which cost is expected to be recognized (in years)3.443.553.46
v3.26.1
Income Taxes
 12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The components of income tax (benefit) expense consist of the following:

As of December 31,
Current tax expense:
2025
2024
Federal$— $— 
State and local— 683 
Total current tax expense— 683 
Deferred tax benefit:
Federal(3,516)— 
State and local(1,013)— 
Total deferred tax benefit(4,529)— 
Total income tax (benefit) expense$(4,529)$683 

Significant components of the Company’s deferred taxes are as follows:
As of December 31,
20252024
Deferred tax assets:
Net operating loss carryforwards $5,599 $3,078 
R&D tax credit10,692 2,443 
Capitalized R&D expenses16,039 5,617 
Capitalized start-up expenses34,210 15,628 
Advance payment5,267 — 
Operating lease liabilities305 216 
Stock-based compensation2,598 394 
Other15 73 
Accrued expenses2,079 — 
Deferred tax assets76,804 27,449 
Valuation allowance(71,625)(26,775)
Total deferred tax assets5,179 674 
Deferred tax liabilities:
Indefinite-lived intangible assets(5,794)— 
Right-of-use assets(292)(207)
Unrealized gain on marketable debt securities(248)(467)
Total deferred tax liabilities(6,334)(674)
Net deferred tax liabilities$(1,155)$— 

The Company regularly assesses the ability to realize deferred tax assets recorded based upon the weight of available evidence, including such factors as recent earnings history, and expected future taxable income on a jurisdiction by jurisdiction basis. In the event that the Company changes its determination as to the amount of realizable deferred tax assets, the Company will adjust its valuation allowance with a corresponding impact to the income tax (benefit) in the period in which such determination is made. Due to the uncertainty surrounding their realization, the Company has recorded a valuation allowance primarily against its deferred tax assets up to certain deferred tax liabilities as of December 31, 2025 and 2024.

On July 4, 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted into law, introducing significant changes to U.S. corporate income tax provisions. The effects of changes in tax laws are recognized in the period of enactment, which were primarily related to amendments to Section 174. The impact of OBBBA on income tax (benefit) expense for the year ended December 31, 2025 was not material.

As of December 31, 2025 and 2024, the Company’s unamortized capitalized R&D expenses of approximately $76,130 and $26,770, respectively, will be amortized in varying amounts through 2034 for tax purposes. As of December 31, 2025 and 2024, the Company capitalized certain start-up costs of approximately $162,370 and $74,040, respectively, that will be amortized, subject to certain limitations, over a 180-month period beginning with the month in which the Company is considered to be in an active trade or business for tax purposes.

As of December 31, 2025, the Company had net operating loss carryforwards for federal income tax purposes of $23,694 and $9,748 for state and local income tax purposes. Net operating losses for federal purposes of approximately $22,073 do not expire (limited to 80% of taxable income in a given year). As of December 31, 2024, the Company had net operating loss carryforwards for federal income tax purposes of $14,739 and the Company’s state net operating loss carryforwards were not material.

As of December 31, 2025 and 2024, the Company had federal research credit carryforwards of approximately $12,128 and $2,714, respectively. The federal research credit carryforwards will expire at various dates beginning in the year 2035. The Company may be entitled to claim additional state income tax credits for its R&D activities, but these amounts have not yet been determined. Any additional state R&D tax credits generated by the Company would result in an additional deferred tax asset, unless utilized, that would be subject to a full valuation allowance.

The Internal Revenue Code of 1986, as amended, imposes restrictions on the utilization of net operating losses in the event of an “ownership change” of a corporation. Accordingly, a Company’s ability to use net operating losses may be limited as prescribed under Internal Revenue Code Section 382 (“Section 382”). Events which may cause limitations in the amount of
the net operating losses that the Company may use in any one year include, but are not limited to, a cumulative ownership change of more than 50% over a three-year period. Utilization of the federal and state net operating losses may be subject to substantial annual limitation due to the ownership change limitations provided by the Section 382 and similar state provision.

The Company files income tax returns in the U.S. federal and various state jurisdictions, each of which is subject to differing statutes of limitations. The Company is generally no longer subject to tax examinations for years prior to 2022 for federal purposes and 2021 for state purposes, except in certain state jurisdictions. However, net operating losses generated in tax years beginning in 2014 remain subject to examination to the extent such losses are utilized in future periods.

The benefit for income taxes differs from the amount obtained by applying the federal statutory income tax rate as follows:

Years Ended December 31,
20252024
AmountPercentAmountPercent
U.S. federal statutory tax rate $(23,140)21.0 %$(15,316)21.0 %
State and local taxes, net of federal benefit (a)
(1,013)0.9 %539 (0.7)%
Effect of change in tax laws or rates enacted in current period— — %— — %
Tax credits
R&D tax credits(9,359)8.5 %(1,290)1.8 %
Change in valuation allowances43,952 (39.9)%16,011 (21.3)%
Nontaxable and nondeductible items
Nondeductible executive compensation10,275 (9.3)%242 (0.3)%
Change in fair value of simple agreements for future equity— — %5,852 (8.0)%
Transaction costs— — %(1,555)2.1 %
Interest expense— — %(1,190)1.6 %
Stock-based compensation(26,750)24.3 %(2,981)4.1 %
Other342 (0.3)%100 (0.8)%
Changes in unrecognized tax benefits1,164 (1.1)%271 (0.4)%
Effective tax rate$(4,529)4.1 %$683 (0.9)%
(a) State taxes in Idaho and California made up the majority (greater than 50 percent) of the tax effect in this category for the tax years ended December 31, 2025 and 2024, respectively.

The effective tax rate for 2025 is lower than the statutory U.S. federal tax rate primarily due to a full valuation allowance against U.S. deferred tax assets, as well as the impact of stock-based compensation and nondeductible executive compensation.

The following table represents a roll forward of the qualifying accounts consisting of the valuation allowance for deferred tax assets:

Years Ended December 31,
20252024
Valuation allowance for deferred tax assets - beginning of year$26,775 $11,184 
Change in valuation allowance recognized in the provision for federal income taxes for the year43,952 16,011
Change in valuation allowance recognized in provision for state and local income taxes for during the year679 47 
Change in valuation allowance recognized to other accounts219 (467)
Valuation allowance for deferred tax assets - end of year$71,625 $26,775 

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
Years Ended December 31,
20252024
Balance at beginning of year$271 $— 
Additions for tax positions taken in prior year228 142 
Additions for tax positions related to the current year936 129
Balance at end of year$1,435 $271 

If the unrecognized tax benefits are fully recognized in the future, there would be no impact to the effective tax rate, and $1,435 would result in adjustments to the valuation allowance. Interest and penalties related to unrecognized tax benefits were insignificant in the period presented.

Income taxes paid consisted of the following:
Years Ended December 31,
20252024
Federal$ * $223 
California2,464 550 
New York City*123 
Other*11 
Total$2,464 $907 
* Represents jurisdictions below for the threshold for the years presented.
v3.26.1
Retirement Plan
 12 Months Ended
Dec. 31, 2025
Retirement Benefits [Abstract]  
Retirement Plan Retirement Plan
The Company has a qualified 401(k) defined contribution plan that allows eligible employees of the Company to participate in the plan, subject to limitations. The plan allows for discretionary matching contributions by the Company, up to 4% of eligible annual compensation made by participants of the plan. The Company contributions to the plan were $820 and $487 for the years ended December 31, 2025 and 2024, respectively.
v3.26.1
Commitments and Contingencies
 12 Months Ended
Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies Commitments and Contingencies
Contract Commitments
The Company enters into contracts and purchase obligations in the normal course of business with third-party contract research organizations, contract development and manufacturing organizations and other service providers and vendors. These contracts generally provide for termination on notice and, therefore, are cancellable contracts and not considered contractual obligations and commitments. Purchase obligations include contracts for construction projects, selling and administrative services, and capital expenditures.
Contingencies
From time to time, the Company may become involved in litigation matters arising in the ordinary course of business. The Company is not a party to any legal proceedings, nor is it aware of any material pending or threatened litigation. There were no contingent liabilities as of December 31, 2025.
v3.26.1
Segment Information
 12 Months Ended
Dec. 31, 2025
Segment Reporting [Abstract]  
Segment Information Segment Information
In accordance with criteria under ASC 280, which establishes standards for companies to report in their financial statement information about operating segments, products, services, geographic areas, and major customers, the Company’s chief operating decision maker (“CODM”) has been identified as the Chief Executive Officer. The Company’s CODM reviews consolidated results to assess performance, make decisions, and allocates operating and capital resources of the Company as a whole, therefore, there is only one reportable segment. The CODM does not distinguish its principal business activities for the purpose of internal reporting and uses net loss to allocate resources in the annual budgeting and forecasting process, along with using that measure as a basis for evaluating financial performance quarterly by comparing the actual results with historical budgets.
Significant segment expenses that are provided to CODM on a regular basis and are included within reported measure of segment profit or loss are research and development and general and administrative. Other segment items are represented by change in fair value of simple agreements for future equity, interest and dividend income and income taxes.
The consolidated statements of operations for the years ended December 31, 2025 and 2024, reflect the significant segment expenses and other segment items, as well as the consolidated balance sheets as of December 31, 2025 and 2024, for the one reportable segment.
v3.26.1
Related Party Transactions
 12 Months Ended
Dec. 31, 2025
Related Party Transactions [Abstract]  
Related Party Transactions Related Party Transactions
On June 25, 2025, the Company entered into an agreement under which M. Klein & Company, through its affiliate, The Klein Group LLC, will provide financial advisory and strategic services. Mr. Michael Klein, who currently serves as a director of the Company, maintains a direct controlling interest in M. Klein & Company. The advisory agreement is for a term of one year and requires the Company to pay a $250 quarterly retainer fee, in addition to other potential fees depending on the outcomes of certain transactions. During the year ended December 31, 2025, the Company made total payments of $500 under the agreement.
v3.26.1
Subsequent Events
 12 Months Ended
Dec. 31, 2025
Subsequent Events [Abstract]  
Subsequent Events Subsequent Events
The Company performed an evaluation of subsequent events through the date of filing of these consolidated financial statements with the SEC. Other than the subsequent events described below, there were no material subsequent events which affected, or could affect, the amounts or disclosures on the consolidated financial statements.

ATM Program

In connection with the December ATM Program, an additional 12,376,352 shares of common stock were sold under the program from January 1 through its closure on January 28, 2026 at an average price of $96.95 per share, resulting in aggregate gross proceeds of $1,199,868, subject to sales agent commissions.

Prepayment Agreement

On January 5, 2026, we entered into a prepayment agreement (the "Prepayment Agreement") with Meta Platforms, Inc. (“Meta”) that advances plans to develop a 1.2 gigawatt power campus in Pike County, Ohio, to support Meta’s data centers. The Prepayment Agreement provides a mechanism for Meta to prepay for power and provide funding to advance powerhouse deployment. Pursuant to the Prepayment Agreement, the Company will use Meta's funding to secure nuclear fuel, advancing the first phase of the project.
v3.26.1
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
William Goodwin [Member]  
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement On December 15, 2025, William Goodwin, the Company’s Chief Legal and Strategy Officer, adopted a Rule 10b5-1 trading arrangement (the “Trading Arrangement”) intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. The Trading Arrangement is intended to provide for “eligible sell-to-cover transactions” (as described in Rule 10b5-1(c)(1)(ii)(D)(3) under the Exchange Act) to satisfy tax withholding obligations arising exclusively from the vesting of equity awards and the related issuance of up to 13,620 shares of the Company’s common stock. The number of shares that will be sold to satisfy applicable tax withholding obligations upon vesting is not currently determinable as the number will vary based on the market price of the Company’s common stock and the extent to which vesting conditions are satisfied. The Trading Arrangement will terminate December 4, 2026, subject to early termination for certain specified events set forth in the Trading Arrangement.
Name William Goodwin
Title Chief Legal and Strategy Officer
Rule 10b5-1 Arrangement Adopted true
Adoption Date December 15, 2025
Expiration Date December 4, 2026
Arrangement Duration 354 days
Aggregate Available 13,620
v3.26.1
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
v3.26.1
Cybersecurity Risk Management and Strategy Disclosure
 12 Months Ended
Dec. 31, 2025
Cybersecurity Risk Management, Strategy, and Governance [Line Items]  
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]
We have developed and implemented a cybersecurity risk management program designed to protect the confidentiality, integrity, and availability of our critical systems and information. In collaboration with the Company’s IT leadership, management has established structured processes for identifying, assessing, and mitigating cybersecurity risks that may impact our business operations including processes to identify cybersecurity risks associated with the use of third-party service providers.

Senior leadership regularly provides updates to the Audit Committee of our Board on the status and outcomes of internal audits evaluating our cybersecurity systems, controls, and processes. Our program is guided by the National Institute of Standards and Technology (“NIST”) Cybersecurity Framework, which serves as a valuable resource in helping us identify, assess, and manage cybersecurity risks aligned with our business needs. This does not imply that we meet any
particular standards, specifications or requirements, only that we use NIST as a guide.

Our cybersecurity risk management program is integrated into our overall risk management program, and shared common methodologies, reporting channels, and governance processes that apply across the risk management program to other
legal, compliance, strategic, operational, and financial risk areas. Our overall strategy in protecting against cybersecurity risks includes the following preventative and detective measures:

•Multi-layered network security architecture – We have implemented firewalls, intrusion detection and prevention systems (IDPS), endpoint detection and response (EDR) solutions, and we utilize threat intelligence.

•Incident response – In the event of an incident, management has established an incident response plan designed to identify, evaluate, respond to, mitigate, and report potential cybersecurity threats, including notifying the Board or regulatory agencies, as deemed appropriate. This response plan is tested regularly and is intended to address cybersecurity risks to the corporate information technology (“IT”) environment including the Company’s systems, hardware, software, data, people, and processes.

•Regular security assessments and penetration testing – We conduct periodic vulnerability assessments and simulated cyberattack exercises to identify and remediate security weaknesses in our IT infrastructure.

•Third-party Security Operations Center (“SOC”) monitoring – We partner with a third-party SOC and incident response retainer to provide security monitoring, threat detection, and rapid incident response, ensuring proactive identification and mitigation of potential cyber threats.

•Employee cybersecurity awareness and training programs – All employees are required to participate in cybersecurity training, including phishing simulations, social engineering awareness, and secure data handling practices.

Oklo has not experienced any material cybersecurity incidents to date, and we are not aware of any threats, current or ongoing, that would materially affect or be reasonably likely to materially affect our results of operations or financial condition. We face risks from cybersecurity threats that, if realized, are reasonably likely to materially affect us, including our operations, business strategy, results of operations, or financial condition. See “Risk Factors—If we or our third-party providers fail to protect confidential information and experience data security incidents, we may experience adverse effects, including regulatory enforcement consequences, on our business and results of operations.”
Cybersecurity Risk Management Processes Integrated [Flag] true
Cybersecurity Risk Management Processes Integrated [Text Block]
Our cybersecurity risk management program is integrated into our overall risk management program, and shared common methodologies, reporting channels, and governance processes that apply across the risk management program to other
legal, compliance, strategic, operational, and financial risk areas.
Cybersecurity Risk Management Third Party Engaged [Flag] true
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 of Directors Oversight [Text Block]
The Board maintains oversight responsibility for cybersecurity risks and has delegated to the Audit Committee oversight of such risks, including oversight of management’s implementation of our cybersecurity risk management program. Management regularly reports to the Audit Committee of the Board regarding the status and outcomes of regular internal audits of cybersecurity systems, controls, and processes. As needed, management also briefs the Board on our cybersecurity environment and information security philosophy. We also review and advise our Board of cybersecurity threats to us, including emerging cybersecurity threats, as well as our plans and strategies to address them.

Our cybersecurity management team consists of the following:

•Chief Financial Officer – previously held roles associated with cybersecurity monitoring and reporting at bp plc, including being accountable for deployment of an active monitoring implementation program focused on the North American Downstream business, as well as oversight for IT when serving as the Chief Financial Officer for the NA Fuels business for bp plc and while Chief Financial Officer at Renewable Energy Group.

•Head of IT and Cyber – has over 20 years of IT leadership in cybersecurity, including risk management, incident response, and cybersecurity strategy across defense, education, and corporate sectors. He has managed IT and cyber operations for over 100,000 users, overseeing enterprise ERP, HRIS, internet services, email systems, and security operations centers. He holds certifications including CISSP, CCNP, and ITIL.

•General Counsel and Corporate Secretary – has extensive experience helping companies manage cybersecurity, privacy, and data protection related risks across the technology, e-commerce, and healthcare sectors. He has served as the global Data Protection Officer at four companies, including at Shopify Inc. where he helped respond to cybersecurity incidents, and managed all related legal and regulatory impact. He also previously managed the cybersecurity function at a Series B startup where he served as General Counsel and Corporate Secretary.
All of the above individuals have played a key role in our transition as a public company, working closely with external cybersecurity advisory specialists to evolve IT and cybersecurity practices to meet public company compliance standards.

Our management team remains actively engaged in overseeing cybersecurity risk prevention, detection, mitigation, and remediation efforts. This is achieved through regular briefings from our internal IT and cyber staff, with insights from threat intelligence sources, including governmental, public, and private entities as well as guidance from external service providers. Additionally, management reviews alerts and reports generated by advanced security tools deployed within our environment to ensure a proactive and informed approach to cybersecurity threats.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] The Board maintains oversight responsibility for cybersecurity risks and has delegated to the Audit Committee oversight of such risks, including oversight of management’s implementation of our cybersecurity risk management program. Management regularly reports to the Audit Committee of the Board regarding the status and outcomes of regular internal audits of cybersecurity systems, controls, and processes.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]
Our cybersecurity management team consists of the following:

•Chief Financial Officer – previously held roles associated with cybersecurity monitoring and reporting at bp plc, including being accountable for deployment of an active monitoring implementation program focused on the North American Downstream business, as well as oversight for IT when serving as the Chief Financial Officer for the NA Fuels business for bp plc and while Chief Financial Officer at Renewable Energy Group.

•Head of IT and Cyber – has over 20 years of IT leadership in cybersecurity, including risk management, incident response, and cybersecurity strategy across defense, education, and corporate sectors. He has managed IT and cyber operations for over 100,000 users, overseeing enterprise ERP, HRIS, internet services, email systems, and security operations centers. He holds certifications including CISSP, CCNP, and ITIL.
•General Counsel and Corporate Secretary – has extensive experience helping companies manage cybersecurity, privacy, and data protection related risks across the technology, e-commerce, and healthcare sectors. He has served as the global Data Protection Officer at four companies, including at Shopify Inc. where he helped respond to cybersecurity incidents, and managed all related legal and regulatory impact. He also previously managed the cybersecurity function at a Series B startup where he served as General Counsel and Corporate Secretary.
Cybersecurity Risk Role of Management [Text Block]
Our cybersecurity management team consists of the following:

•Chief Financial Officer – previously held roles associated with cybersecurity monitoring and reporting at bp plc, including being accountable for deployment of an active monitoring implementation program focused on the North American Downstream business, as well as oversight for IT when serving as the Chief Financial Officer for the NA Fuels business for bp plc and while Chief Financial Officer at Renewable Energy Group.

•Head of IT and Cyber – has over 20 years of IT leadership in cybersecurity, including risk management, incident response, and cybersecurity strategy across defense, education, and corporate sectors. He has managed IT and cyber operations for over 100,000 users, overseeing enterprise ERP, HRIS, internet services, email systems, and security operations centers. He holds certifications including CISSP, CCNP, and ITIL.
•General Counsel and Corporate Secretary – has extensive experience helping companies manage cybersecurity, privacy, and data protection related risks across the technology, e-commerce, and healthcare sectors. He has served as the global Data Protection Officer at four companies, including at Shopify Inc. where he helped respond to cybersecurity incidents, and managed all related legal and regulatory impact. He also previously managed the cybersecurity function at a Series B startup where he served as General Counsel and Corporate Secretary.
Cybersecurity Risk Management Positions or Committees Responsible [Flag] true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]
Our cybersecurity management team consists of the following:

•Chief Financial Officer – previously held roles associated with cybersecurity monitoring and reporting at bp plc, including being accountable for deployment of an active monitoring implementation program focused on the North American Downstream business, as well as oversight for IT when serving as the Chief Financial Officer for the NA Fuels business for bp plc and while Chief Financial Officer at Renewable Energy Group.

•Head of IT and Cyber – has over 20 years of IT leadership in cybersecurity, including risk management, incident response, and cybersecurity strategy across defense, education, and corporate sectors. He has managed IT and cyber operations for over 100,000 users, overseeing enterprise ERP, HRIS, internet services, email systems, and security operations centers. He holds certifications including CISSP, CCNP, and ITIL.
•General Counsel and Corporate Secretary – has extensive experience helping companies manage cybersecurity, privacy, and data protection related risks across the technology, e-commerce, and healthcare sectors. He has served as the global Data Protection Officer at four companies, including at Shopify Inc. where he helped respond to cybersecurity incidents, and managed all related legal and regulatory impact. He also previously managed the cybersecurity function at a Series B startup where he served as General Counsel and Corporate Secretary.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block] Chief Financial Officer – previously held roles associated with cybersecurity monitoring and reporting at bp plc, including being accountable for deployment of an active monitoring implementation program focused on the North American Downstream business, as well as oversight for IT when serving as the Chief Financial Officer for the NA Fuels business for bp plc and while Chief Financial Officer at Renewable Energy Group.
•Head of IT and Cyber – has over 20 years of IT leadership in cybersecurity, including risk management, incident response, and cybersecurity strategy across defense, education, and corporate sectors. He has managed IT and cyber operations for over 100,000 users, overseeing enterprise ERP, HRIS, internet services, email systems, and security operations centers. He holds certifications including CISSP, CCNP, and ITIL.
•General Counsel and Corporate Secretary – has extensive experience helping companies manage cybersecurity, privacy, and data protection related risks across the technology, e-commerce, and healthcare sectors. He has served as the global Data Protection Officer at four companies, including at Shopify Inc. where he helped respond to cybersecurity incidents, and managed all related legal and regulatory impact. He also previously managed the cybersecurity function at a Series B startup where he served as General Counsel and Corporate Secretary.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block] As needed, management also briefs the Board on our cybersecurity environment and information security philosophy. We also review and advise our Board of cybersecurity threats to us, including emerging cybersecurity threats, as well as our plans and strategies to address them.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] true
v3.26.1
Summary of Significant Accounting Policies (Policies)
 12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Business Combinations
Business Combinations

On May 9, 2024, the Company consummated a business combination with AltC Acquisition Corp. (“AltC”), pursuant to an Agreement and Plan of Merger and Reorganization dated July 11, 2023 (as amended, modified, supplemented, or waived, the “Merger Agreement”), resulting in a reverse recapitalization (the “Recapitalization”). Legacy Oklo was treated as the accounting acquirer, and AltC was renamed Oklo Inc. The transaction had no impact on previously reported net loss, cash flows, or total assets. See Note 3—Business Combinations—Recapitalization for additional information.

On February 28, 2025, the Company acquired Atomic Alchemy Inc. ("Atomic Alchemy"), to combine its expertise in building and operating fast reactors and nuclear fuel recycling with Atomic Alchemy’s expertise in its radioisotope business to meet the increasing demands for radioisotopes in medical, energy, industry, defense, and artificial intelligence applications. See Note 3—Business Combinations—Atomic Alchemy for additional information.
Basis of Presentation
Basis of Presentation

The accompanying financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”).
Segment Information
Segment Information

The Company has viewed its financial information on an aggregate basis for the purposes of evaluating financial performance and allocating the Company’s resources. The Company’s principal business consists primarily of research and development and deployment activities for its planned or in-process powerhouses, nuclear fuel recycling and fuel fabrication facilities, and its radioisotope production facilities. Accordingly, the Company has determined that it conducts its business in one operating and one reportable segment. For more information about the Company’s single operating and reportable segment, See Note 14 —Segment Information.
Principles of Consolidation
Principles of Consolidation
The consolidated financial statements include the Company’s accounts and those of its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated.
Use of Estimates
Use of Estimates
Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, judgments, and assumptions that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Actual results could differ materially from these estimates. On an ongoing basis, the Company evaluates its estimates, including those related to the valuation of the operating lease liabilities and operating right-of-use assets, useful lives of property, plant and equipment, valuation allowance on deferred tax assets, and fair value of acquired intangible assets and goodwill. These estimates, judgments, and assumptions are based on current and expected economic conditions, historical data, and experience available at the date of the accompanying consolidated financial statements, and various other factors that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Risks and Uncertainties
Risk and Uncertainties
The Company is subject to continuing risks and uncertainties amidst a range of supply chain, construction, and design complexities and in connection with the market dynamics around fuel costs and the current macroeconomic environment, including as a result of inflation, instability in the global banking system, trade policy (including tariffs, export controls, and sanctions), and geopolitical factors. At this point, the extent to which these effects may impact the Company’s future financial condition or results of operations is uncertain, and as of the date of issuance of these consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the update of any estimates or judgments or an adjustment of the carrying value of any assets or liabilities. These estimates may change as new events occur and additional information is obtained and will be recognized in the consolidated financial statements as soon as they become known.
Net Loss Per Common Share
Net Loss Per Common Share

The Company’s basic net loss per share of common stock is computed based on the average number of outstanding shares of common stock for the period, by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock and common share equivalents of potentially dilutive securities outstanding for the period. Potentially dilutive securities include common stock equivalents. Since the Company was in a loss position for the periods presented, basic net loss per share of common stock is the same as diluted net loss per share of common stock since the effects of potentially dilutive securities are antidilutive.
Cash and Cash Equivalents
Cash and Cash Equivalents

Cash and cash equivalents include cash and highly liquid investments in money market funds with an original contractual maturity at the date of purchase of three months or less.
Marketable Debt Securities
Marketable Debt Securities, Available-for-Sale

The Company’s investments in marketable debt securities have been classified and accounted for as available-for-sale. The Company classifies its marketable debt securities as either short-term or long-term based on each instrument’s underlying contractual maturity date. The cost of marketable debt securities is adjusted for accretion of discounts and amortization of premiums to maturity. Such accretion and amortization, as well as interest and dividends, are included in interest and dividend income. The cost of securities sold is determined using the specific identification method. Unrealized gains and
losses on marketable debt securities classified as available-for-sale are recognized in other comprehensive (loss) income on the consolidated statements of comprehensive loss.

Marketable debt securities are subject to a periodic impairment review. If the Company does not intend to sell and it is not more likely than not that it will be required to sell the security prior to recovery of its amortized cost basis, it will determine whether a decline in fair value below the amortized cost basis is due to credit-related factors. The credit loss is measured as the amount by which the debt security’s amortized cost basis exceeds the estimate of the present value of cash flows expected to be collected, up to the difference between the amortized cost basis and the fair value. Impairment is assessed at the individual security level. Credit-related impairment is recognized as an allowance in the consolidated balance sheets with a corresponding adjustment to investment income, net, in the consolidated statements of operations and comprehensive loss. Any impairment that is not credit-related is recognized in accumulated other comprehensive income in the consolidated balance sheets.
The Company does not separately measure an allowance for credit losses on accrued interest receivables on its marketable debt securities. Accrued interest receivable on available-for-sale marketable debt securities for U.S. Treasury securities are recorded in prepaid expenses and other current assets on the consolidated balance sheets. Interest receivables on available-for-sale marketable debt securities for U.S. Treasury securities (representing U.S. Treasury notes and U.S Treasury bills) and commercial paper are recorded directly within marketable debt securities on the consolidated balance sheets.
Concentration of Credit Risk
Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of cash, cash equivalents and marketable debt securities. The Company’s policy is to invest cash in institutional money market funds and marketable debt securities of the U.S. government to limit the amount of credit exposure. The Company currently maintains a portfolio of cash equivalents and marketable debt securities in money market funds and U.S. treasury securities. A portion of the Company’s operating cash is held in accounts in excess of the Federal Deposit Insurance Corporation insurance limits; however, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. The Company has not experienced any losses on cash equivalents and marketable debt securities.
Property, Plant and Equipment
Property, Plant and Equipment

Property, plant and equipment are stated at cost, net of accumulated depreciation and amortization. Expenditures for repairs and maintenance that do not improve or extend the life of the assets are expensed as incurred. When property, plant and equipment are sold or otherwise disposed of, the related cost and accumulated depreciation and amortization are removed from the respective accounts, and any resulting gains or losses are included on the consolidated statements of operations. Leasehold improvements are capitalized and amortized over the shorter of the lease term of the respective leases or estimated useful life of the asset, which includes reasonably certain renewal options.
Impairment of Long-Lived Assets
Impairment of Long-Lived Assets

The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When such events or changes in circumstances occur, the Company assesses the recoverability of long-lived assets by determining whether the carrying value of such assets will be recovered through their undiscounted expected future cash flow. If the future undiscounted cash flow is less than the carrying amount of these assets, the Company recognizes an impairment loss based on the excess of the carrying amount over the fair value of the assets. No impairment losses were recognized on any long-lived assets during the years ended December 31, 2025 and 2024.
Indefinite-Lived Intangible Assets
Indefinite-Lived Intangible Assets

Intangible assets with indefinite lives consist of in-process research and development ("IPR&D") from the Company’s acquisition of Atomic Alchemy. See Note 3—Business Combinations—Atomic Alchemy for additional information. These assets are tested annually for impairment in the fourth quarter each year, or whenever events or circumstances indicate that the carrying amount may not be recoverable, until completion or abandonment of research and development efforts associated with the projects. If potential impairment is identified, the process of evaluating the potential impairment of these assets involves significant judgment regarding estimates of the future cash flows associated with each asset. Upon
successful completion of each project, the IPR&D intangible asset is reclassified as a finite-lived intangible asset and amortized over the remaining useful life.
Goodwill
Goodwill

Goodwill represents the excess purchase consideration of an acquired business over the estimated fair value of the net assets acquired and is not amortized. Goodwill is evaluated for impairment annually in the fourth quarter each year, or whenever events or circumstances indicate that the carrying amount may not be recoverable. If the carrying amount of the Company’s reporting unit exceeds its fair value, an impairment loss is recognized for any excess of the carrying amount of the reportable segment’s goodwill over the implied fair value of the goodwill.
Other Investments
Other Investments

Investments in which the Company does not have the ability to exercise significant influence and does not have readily determinable fair values, are recorded at cost minus impairment, plus or minus changes from observable price changes in orderly transactions for identical or similar investments of the same issuer, in accordance with the measurement alternative described in Accounting Standards Codification (“ASC”) 321, Investments–Equity Securities. See Note 4—Balance Sheet Components for further information.

As part of the Company’s policy to maximize return on strategic investment opportunities, while preserving capital and limiting downside risk, the Company may at times enter into equity investments or simple agreements for future equity. The nature and timing of the Company’s investments will depend on available capital at any particular time and the investment opportunities identified and available to the Company. However, the Company generally does not make investments for speculative purposes and does not intend to engage in the business of making other investments.
Leases
Leases

The Company has lease arrangements for its offices and facilities. The Company determines if an arrangement is a lease at inception by evaluating whether the arrangement conveys the right-of-use (“ROU”) to an identified asset and whether the Company obtains substantially all of the economic benefits from and has the ability to direct the use of the asset. Leases are recorded as an operating lease right-of-use assets and operating lease liabilities on the consolidated balance sheets. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets.

Lease 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. Lease ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the expected lease term, including options to extend the lease when it is reasonably certain that the Company will exercise that option. The Company uses the discount rate implicit in the lease unless that rate cannot be readily determined. In that case, the Company uses its incremental borrowing rate, which is the rate of interest that the Company would have to pay to borrow on a collateralized basis an amount equal to the lease payments over the expected lease term. Lease ROU assets consist of the initial measurement of lease liabilities, any lease payments made to lessor on or before the lease commencement date, adjusted for any lease incentives received, and any initial direct costs incurred by the Company.
Operating lease expense for lease payments is recognized on a straight-line basis over the expected lease term.
Fair Value Measurements
Fair Value Measurements

The authoritative guidance with respect to fair value established a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels and requires that assets and liabilities carried at fair value be classified and disclosed in one of three categories, as presented below. There were no transfers in and out of Levels 1 and 2, and activity in Level 3 fair value measurements.

Financial instruments measured at fair value on a recurring basis were based upon a three-tier hierarchy as follows:

Level 1: Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities and investments in U.S. treasury securities and money market funds.
Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, as corroborated by market data.

Level 3: Unobservable inputs in which little or no market data exists, therefore developed using management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date.

The Company determines the level in the fair value hierarchy within which each fair value measurement falls in its entirety, based on the lowest level input that is significant to the fair value measurement in its entirety. In determining the appropriate levels, the Company performs an analysis of the assets and liabilities at each reporting period end.
The Company’s cash and cash equivalents, prepaid and other current assets, accounts payable, and accrued expenses and other approximate their fair value due to the short-term nature of these assets and liabilities. The Company’s marketable debt securities are classified as Level 1 or Level 2 assets. See Note 6—Financial Instruments for further information.
Research and Development and Cost-Share Projects
Research and Development

Research and development represent costs incurred to develop the Company’s technologies. These costs consist of personnel costs, including salaries, employee benefit costs, bonuses and stock-based compensation expenses, software costs, computing costs, hardware and experimental supplies and prototyping, and expenses for outside engineering contractors for analytical work and consulting costs, as well as depreciation and amortization expense for capitalized assets associated with these functions. The Company expenses all research and development costs in the periods in which they are incurred.
Cost-Share Projects

The Company has certain cost-share reimbursable projects for several research and development (“R&D”) projects related to nuclear recycling technologies awarded by the DOE’s Advanced Research Projects Agency-Energy (“ARPA-E”) (the “cost-share projects”) where the Company elected to record the reimbursements on a net presentation basis based on the period in which the expense was incurred and reimbursable under the guidelines of the cost-share projects on the consolidated statements of operations. Additionally, reimbursable R&D expenses for equipment purchased under the guidelines of the cost-share projects are offset to the cost basis of the equipment, resulting in no carrying value for the property, plant and equipment on the consolidated balance sheets and no reported cash flows. In the event the equipment is sold upon completion of the cost-share projects, the Company may be obligated to reimburse the DOE in the event the proceeds are in excess of $5 per asset, which at such time, if applicable, will be reported on a net presentation basis with no gain recognized and no cash flows.
General and Administrative
General and Administrative

General and administrative expenses consist primarily of payroll and other personnel-related costs, including stock-based compensation expense, for the Company’s employees involved in general corporate functions including finance, legal, procurement, and human resources, rent and other occupancy expenses, professional fees for legal and accounting, travel costs, promotional expenses, as well as depreciation and amortization expense for capitalized assets associated with these functions.
Stock-Based Compensation
Stock-Based Compensation
The Company accounts for stock-based compensation by measuring and recognizing expense for all stock-based awards made to employees and non-employees based on the estimated grant-date fair values for all stock-based compensation arrangements. The Company recognizes stock-based compensation over each recipient’s requisite service period, which is generally the vesting period. The Company has elected to recognize actual forfeitures by reducing the stock-based compensation in the same period as the forfeitures occur. The Company estimates the fair value of stock options granted to employees and non-employees using the Black-Scholes option pricing model. The Black-Scholes option pricing model requires the input of subjective assumptions, including the Legacy Oklo’s common stock fair value and the Company’s common stock fair value, expected volatility, expected dividend yield, risk-free rate of return, and the expected term. The Company classifies stock-based compensation costs in the same manner in which the award recipient’s cash compensation cost is classified on the consolidated statements of operations. See Note 10—Stock-based Compensation for further information.
Income Taxes
Income Taxes

Because the Company has not generated revenue from the sale of power from its powerhouses or sales of radioisotopes and is anticipated to remain as such for the next several years, income taxes have been minimal to date. The Company follows the asset and liability method of accounting for income taxes under ASC 740, Income Taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that included the enactment date. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized.

ASC 740 prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. The Company is currently not aware of any issues under review that could result in significant payments, accruals, or material deviation from its position.
Recently Adopted Accounting Standards and Recently Issued and Not Adopted Accounting Standards
Recently Adopted Accounting Standards

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances the transparency and decision usefulness of income tax disclosures. The amendments, among other items, require (i) additional disaggregation of income taxes paid by jurisdiction, (ii) enhanced effective tax rate reconciliation disclosures with specified categories and further disaggregation when quantitative thresholds are met, and (iii) incremental disclosures about income taxes in certain circumstances. The Company is adopting ASU 2023-09 in its annual financial statements in the current year ended December 31, 2025. The Company is applying the amendments retrospectively to all periods presented upon adoption. The amendments primarily impact disclosures and do not have a material impact on the Company’s consolidated financial position, results of operations, or cash flows.

Recently Issued and Not Adopted Accounting Standards

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which will require disaggregated disclosures in the notes to the financial statements of certain categories of expenses, including purchases of inventory, employee compensation, and depreciation and amortization, that are included in expense line items within the statement of operations. ASU 2024-03 will be applied prospectively; however, retrospective application is permitted. ASU 2024-03, as clarified in ASU 2025-01, Clarifying the Effective Date, requires public business entities to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is evaluating the impact of ASU 2024-03 on its disclosures in the notes to its financial statements.

In September 2025, the FASB issued ASU 2025‑06, Intangibles—Goodwill and Other—Internal‑Use Software (Subtopic 350‑40): Targeted Improvements to the Accounting for Internal‑Use Software, which updates the guidance for capitalization of internal‑use software costs, including clarifications to the criteria for capitalizing configuration, development, and implementation activities. ASU 2025-06 is effective for the Company beginning with interim reporting for fiscal year 2029. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2025-06 on its accounting policies and related disclosures.

In December 2025, the FASB issued ASU 2025‑10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which provides updated guidance on how to recognize, measure, and present government grants. ASU 2025‑10 is effective for the Company for annual periods beginning after December 15, 2028, including interim periods within those periods using a modified prospective, modified retrospective, or full retrospective transition
approach. Early adoption is permitted. The Company is currently assessing the effect of ASU 2025-10 on its financial statements.

Management does not believe that any other recently issued, but not yet effective, authoritative guidance, if currently adopted, would have a material impact on the Company’s financial statement presentation or disclosures.
Reclassifications
Reclassifications

Certain prior year amounts have been reclassified to conform to current period presentation. These reclassifications were immaterial, both individually and in aggregate. These changes did not impact previously reported loss from operations or net loss.
v3.26.1
Business Combination (Tables)
 12 Months Ended
Dec. 31, 2025
Business Combination [Abstract]  
Schedule of Business Acquisitions, by Acquisition
The composition of the purchase price is as follows:

Cash$1,016 
Common stock27,408 
Total purchase consideration$28,424 
Schedule of Assets Acquired and Liabilities Assumed
The purchase price allocation resulted in the following amounts being allocated to the assets acquired and liabilities assumed at the Acquisition Date based upon their respective fair values as summarized below:
Cash$116 
Prepaid expenses99 
Property and equipment40 
Operating lease right-of-use assets19 
Indefinite-lived intangible assets27,500 
Goodwill6,621 
Operating lease liability(19)
Other current liabilities(268)
Deferred tax liabilities(5,684)
Net assets acquired
$28,424 
v3.26.1
Balance Sheet Components (Tables)
 12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Schedule of Prepaid and Other Current Assets
Prepaid and other current assets are summarized as follows:
As of December 31,
20252024
Prepaid expense$18,853 $2,119 
Accrued interest receivable4,976 1,138 
Other1,969 868 
Total prepaid and other current assets$25,798 $4,125 
Schedule of Property, Plant and Equipment, Net
Property, plant and equipment, net are summarized as follows:
As of December 31,
Estimated Useful Lives (Years)20252024
Computers and equipment
3 - 7
$366 $366 
Furniture, fixtures and machinery7483 146 
Software31,405 1,020 
Leasehold improvements*62 45 
LandN/A5,145 — 
Total property and equipment, gross7,461 1,577 
Less: Accumulated depreciation and amortization(897)(375)
Construction in progress and equipment deposits35,748 — 
Total property, plant and equipment, net$42,312 $1,202 
* Shorter of lease term or estimated useful life of the asset.
Schedule of Other Assets
Other assets are summarized as follows:
As of December 31,
20252024
Other$217 $140 
Other investments12,086 — 
Total other assets$12,303 $140 
Schedule of Accrued Expenses and Other
Accrued expenses and other are summarized as follows:
As of December 31,
20252024
Accrued professional fees$1,838 $652 
Accrued payroll and bonuses10,998 636 
General accrued expenses7,210 134 
Other current liabilities451 463 
Total accrued expenses and other$20,497 $1,885 
v3.26.1
Leases (Tables)
 12 Months Ended
Dec. 31, 2025
Leases [Abstract]  
Schedule of Lease Supplemental Information and Lease Cost
The table below presents supplemental information related to the operating leases:
Years Ended December 31,
20252024
Cash payments included in the measurement of operating lease liabilities during the year$862$289
Operating lease liabilities arising from obtaining lease right-of-use assets during the year$1,143$1,185
Weighted-average remaining lease term (in months) as of year-end2924
Weighted-average discount rate during the year8.91 %8.76 %
The components of operating lease costs were as follows:
Years Ended December 31,
20252024
Operating lease costs included in:
Research and development$841 $234 
General and administrative321 87 
Total operating costs (1)$1,162 $321 

(1) Month-to-month lease arrangements for the years ended December 31, 2025 and 2024 of $276 and $184, respectively, are included in the captions within operating lease costs.
Schedule of Operating Lease Maturities
As of December 31, 2025, future maturities of the operating lease liabilities were as follows :
2026$990 
2027203 
2028191 
2029199 
203034 
Minimum lease payments1,617 
Less imputed interest(167)
Present value of operating lease liabilities$1,450 
Current portion of operating lease liabilities$904 
Noncurrent portion of operating lease liabilities546 
Total operating lease liabilities$1,450 
v3.26.1
Financial Instruments (Tables)
 12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Schedule of Cash, Cash Equivalents and Marketable Debt Securities by Significant Investment Category
The following tables show the Company’s cash, cash equivalents, and marketable debt securities by significant investment category:

As of December 31, 2025
Amortized CostUnrealized GainsFair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $11,022 $— $— 
Level 1:
Money market funds— — — 777,423 — — 
U.S. Treasury securities504,008 1,123 505,131 — 320,563 184,568 
Subtotal504,008 1,123 505,131 777,423 320,563 184,568 
Level 2 (1):
Commercial paper118,907 56 118,963 — 118,963 — 
Total $622,915 $1,179 $624,094 $788,445 $439,526 $184,568 

(1) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.

As of December 31, 2025, interest receivables related to available-for-sale marketable debt securities of $4,005 were included in marketable debt securities on the consolidated balance sheets.
As of December 31, 2024
Amortized Cost
Unrealized Gains
Unrealized Losses (1)
Fair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $— $3,020 $— $— 
Level 1:
Money market funds— — — — 94,112 — — 
U.S. Treasury securities156,040 1,688 (6)157,722 — 110,249 47,473 
Subtotal156,040 1,688 (6)157,722 94,112 110,249 47,473 
Level 2 (2):
Commercial paper19,902 531 — 20,433 — 20,433 — 
Total $175,942 $2,219 $(6)$178,155 $97,132 $130,682 $47,473 

(1) There was no allowance for expected credit losses on available-for-sale marketable debt securities as of December 31, 2024 as the unrealized losses were deemed to be temporary in nature.

(2) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.
Schedule of Fair Value of the Company’s Marketable Debt Securities, by Contractual Maturity
The following table shows the fair value of the Company’s marketable debt securities, by contractual maturity, as of December 31, 2025:

Due within 1 year$439,526 
Due after 1 year through 5 years184,568 
Total fair value$624,094 
v3.26.1
Stock-based Compensation (Tables)
 12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions
Compensation costs was estimated for stock options based on the grant date fair value using a Black-Scholes option valuation model, consistent with authoritative guidance utilizing the following assumptions for the year ended December 31, 2024:

Expected volatility79.67 %
Expected dividend yield0 %
Risk-free interest rate4.08 %
Expected term6.3 years
Schedule of Options Activity
A summary of the stock option award activity during the year ended December 31, 2025 is as follows:

Number of SharesWeighted-Average Exercise PriceWeighted-Average Remaining Contractual Life (in years)
Common stock awards outstanding at January 1, 20259,470,382$1.95 7.91
Exercised(2,759,216)1.46 
Forfeited(242,726)3.22 
Common stock awards outstanding at December 31, 20256,468,4402.11 7.25
Common stock awards exercisable at December 31, 20252,508,6681.65 6.76
Common stock awards not vested at December 31, 20253,959,772
Schedule of Restricted Stock Unit Award Activity
A summary of restricted stock unit award activity during the year ended December 31, 2025 is as follows:

Number of Units
Weighted-Average Grant Date Fair Value
 
Unvested
Vested
Restricted stock units outstanding at January 1, 20251,252,166 134,832 $8.02
Granted2,081,611— 53.51
Vested
(870,821)870,821 26.07
Issued— (571,741)—
Forfeited(39,478)— 15.95
Restricted stock units outstanding at December 31, 20252,423,478433,912 37.84
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity
A summary of unvested restricted stock award activity during the year ended December 31, 2025 is as follows:
​
Unvested Number of UnitsWeighted Average Grant Date Fair Value
Restricted stock awards outstanding at January 1, 2025—$— 
Granted274,33933.39 
Restricted stock awards outstanding at December 31, 2025274,33933.39
Schedule of Stock-Based Compensation Cost
Stock-based compensation costs charged to operations is summarized as follows:
Years Ended December 31,
20252024
Research and development$12,251 $7,797 
General and administrative29,544 4,687 
Total costs charged to operations$41,795 $12,484 
Schedule of Unrecognized Compensation Expense
Unrecognized stock-based compensation costs and expected weighted-average period to be recognized related to the stock-based compensation awards as of December 31, 2025 is presented below:

Restricted StockStock OptionsTotals
Unrecognized stock-based compensation cost$96,989 $14,933 $111,922 
Weighted-average period over which cost is expected to be recognized (in years)3.443.553.46
v3.26.1
Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Schedule of Income Taxes Provision
The components of income tax (benefit) expense consist of the following:

As of December 31,
Current tax expense:
2025
2024
Federal$— $— 
State and local— 683 
Total current tax expense— 683 
Deferred tax benefit:
Federal(3,516)— 
State and local(1,013)— 
Total deferred tax benefit(4,529)— 
Total income tax (benefit) expense$(4,529)$683 
Schedule of Deferred Taxes
Significant components of the Company’s deferred taxes are as follows:
As of December 31,
20252024
Deferred tax assets:
Net operating loss carryforwards $5,599 $3,078 
R&D tax credit10,692 2,443 
Capitalized R&D expenses16,039 5,617 
Capitalized start-up expenses34,210 15,628 
Advance payment5,267 — 
Operating lease liabilities305 216 
Stock-based compensation2,598 394 
Other15 73 
Accrued expenses2,079 — 
Deferred tax assets76,804 27,449 
Valuation allowance(71,625)(26,775)
Total deferred tax assets5,179 674 
Deferred tax liabilities:
Indefinite-lived intangible assets(5,794)— 
Right-of-use assets(292)(207)
Unrealized gain on marketable debt securities(248)(467)
Total deferred tax liabilities(6,334)(674)
Net deferred tax liabilities$(1,155)$— 
Schedule of Effective Income Tax Rate Reconciliation
The benefit for income taxes differs from the amount obtained by applying the federal statutory income tax rate as follows:

Years Ended December 31,
20252024
AmountPercentAmountPercent
U.S. federal statutory tax rate $(23,140)21.0 %$(15,316)21.0 %
State and local taxes, net of federal benefit (a)
(1,013)0.9 %539 (0.7)%
Effect of change in tax laws or rates enacted in current period— — %— — %
Tax credits
R&D tax credits(9,359)8.5 %(1,290)1.8 %
Change in valuation allowances43,952 (39.9)%16,011 (21.3)%
Nontaxable and nondeductible items
Nondeductible executive compensation10,275 (9.3)%242 (0.3)%
Change in fair value of simple agreements for future equity— — %5,852 (8.0)%
Transaction costs— — %(1,555)2.1 %
Interest expense— — %(1,190)1.6 %
Stock-based compensation(26,750)24.3 %(2,981)4.1 %
Other342 (0.3)%100 (0.8)%
Changes in unrecognized tax benefits1,164 (1.1)%271 (0.4)%
Effective tax rate$(4,529)4.1 %$683 (0.9)%
(a) State taxes in Idaho and California made up the majority (greater than 50 percent) of the tax effect in this category for the tax years ended December 31, 2025 and 2024, respectively.
Schedule of Valuation Allowance
The following table represents a roll forward of the qualifying accounts consisting of the valuation allowance for deferred tax assets:

Years Ended December 31,
20252024
Valuation allowance for deferred tax assets - beginning of year$26,775 $11,184 
Change in valuation allowance recognized in the provision for federal income taxes for the year43,952 16,011
Change in valuation allowance recognized in provision for state and local income taxes for during the year679 47 
Change in valuation allowance recognized to other accounts219 (467)
Valuation allowance for deferred tax assets - end of year$71,625 $26,775 
Schedule of Unrecognized Tax Benefits A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
Years Ended December 31,
20252024
Balance at beginning of year$271 $— 
Additions for tax positions taken in prior year228 142 
Additions for tax positions related to the current year936 129
Balance at end of year$1,435 $271 
Schedule of Income Taxes Paid
Income taxes paid consisted of the following:
Years Ended December 31,
20252024
Federal$ * $223 
California2,464 550 
New York City*123 
Other*11 
Total$2,464 $907 
* Represents jurisdictions below for the threshold for the years presented.
v3.26.1
Nature of Operations and Organization (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
USD ($)
MWd
Dec. 31, 2024
USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Powerhouse production capability, nuclear fuel | MWd 15  
Powerhouse production capability, fresh fuel | MWd 75  
Powerhouse useful life 30 years  
Cash, cash equivalents, and marketable securities $ 1,412,539  
Net loss 105,663 $ 73,616
Operating loss 139,294 52,801
Net cash used in operating activities 82,174 38,390
Accumulated deficit $ 240,772 $ 135,109
v3.26.1
Summary of Significant Accounting Policies - Narrative (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
segment
shares
Dec. 31, 2024
USD ($)
segment
shares
Property, Plant and Equipment [Line Items]    
Number of operating segments | segment 1  
Number of reportable segments | segment 1 1
Threshold per asset | $   $ 5
Stock Options    
Property, Plant and Equipment [Line Items]    
Antidilutive securities excluded from earnings per share (in shares) 6,468,440 9,470,382
Restricted Stock    
Property, Plant and Equipment [Line Items]    
Antidilutive securities excluded from earnings per share (in shares) 640,125 0
Restricted Stock    
Property, Plant and Equipment [Line Items]    
Antidilutive securities excluded from earnings per share (in shares) 2,423,478 1,252,166
v3.26.1
Business Combination - Narrative (Details)
 3 Months Ended 12 Months Ended
Feb. 28, 2025
USD ($)
project
$ / shares
shares
May 09, 2024
shares
Dec. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
shares
Dec. 31, 2024
USD ($)
shares
Business Combination [Line Items]          
Payment for acquisition of business, net of cash acquired       $ 900,000 $ 0
Revenue of acquiree since acquisition date       0  
Loss from operations since acquisition date       $ 0  
Issuance of stock (in shares) | shares   43,099,811   2,759,216 2,256,157
Stock issued during period, value       $ 4,028,000 $ 1,044,000
AltC Shares          
Business Combination [Line Items]          
Stock issued during period, value         $ 258,955,000
AltC Founder Shares          
Business Combination [Line Items]          
Issuance of stock (in shares) | shares   12,500,000      
AltC Private Placement Shares          
Business Combination [Line Items]          
Issuance of stock (in shares) | shares   1,450,000      
AltC Public Stockholders          
Business Combination [Line Items]          
Issuance of stock (in shares) | shares   29,149,811      
SAFEs          
Business Combination [Line Items]          
Stock issued during period, shares, conversion of convertible securities (in shares) | shares         8,407,894
Stock issued during period, conversion of convertible securities         $ 84,138,000
Atomic Alchemy, Inc.          
Business Combination [Line Items]          
Total purchase consideration $ 28,424,000        
Payment for acquisition of business, net of cash acquired $ 900,000        
Share price (in dollars per share) | $ / shares $ 33.39        
Business combination, consideration transferred, equity $ 27,408,000        
Transaction costs $ 410,000        
Decrease in deferred tax liabilities     $ 99,000    
IPR&D projects, number | project 2        
Indefinite-lived intangible assets $ 27,500,000        
Tax-deductible goodwill 0        
Atomic Alchemy, Inc. | In Process Research and Development, Abundantia Project          
Business Combination [Line Items]          
Indefinite-lived intangible assets 4,600,000        
Atomic Alchemy, Inc. | In Process Research and Development, Meitner Project          
Business Combination [Line Items]          
Indefinite-lived intangible assets $ 22,900,000        
Atomic Alchemy, Inc. | Class A common stock, stock purchase consideration          
Business Combination [Line Items]          
Equity interests issued or issuable (in shares) | shares 820,840        
Atomic Alchemy, Inc. | Class A common stock, post combination services consideration          
Business Combination [Line Items]          
Equity interests issued or issuable (in shares) | shares 274,339        
v3.26.1
Business Combination - Schedule of Purchase Price (Details) - Atomic Alchemy, Inc.
$ in Thousands
Feb. 28, 2025
USD ($)
Business Combination [Line Items]  
Cash $ 1,016
Common stock 27,408
Total purchase consideration $ 28,424
v3.26.1
Business Combination - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Feb. 28, 2025
Dec. 31, 2024
Business Combination [Line Items]      
Goodwill $ 6,621   $ 0
Atomic Alchemy, Inc.      
Business Combination [Line Items]      
Cash   $ 116  
Prepaid expenses   99  
Property and equipment   40  
Operating lease right-of-use assets   19  
Indefinite-lived intangible assets   27,500  
Goodwill   6,621  
Operating lease liability   (19)  
Other current liabilities   (268)  
Deferred tax liabilities   (5,684)  
Net assets acquired   $ 28,424  
v3.26.1
Balance Sheet Components - Schedule of Prepaid and Other Current Assets (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Prepaid expense $ 18,853 $ 2,119
Accrued interest receivable 4,976 1,138
Other 1,969 868
Total prepaid and other current assets $ 25,798 $ 4,125
v3.26.1
Balance Sheet Components - Schedule of Property, Plant and Equipment, net (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 7,461 $ 1,577
Less: Accumulated depreciation and amortization (897) (375)
Construction in progress and equipment deposits 35,748 0
Total property, plant and equipment, net 42,312 1,202
Computers and equipment    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 366 366
Computers and equipment | Maximum    
Property, Plant and Equipment [Line Items]    
Property, Plant and Equipment, Useful Life 7 years  
Computers and equipment | Minimum    
Property, Plant and Equipment [Line Items]    
Property, Plant and Equipment, Useful Life 3 years  
Furniture, fixtures and machinery    
Property, Plant and Equipment [Line Items]    
Property, Plant and Equipment, Useful Life 7 years  
Total property and equipment, gross $ 483 146
Software    
Property, Plant and Equipment [Line Items]    
Property, Plant and Equipment, Useful Life 3 years  
Total property and equipment, gross $ 1,405 1,020
Leasehold improvements    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross 62 45
Land    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 5,145 $ 0
v3.26.1
Balance Sheet Components - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Depreciation and amortization $ 522 $ 268
v3.26.1
Balance Sheet Components - Schedule of Other Assets (Details) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Other $ 217,000 $ 140,000
Other investments 12,086,000 0
Total other assets $ 12,303,000 $ 140,000
v3.26.1
Balance Sheet Components - Schedule of Accrued Expenses and Other (Details) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Accrued professional fees $ 1,838,000 $ 652,000
Accrued payroll and bonuses 10,998,000 636,000
General accrued expenses 7,210,000 134,000
Other current liabilities 451,000 463,000
Total accrued expenses and other $ 20,497,000 $ 1,885,000
v3.26.1
Leases - Supplemental Information (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Leases [Abstract]    
Cash payments included in the measurement of operating lease liabilities during the year $ 862 $ 289
Operating lease liabilities arising from obtaining lease right-of-use assets during the year $ 1,143 $ 1,185
Weighted-average remaining lease term (in months) as of year-end 29 months 24 months
Weighted-average discount rate during the year 8.91% 8.76%
v3.26.1
Leases - Components of Operating Lease Costs (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Lessee, Lease, Description [Line Items]    
Total operating lease costs $ 1,162 $ 321
Month-to-Month Lease Arrangements    
Lessee, Lease, Description [Line Items]    
Total operating lease costs 276 184
Research and development    
Lessee, Lease, Description [Line Items]    
Total operating lease costs 841 234
General and administrative    
Lessee, Lease, Description [Line Items]    
Total operating lease costs $ 321 $ 87
v3.26.1
Leases - Maturities Of Operating Lease Liabilities (Details) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Leases [Abstract]    
2026 $ 990,000  
2027 203,000  
2028 191,000  
2029 199,000  
2030 34,000  
Minimum lease payments 1,617,000  
Less imputed interest (167,000)  
Current portion of operating lease liabilities 904,000 $ 481,000
Noncurrent portion of operating lease liabilities 546,000 $ 543,000
Total operating lease liabilities $ 1,450,000  
v3.26.1
Financial Instruments - Cash, Cash Equivalents, and Marketable Securities by Investment Category (Details) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash $ 11,022,000 $ 3,020,000
Amortized Cost 622,915,000 175,942,000
Unrealized Gains 1,179,000 2,219,000
Unrealized Losses   (6,000)
Fair Value 624,094,000 178,155,000
Cash and Cash Equivalents 788,445,000 97,132,000
Current Marketable Debt Securities 439,526,000 130,682,000
Noncurrent Marketable Debt Securities 184,568,000 47,473,000
Allowance for credit loss   0
Fair Value, Inputs, Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost 504,008,000 156,040,000
Unrealized Gains 1,123,000 1,688,000
Unrealized Losses   (6,000)
Fair Value 505,131,000 157,722,000
Cash and Cash Equivalents 777,423,000 94,112,000
Current Marketable Debt Securities 320,563,000 110,249,000
Noncurrent Marketable Debt Securities 184,568,000 47,473,000
Fair Value, Inputs, Level 1 | U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost 504,008,000 156,040,000
Unrealized Gains 1,123,000 1,688,000
Unrealized Losses   (6,000)
Fair Value 505,131,000 157,722,000
Current Marketable Debt Securities 320,563,000 110,249,000
Noncurrent Marketable Debt Securities 184,568,000 47,473,000
Fair Value, Inputs, Level 1 | Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and Cash Equivalents 777,423,000 94,112,000
Fair Value, Inputs, Level 2 | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost 118,907,000 19,902,000
Unrealized Gains 56,000 531,000
Fair Value 118,963,000 20,433,000
Current Marketable Debt Securities $ 118,963,000 $ 20,433,000
v3.26.1
Financial Instruments - Narrative (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]    
Debt securities interest receivable   $ 826
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]   Prepaid and other current assets
Prepaid Expenses and Other Current Assets    
Debt Securities, Available-for-Sale [Line Items]    
Debt securities interest receivable $ 3,160  
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Prepaid and other current assets  
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Current    
Debt Securities, Available-for-Sale [Line Items]    
Debt securities interest receivable $ 4,005  
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Marketable debt securities  
v3.26.1
Financial Instruments - Fair Value of Marketable Securities by Contractual Maturities (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]    
Due within 1 year $ 439,526  
Due after 1 year through 5 years 184,568  
Fair Value $ 624,094 $ 178,155
v3.26.1
Simple Agreements for Future Equity (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]    
Proceeds from simple agreements for future equity $ 0 $ 10,232,000
Fair Value, Inputs, Level 3    
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]    
SAFE notes, change in fair value of shares   $ 27,864,000
v3.26.1
Right of First Refusal Liability (Details) - USD ($)
$ in Thousands
 1 Months Ended
Mar. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Feb. 16, 2024
Commitments and Contingencies Disclosure [Abstract]        
Commitment period       20 years
Purchase power agreement additional extension term       20 years
Right of first refusal term       36 months
Right of first refusal payment $ 25,000      
Right of first refusal liability   $ 25,000 $ 25,000  
v3.26.1
Stockholders’ Equity (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 8 Months Ended 12 Months Ended
Dec. 04, 2025
USD ($)
Sep. 11, 2025
USD ($)
$ / shares
shares
Sep. 03, 2025
USD ($)
Jun. 16, 2025
USD ($)
$ / shares
shares
Jun. 13, 2025
shares
Jun. 02, 2025
USD ($)
May 09, 2024
director
vote
shares
Dec. 31, 2025
USD ($)
$ / shares
shares
Aug. 27, 2025
USD ($)
$ / shares
shares
Sep. 03, 2025
USD ($)
Dec. 31, 2024
$ / shares
shares
Dec. 31, 2025
USD ($)
$ / shares
shares
Dec. 31, 2024
USD ($)
$ / shares
shares
Class of Stock [Line Items]                          
Common stock and preferred stock, authorized (in shares)               501,000,000       501,000,000  
Common stock, authorized (in shares)               500,000,000     500,000,000 500,000,000 500,000,000
Common stock, par value (in dollars per share) | $ / shares               $ 0.0001     $ 0.0001 $ 0.0001 $ 0.0001
Preferred stock, authorized               1,000,000       1,000,000  
Preferred stock, par value (in dollars per share) | $ / shares               $ 0.0001       $ 0.0001  
Common stock, voting rights per share | vote             1            
Number of directors | director             7            
Issuance of stock (in shares)             43,099,811         2,759,216 2,256,157
Proceeds from sale of common stock, net of offering costs | $                       $ 1,263,599 $ 0
Issuance of common stock | $                       4,028 1,044
Stock issuance costs | $                       $ 2,814 11,058
Common stock withheld for taxes (in shares)                       67,187  
Payment of taxes from common stock withheld | $                       $ 1,647 $ 0
Underwritten Public Offering                          
Class of Stock [Line Items]                          
Proceeds from issuance of common stock, gross | $       $ 460,000                  
Issuance of stock (in shares)       7,666,667                  
Offering price per share (in dollars per share) | $ / shares       $ 60.00                  
Proceeds from sale of common stock, net of offering costs | $       $ 441,600                  
Payments for underwriting expense | $       18,400                  
Other offering costs | $       1,498                  
Issuance of common stock | $       $ 440,102               440,102  
Over allotment option                          
Class of Stock [Line Items]                          
Issuance of stock (in shares)       6,666,667 1,000,000                
Over-allotment option period         30 days                
At The Market Offering                          
Class of Stock [Line Items]                          
Proceeds from issuance of common stock, gross | $ $ 1,500,000 $ 139,999 $ 139,999     $ 400,000   $ 300,000 $ 400,000 $ 539,999   821,999  
Proceeds from sale of common stock, net of offering costs | $                       820,364  
Issuance of common stock | $                       $ 820,364  
Sale of stock, commission percentage           0.025   0.015          
Number of shares issued and offered (in shares)   1,925,066           3,397,872 5,458,953     10,781,891  
Legacy Oklo price per share upon conversion (in dollars per share) | $ / shares   $ 72.72           $ 88.29 $ 73.27     $ 88.29  
Payment of sales agent commissions | $                       $ 18,000  
Stock issuance costs | $                       $ 1,635  
Employee Stock                          
Class of Stock [Line Items]                          
Reserved for future issuance (in shares)               2,441,926       2,441,926  
Restricted Stock                          
Class of Stock [Line Items]                          
Vesting of restricted stock units (in shares)                       571,741  
Earnout Shares                          
Class of Stock [Line Items]                          
Reveres recapitalization, shares issued (in shares)                     14,699,794    
Earnout Shares, Vested Options                          
Class of Stock [Line Items]                          
Reveres recapitalization, shares issued (in shares)                     433,348    
Legacy Oklo 2016 Plan                          
Class of Stock [Line Items]                          
Reserved for future issuance (in shares)               6,468,440       6,468,440  
2024 Plan                          
Class of Stock [Line Items]                          
Reserved for future issuance (in shares)               12,805,133       12,805,133  
Common Class A                          
Class of Stock [Line Items]                          
Common stock, authorized (in shares)               500,000,000       500,000,000  
Common stock, par value (in dollars per share) | $ / shares               $ 0.0001       $ 0.0001  
v3.26.1
Stock-based Compensation - Narrative (Details)
 12 Months Ended
Apr. 01, 2025
USD ($)
May 09, 2024
USD ($)
Dec. 31, 2025
USD ($)
formerEmployee
$ / shares
shares
Dec. 31, 2024
USD ($)
$ / shares
shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Options, outstanding (in shares)     6,468,440 9,470,382
Fair value of options granted during the period | $       $ 1,108,000
Grant date intrinsic value (in dollars per share) | $ / shares       $ 3.15
Proceeds from simple agreements for future equity | $     $ 0 $ 10,232,000
Granted (in shares)     0  
Options exercised in period, intrinsic value | $     $ 188,386,000 28,537,000
Options vested in period, fair value | $     4,183,000 $ 2,916,000
Options exercisable, intrinsic value | $     175,873,000  
Options, vested and expected to vest, exercisable, aggregate intrinsic value | $     $ 450,533,000  
Share price (in dollars per share) | $ / shares     $ 71.76  
Plan modification, incremental cost | $ $ 10,234,000 $ 7,784,000    
Number of employees, vested during termination events | formerEmployee     2  
Number of employees with extension of post-termination exercise period | formerEmployee     1  
Restricted Stock        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Plan modification, incremental cost | $     $ 4,765,000  
Vested in period, aggregate intrinsic value | $     $ 22,705,000  
Employee Stock        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Award expiration period     20 years  
Granted (in shares)     0  
Reserved for future issuance (in shares)     2,441,926  
Stock Options        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Award vesting period 5 years      
RSU and Options        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Plan modification, incremental cost | $     $ 10,832,000  
Legacy Oklo 2016 Plan        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Award vesting rate (as a percent)     20.00%  
Award vesting period     5 years  
Award vesting commencement period     1 year  
Award expiration period     10 years  
Options, outstanding (in shares)     6,468,440  
Reserved for future issuance (in shares)     6,468,440  
The 2024 Plan        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Award expiration period     10 years  
Reserved for future issuance (in shares)     12,805,133  
Restricted stock units were outstanding (in shares)     2,857,390  
The 2024 Plan | Restricted Stock        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Restricted stock units were outstanding (in shares)     2,857,390  
Vested (in shares)     433,912  
Nonvested (in shares)     2,423,478  
v3.26.1
Stock-based Compensation - Schedule of Fair Value of Stock Options Assumptions (Details) - Stock Options
 12 Months Ended
Dec. 31, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Expected volatility 79.67%
Expected dividend yield 0.00%
Risk-free interest rate 4.08%
Expected term 6 years 3 months 18 days
v3.26.1
Stock-based Compensation - Stock Option Award Activity (Details) - $ / shares
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Number of Shares    
Stock option awards outstanding, beginning balance (in shares) 9,470,382  
Exercised (in shares) (2,759,216)  
Forfeited (in shares) (242,726)  
Stock option awards outstanding, ending balance (in shares) 6,468,440 9,470,382
Stock option awards exercisable (in shares) 2,508,668  
Stock option awards not vested (in shares) 3,959,772  
Weighted-Average Exercise Price    
Stock option awards outstanding, beginning balance (in dollars per share) $ 1.95  
Exercised (in dollars per share) 1.46  
Forfeited (in dollars per share) 3.22  
Stock option awards outstanding, ending balance (in dollars per share) 2.11 $ 1.95
Stock option awards exercisable (in dollars per share) $ 1.65  
Weighted-Average Remaining Contractual Life (in years)    
Stock option awards outstanding, weighted average remaining contractual life 7 years 3 months 7 years 10 months 28 days
Stock option awards exercisable, weighted average remaining contractual life 6 years 9 months 3 days  
v3.26.1
Stock-based Compensation - Schedule of Restricted Stock Unit Awards Activity (Details) - Restricted Stock
 12 Months Ended
Dec. 31, 2025
$ / shares
shares
Weighted-Average Grant Date Fair Value  
Beginning balance (in dollars per share) | $ / shares $ 8.02
Granted (in dollars per share) | $ / shares 53.51
Vested (in dollars per share) | $ / shares 26.07
Forfeited (in dollars per share) | $ / shares 15.95
Ending balance (in dollars per share) | $ / shares $ 37.84
Unvested  
Number of Units  
Beginning balance (in shares) 1,252,166
Granted (in shares) 2,081,611
Vested (in shares) 870,821
Forfeited (in shares) (39,478)
Ending balance (in shares) 2,423,478
Vested  
Number of Units  
Beginning balance (in shares) 134,832
Vested (in shares) 870,821
Issued (in shares) (571,741)
Ending balance (in shares) 433,912
Beginning balance (in shares) 0
Granted (in shares) 274,339
Ending balance (in shares) 274,339
Weighted-Average Grant Date Fair Value  
Beginning balance (in dollars per share) | $ / shares $ 0
Granted (in dollars per share) | $ / shares 33.39
Ending balance (in dollars per share) | $ / shares $ 33.39
v3.26.1
Stock-Based Compensation - Schedule of Stock-Based Compensation Cost (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Total costs charged to operations $ 41,795 $ 12,484
Research and development    
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Total costs charged to operations 12,251 7,797
General and administrative    
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Total costs charged to operations $ 29,544 $ 4,687
v3.26.1
Stock-based Compensation - Schedule of Unrecognized Compensation Expense (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
USD ($)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]  
Unrecognized stock-based compensation cost $ 111,922
Weighted-average period over which cost is expected to be recognized (in years) 3 years 5 months 15 days
Restricted Stock  
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]  
Unrecognized stock-based compensation cost $ 96,989
Weighted-average period over which cost is expected to be recognized (in years) 3 years 5 months 8 days
Stock Options  
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]  
Unrecognized stock-based compensation cost $ 14,933
Weighted-average period over which cost is expected to be recognized (in years) 3 years 6 months 18 days
v3.26.1
Income Taxes - Schedule of Income Taxes Provision (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Current tax expense:    
Federal $ 0 $ 0
State and local 0 683
Total current tax expense 0 683
Deferred tax benefit:    
Federal (3,516) 0
State and local (1,013) 0
Total deferred tax benefit (4,529) 0
Total income tax (benefit) expense $ (4,529) $ 683
v3.26.1
Income Taxes - Schedule of Deferred Taxes (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Deferred tax assets:      
Net operating loss carryforwards $ 5,599 $ 3,078  
R&D tax credit 10,692 2,443  
Capitalized R&D expenses 16,039 5,617  
Capitalized start-up expenses 34,210 15,628  
Advance payment 5,267 0  
Operating lease liabilities 305 216  
Stock-based compensation 2,598 394  
Other 15 73  
Accrued expenses 2,079 0  
Deferred tax assets 76,804 27,449  
Valuation allowance (71,625) (26,775) $ (11,184)
Total deferred tax assets 5,179 674  
Deferred tax liabilities:      
Indefinite-lived intangible assets (5,794) 0  
Right-of-use assets (292) (207)  
Unrealized gain on marketable debt securities (248) (467)  
Total deferred tax liabilities (6,334) (674)  
Net deferred tax liabilities $ (1,155)    
Net deferred tax liabilities   $ 0  
v3.26.1
Income Taxes - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Tax Credit Carryforward [Line Items]      
Operating loss carryforwards (approximately)   $ 14,739  
Operating loss carryforwards, not subject to expiration $ 22,073    
Unrecognized tax benefits 1,435 271 $ 0
Domestic Tax Jurisdiction      
Tax Credit Carryforward [Line Items]      
Operating loss carryforwards (approximately) 23,694    
State and Local Jurisdiction      
Tax Credit Carryforward [Line Items]      
Operating loss carryforwards (approximately) 9,748    
Research Tax Credit Carryforward      
Tax Credit Carryforward [Line Items]      
Unamortized capitalized research and development costs 76,130 26,770  
Research Tax Credit Carryforward | Domestic Tax Jurisdiction      
Tax Credit Carryforward [Line Items]      
Tax credit carryforward (approximately) 12,128 2,714  
Start-Up Costs Tax Credit Carryforward      
Tax Credit Carryforward [Line Items]      
Capitalized start-up costs $ 162,370 $ 74,040  
Capitalized start-up costs, amortization period 180 months    
v3.26.1
Income Taxes - Schedule of Income Tax Rate Reconciliation (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Amount    
U.S. federal statutory tax rate $ (23,140) $ (15,316)
State and local taxes, net of federal benefit (a) (1,013) 539
Effect of change in tax laws or rates enacted in current period 0 0
Tax credits    
R&D tax credits (9,359) (1,290)
Change in valuation allowances 43,952 16,011
Nontaxable and nondeductible items    
Nondeductible executive compensation 10,275 242
Change in fair value of simple agreements for future equity 0 5,852
Transaction costs 0 (1,555)
Interest expense 0 (1,190)
Stock-based compensation (26,750) (2,981)
Other 342 100
Changes in unrecognized tax benefits 1,164 271
Total income tax (benefit) expense $ (4,529) $ 683
Percent    
U.S. federal statutory tax rate 21.00% 21.00%
State and local taxes, net of federal benefit (a) 0.90% (0.70%)
Effect of change in tax laws or rates enacted in current period 0.00% 0.00%
Tax credits    
R&D tax credits 8.50% 1.80%
Change in valuation allowances (39.90%) (21.30%)
Nontaxable and nondeductible items    
Nondeductible executive compensation (9.30%) (0.30%)
Change in fair value of simple agreements for future equity 0.00% (8.00%)
Transaction costs 0.00% 2.10%
Interest expense 0.00% 1.60%
Stock-based compensation 24.30% 4.10%
Other (0.30%) (0.80%)
Changes in unrecognized tax benefits (1.10%) (0.40%)
Effective tax rate 4.10% (0.90%)
v3.26.1
Income Taxes - Rollforward Of Deferred Tax Assets Valuation Allowance (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Deferred Tax Asset, Net of Valuation Allowance [Roll Forward]    
Valuation allowance for deferred tax assets - beginning of year $ 26,775 $ 11,184
Change in valuation allowance recognized during the year 219 (467)
Valuation allowance for deferred tax assets - end of year 71,625 26,775
Income Tax Expense (Benefit) | Domestic Tax Jurisdiction    
Deferred Tax Asset, Net of Valuation Allowance [Roll Forward]    
Change in valuation allowance recognized during the year 43,952 16,011
Income Tax Expense (Benefit) | State and Local Jurisdiction    
Deferred Tax Asset, Net of Valuation Allowance [Roll Forward]    
Change in valuation allowance recognized during the year $ 679 $ 47
v3.26.1
Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Unrecognized Tax Benefits [Roll Forward]    
Balance at beginning of year $ 271 $ 0
Additions for tax positions taken in prior year 228 142
Additions for tax positions related to the current year 936 129
Balance at end of year $ 1,435 $ 271
v3.26.1
Income Taxes - Schedule of Income Taxes Paid (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Income Tax Paid, by Individual Jurisdiction [Line Items]    
Federal   $ 223
Total $ 2,464 907
California    
Income Tax Paid, by Individual Jurisdiction [Line Items]    
State and local $ 2,464 550
New York City    
Income Tax Paid, by Individual Jurisdiction [Line Items]    
State and local   123
Other    
Income Tax Paid, by Individual Jurisdiction [Line Items]    
State and local   $ 11
v3.26.1
Retirement Plan (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Retirement Benefits [Abstract]    
Employer matching contribution, percent of match 4.00%  
Contributions to plan amount $ 820 $ 487
v3.26.1
Commitments and Contingencies (Details)
Dec. 31, 2025
USD ($)
Commitments and Contingencies Disclosure [Abstract]  
Loss contingency accrual $ 0
v3.26.1
Segment Information (Details) - segment
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Segment Reporting [Abstract]    
Number of reportable segments 1 1
v3.26.1
Related Party Transactions (Details) - Klein Group LLC - USD ($)
$ in Thousands
 12 Months Ended
Jun. 25, 2025
Dec. 31, 2025
Related Party Transaction [Line Items]    
Advisory agreement term 1 year  
Advisory agreement, quarterly retainer fee $ 250  
Advisory agreement, payment of quarterly retainer fee   $ 500
v3.26.1
Subsequent Events (Details) - At The Market Offering - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 12 Months Ended
Dec. 04, 2025
Sep. 11, 2025
Sep. 03, 2025
Jun. 02, 2025
Jan. 28, 2026
Dec. 31, 2025
Aug. 27, 2025
Sep. 03, 2025
Dec. 31, 2025
Subsequent Event [Line Items]                  
Number of shares issued and offered (in shares)   1,925,066       3,397,872 5,458,953   10,781,891
Legacy Oklo price per share upon conversion (in dollars per share)   $ 72.72       $ 88.29 $ 73.27   $ 88.29
Proceeds from issuance of common stock, gross $ 1,500,000 $ 139,999 $ 139,999 $ 400,000   $ 300,000 $ 400,000 $ 539,999 $ 821,999
Subsequent event                  
Subsequent Event [Line Items]                  
Number of shares issued and offered (in shares)         12,376,352        
Legacy Oklo price per share upon conversion (in dollars per share)         $ 96.95        
Proceeds from issuance of common stock, gross         $ 1,199,868