ADTRAN HOLDINGS, INC., 10-Q filed on 5/5/2026
Quarterly Report
v3.26.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2026
May 01, 2026
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Entity Registrant Name ADTRAN Holdings, Inc.  
Trading Symbol ADTN  
Entity Central Index Key 0000926282  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   80,998,100
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Shell Company false  
Entity File Number 001-41446  
Entity Tax Identification Number 87-2164282  
Entity Address, Address Line One 901 Explorer Boulevard  
Entity Address, City or Town Huntsville  
Entity Address, State or Province AL  
Entity Address, Postal Zip Code 35806-2807  
City Area Code 256  
Local Phone Number 963-8000  
Entity Incorporation, State or Country Code DE  
Document Quarterly Report true  
Document Transition Report false  
Title of 12(b) Security Common Stock, Par Value $0.01 per share  
Security Exchange Name NASDAQ  
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Current Assets        
Cash and cash equivalents $ 88,270 $ 95,696    
Accounts receivable, less allowance for credit losses of $1,652 and $1,318 as of March 31, 2026 and December 31, 2025, respectively 215,473 210,687    
Other receivables 10,292 7,046    
Inventory, net 209,003 215,736    
Income tax receivable 2,971 3,667    
Prepaid expenses and other current assets 62,492 55,317    
Short-term investments - deferred compensation 33,813 35,174    
Assets held for sale 11,901 11,901    
Total Current Assets 634,215 635,224    
Property, plant and equipment, net 123,849 124,384    
Goodwill 59,003 59,983    
Intangible assets, net 281,280 294,047    
Deferred tax assets 16,223 16,481    
Other non-current assets 69,560 73,352    
Long-term investments 937 1,022    
Total Assets 1,185,067 1,204,493    
Current Liabilities        
Accounts payable 170,605 167,337    
Unearned revenue 90,752 87,541    
Accrued expenses and other liabilities 31,736 33,690    
Accrued wages and benefits 23,449 32,203    
Deferred compensation liability 37,051 37,447    
Income tax payable 5,613 3,642    
Total Current Liabilities 359,206 361,860    
Non-current revolving credit agreement outstanding 25,000 25,000    
Non-current convertible senior notes, net of debt issuance costs 193,425 193,038    
Deferred tax liabilities 26,776 27,453    
Non-current unearned revenue 26,227 27,143    
Non-current pension liability 6,305 6,277    
Non-current lease obligations 24,940 27,000    
Other non-current liabilities 16,646 17,564    
Total Liabilities 678,525 685,335    
Commitments and contingencies (see Note 17)    
Redeemable Non-Controlling Interest 369,017 373,328    
Equity        
Common stock, par value $0.01 per share; 200,000 shares authorized; 80,803 shares issued and 80,546 outstanding as of March 31, 2026 and 80,188 shares issued and 79,926 outstanding as of December 31, 2025 808 802    
Additional paid-in capital 803,031 801,269    
Accumulated other comprehensive income 70,046 78,877    
Retained deficit (731,345) (730,010)    
Less treasury stock at cost: 257 and 262 shares as of March 31, 2026 and December 31, 2025, respectively (5,015) (5,108)    
Total Equity 137,525 145,830 $ 138,893 $ 126,951
Total Liabilities and Equity $ 1,185,067 $ 1,204,493    
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Statement of Financial Position [Abstract]    
Accounts receivable, allowance for credit losses $ 1,652 $ 1,318
Common stock, par value $ 0.01 $ 0.01
Common stock, shares authorized 200,000,000 200,000,000
Common stock, shares issued 80,803,000 80,188,000
Common stock, shares outstanding 80,546,000 79,926,000
Treasury stock, shares 257,000 262,000
v3.26.1
Condensed Consolidated Statements of Loss (Unaudited) - USD ($)
shares in Thousands, $ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Revenue    
Total Revenue $ 286,086 $ 247,744
Cost of Revenue    
Total Cost of Revenue 173,098 152,568
Gross Profit 112,988 95,176
Selling, general and administrative expenses 55,836 50,285
Research and development expenses 50,777 48,859
Operating Income (Loss) 6,375 (3,968)
Interest and dividend income 300 126
Interest expense (4,241) (4,761)
Net investment loss (850) (1,686)
Other income, net 1,263 944
Income (Loss) Before Income Taxes 2,847 (9,345)
Income tax (expense) benefit (1,917) 397
Net Income (Loss) 930 (8,948)
Less: Net Income attributable to non-controlling interest [1] 2,251 2,319
Net Loss attributable to ADTRAN Holdings, Inc. $ (1,321) $ (11,267)
Weighted average shares outstanding – basic 80,321 79,534
Weighted average shares outstanding – diluted 80,321 79,534
Loss per common share attributable to ADTRAN Holdings, Inc. - basic [2] $ (0.01) $ (0.14)
Loss per common share attributable to ADTRAN Holdings, Inc. - diluted [2] $ (0.01) $ (0.14)
Network Solutions [Member]    
Revenue    
Total Revenue $ 237,941 $ 202,217
Cost of Revenue    
Total Cost of Revenue 154,648 134,241
Gross Profit 83,293 67,976
Services & Support [Member]    
Revenue    
Total Revenue 48,145 45,527
Cost of Revenue    
Total Cost of Revenue 18,450 18,327
Gross Profit $ 29,695 $ 27,200
[1] For the three months ended March 31, 2026 and 2025 we accrued $2.2 million and $2.4 million, respectively, of net income attributable to non-controlling interest, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA.
[2] Loss per common share attributable to ADTRAN Holdings, Inc. - basic and diluted - reflects a $0.3 million and a $(3) thousand effect of redemption of RNCI for the three months ended March 31, 2026 and 2025. See Note 15 for additional information.
v3.26.1
Condensed Consolidated Statements of Loss (Unaudited) (Parenthetical) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Net gain (loss) attributable to redeemable non-controlling interest [1] $ 2,251 $ 2,319
Effect of redemption of RNCI 301 (3)
Post-DPLTA [Member]    
Recurring cash compensation earned $ 2,200 $ 2,400
[1] For the three months ended March 31, 2026 and 2025 we accrued $2.2 million and $2.4 million, respectively, of net income attributable to non-controlling interest, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA.
v3.26.1
Condensed Consolidated Statements of Comprehensive (Loss) Income (Unaudited) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Statement of Comprehensive Income [Abstract]    
Net Income (Loss) $ 930 $ (8,948)
Other Comprehensive (Loss) Income, net of tax    
Defined benefit plan adjustments (66) 131
Foreign currency translation (loss) gain (8,765) 20,247
Other Comprehensive (Loss) Income, net of tax (8,831) 20,378
Comprehensive (Loss) Income, net of tax (7,901) 11,430
Less: Comprehensive Income attributable to non-controlling interest 2,251 2,319
Comprehensive (Loss) Income attributable to ADTRAN Holdings, Inc., net of tax $ (10,152) $ 9,111
v3.26.1
Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($)
shares in Thousands, $ in Thousands
Total
Adtran Networks SE [Member]
Common Stock [Member]
Additional Paid-in Capital [Member]
Additional Paid-in Capital [Member]
Adtran Networks SE [Member]
Retained Deficit [Member]
Treasury Stock [Member]
Accumulated Other Comprehensive Income [Member]
Beginning Balance at Dec. 31, 2024 $ 126,951   $ 795 $ 808,913   $ (688,813) $ (5,198) $ 11,254
Beginning Balance, Shares at Dec. 31, 2024     79,483          
Net (loss) income (8,948)         (8,948)    
Annual recurring compensation earned (2,319)         (2,319)    
Other comprehensive income (loss), net of tax 20,378             20,378
Deferred compensation adjustments, net of tax 38     (52)     90  
ADTRAN RSUs and restricted stock vested (1,170)   $ 4     (1,174)    
ADTRAN RSUs and restricted stock vested, Shares     373          
ADTRAN Stock options exercised 756   $ 1     755    
ADTRAN Stock options exercised, Shares     113          
Redemption of redeemable non-controlling interest (3)         (3)    
ADTRAN Stock-based compensation expense 2,062 $ 1,148   2,062 $ 1,148      
Ending Balance at Mar. 31, 2025 138,893   $ 800 812,071   (700,502) (5,108) 31,632
Ending Balance, Shares at Mar. 31, 2025     79,969          
Beginning Balance at Dec. 31, 2025 $ 145,830   $ 802 801,269   (730,010) (5,108) 78,877
Beginning Balance, Shares at Dec. 31, 2025 80,188   80,188          
Net (loss) income $ 930         930    
Annual recurring compensation earned (2,251)         (2,251)    
Other comprehensive income (loss), net of tax (8,831)             (8,831)
Dividends accrued on unvested restricted stock units (7)         (7)    
Deferred compensation adjustments, net of tax 36     (57)     93  
ADTRAN RSUs and restricted stock vested (1,671)   $ 4     (1,675)    
ADTRAN RSUs and restricted stock vested, Shares     398          
ADTRAN Stock options exercised 1,369   $ 2     1,367    
ADTRAN Stock options exercised, Shares     217          
Redemption of redeemable non-controlling interest 301         301    
ADTRAN Stock-based compensation expense 1,819     1,819        
Ending Balance at Mar. 31, 2026 $ 137,525   $ 808 $ 803,031   $ (731,345) $ (5,015) $ 70,046
Ending Balance, Shares at Mar. 31, 2026 80,803   80,803          
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Cash flows from operating activities:    
Net Income (Loss) $ 930 $ (8,948)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:    
Depreciation and amortization 24,916 21,596
Amortization of debt issuance cost 374 320
Amortization of convertible notes issuance costs 386  
Loss on investments, net 822 1,631
Net loss on disposal of property, plant and equipment 60 13
Stock-based compensation expense 1,819 3,210
Deferred income taxes (244) (157)
Inventory reserves 143 3,339
Changes in operating assets and liabilities:    
Accounts receivable, net (6,192) 16,011
Other receivables (3,312) (1,141)
Income taxes receivable, net 896 (690)
Inventory 4,671 10,345
Prepaid expenses, other current assets and other assets (5,558) 1,504
Accounts payable 366 (4,222)
Accrued expenses and other liabilities (9,197) 352
Income taxes payable 1,790 18
Net cash provided by operating activities 12,670 43,181
Cash flows from investing activities:    
Purchases of property, plant and equipment (7,505) (7,399)
Purchases of intangibles - developed technology (8,435) (11,296)
Proceeds from sales and maturities of available-for-sale investments 736 660
Purchases of available-for-sale investments (75) (170)
Payments for beneficial interest in securitized accounts receivable (574) (133)
Net cash used in investing activities (15,853) (18,338)
Cash flows from financing activities:    
Tax withholdings related to stock-based compensation settlements (1,645) (420)
Proceeds from stock option exercises 1,369 756
Payments on financing agreement (1,400)  
Redemption of redeemable non-controlling interest (8) (12)
Net cash (used in) provided by financing activities (1,684) 324
Net (decrease) increase in cash and cash equivalents (4,867) 25,167
Effect of exchange rate changes (2,559) 133
Cash and cash equivalents, beginning of period 95,696 76,021
Cash and cash equivalents, end of period 88,270 101,321
Supplemental disclosure of cash financing activities:    
Cash paid for interest 4,451 4,129
Cash (refund) paid for income taxes, net (814) 2,367
Cash used in operating activities related to operating leases 2,425 2,696
Supplemental disclosure of non-cash investing and financing activities:    
Redemption of redeemable non-controlling interest 301 (3)
Right-of-use assets obtained in exchange for lease obligations 183 1,893
Purchases of property, plant and equipment included in accounts payable $ 1,296 $ 1,162
v3.26.1
Pay vs Performance Disclosure - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Pay vs Performance Disclosure    
Net Income (Loss) $ (1,321) $ (11,267)
v3.26.1
Insider Trading Arrangements
3 Months Ended
Mar. 31, 2026
Trading Arrangements, by Individual  
Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
v3.26.1
Summary of Significant Accounting Policies
3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies

GENERAL

ADTRAN Holdings, Inc. (“Adtran” or the “Company”) is a leading global provider of networking and communications platforms, software, systems and services focused on the broadband access market, serving a diverse domestic and international customer base in multiple countries that includes large, medium and small Service Providers, alternative Service Providers, such as utilities, municipalities and fiber overbuilders, cable/MSOs, SMBs and distributed enterprises, including Fortune 500 companies with sophisticated business continuity applications; and federal, state and local government agencies. Our innovative solutions and services enable voice, data, video and internet-communications across a variety of network infrastructures and are currently in use by millions worldwide. We support our customers through our direct global sales organization and distribution networks. Our success depends upon our ability to increase unit volume and market share through the introduction of new products and succeeding generations of products having optimal selling prices and increased functionality as compared to both the prior generation of a product and to the products of competitors in order to gain market share. To service our customers and grow revenue, we are continually conducting research and developing new products addressing customer needs and testing those products for the specific requirements of the particular customers. We offer a broad portfolio of flexible software and hardware network solutions and services that enable Service Providers to meet today’s service demands, while enabling them to transition to the fully converged, scalable, highly-automated, cloud-controlled voice, data, internet and video network of the future. In addition to our global headquarters in Huntsville, Alabama, and our European headquarters in Munich, Germany, we have sales and research and development facilities in strategic global locations.

The Company solely owns ADTRAN, Inc. and is the majority shareholder of Adtran Networks. ADTRAN, Inc. is a leading global provider of open, disaggregated networking and communications solutions. Adtran Networks is a global provider of network solutions for data, storage, voice and video services. We believe that the combined technology portfolio can best address current and future customer needs for high-speed connectivity from the network core to the end consumer, especially upon the convergence of solutions at the network edge.

Domination and Profit and Loss Transfer Agreement, Liquidity, Credit Facility and Notes Offering

The DPLTA between the Company, as the controlling company, and Adtran Networks, as the controlled company, which was executed on December 1, 2022, became effective on January 16, 2023, as a result of its registration with the commercial register (Handelsregister) of the local court (Amtsgericht) at the registered seat of Adtran Networks (Jena).

Under the DPLTA, subject to certain limitations pursuant to applicable law and the specific terms of the DPLTA, (i) the Company is entitled to issue binding instructions to the management board of Adtran Networks, (ii) Adtran Networks will transfer its annual profit to the Company, subject to, among other things, the creation or dissolution of certain reserves, and (iii) the Company will absorb the annual net loss incurred by Adtran Networks. The Company’s payment obligation in satisfaction of the requirement that it absorb Adtran Networks’ annual net loss applied to the net loss generated by Adtran Networks in 2025 and it will apply to any net loss generated by Adtran Networks in 2026.

Pursuant to the terms of the DPLTA, each Adtran Networks shareholder (other than the Company) has received an offer to elect either (1) to remain an Adtran Networks shareholder and receive from us an Annual Recurring Compensation payment, or (2) to receive Exit Compensation plus guaranteed interest. The guaranteed interest under the Exit Compensation is calculated from the effective date of the DPLTA to the date the shares are tendered, less any Annual Recurring Compensation paid. The guaranteed interest rate is 5.0% plus a variable component (according to the German Civil Code) that was 1.27% as of March 31, 2026. Assuming all the minority holders of currently outstanding Adtran Networks shares were to elect the second option, we would be obligated to make aggregate Exit Compensation payments, including guaranteed interest, of approximately €304.4 million or approximately $351.7 million, based on an exchange rate as of March 31, 2026, and reflecting interest accrued through March 31, 2026 during the pendency of the appraisal proceedings discussed below. Shareholders electing the first option of Annual Recurring Compensation may later elect the second option. The opportunity for outside Adtran Networks shareholders to tender Adtran Networks shares in exchange for Exit Compensation had been scheduled to expire on March 16, 2023. However, due to the appraisal proceedings that were initiated in 2023 in accordance with applicable German law, this time period for tendering shares has been extended pursuant to the German Stock Corporation Act (Aktiengesetz) and will end two months after the date on which a final decision in such appraisal proceedings has been published in the Federal Gazette (Bundesanzeiger). Following the court's decision on a procedural matter in the DPLTA appraisal proceedings on July 14, 2025, the trial on the merits of the DPLTA has recommenced. It is expected to take a minimum of 12 months for a ruling of the court on the merits and such ruling will most likely be appealed, which would be expected to take an additional 12-24 months to be resolved. Accordingly, the Company does not expect a final decision on the DPLTA appraisal proceedings to be rendered and published prior to 2027, and most likely not until 2028 or beyond.

Additionally, our obligation to pay Annual Recurring Compensation under the DPLTA is a continuing payment obligation, which will amount to approximately €7.8 million (or $9.0 million based on the current exchange rate) per year assuming none of the minority Adtran Networks shareholders as of March 31, 2026 were to elect Exit Compensation. The foregoing amounts do not reflect any potential increase in payment obligations that we may have depending on the outcome of ongoing appraisal proceedings in Germany. The Annual Recurring Compensation is due on the third banking day following the ordinary general shareholders’ meeting of Adtran Networks for the respective preceding fiscal year (but in any event within eight months following expiration of the fiscal year). With respect to the 2025 fiscal year, Adtran Networks’ ordinary general shareholder meeting is scheduled for the second quarter of 2026, and the Annual Recurring Compensation will be due on the third banking day following the meeting. During the three months ended March 31, 2026 and 2025, we accrued $2.2 million and $2.4 million, respectively, in Annual Recurring Compensation. The Annual Recurring Compensation is reflected as an increase to retained deficit in the Condensed Consolidated Balance Sheets.

On July 18, 2022, ADTRAN, Inc., as the borrower, and ADTRAN Holdings, Inc. entered into a credit agreement with a syndicate of banks, including Wells Fargo Bank, National Association, as administrative agent (“Administrative Agent”), and the other lenders named therein (“Credit Agreement”), which has since been amended six times. The Company had access to $319.2 million on its Credit Facility for future borrowings based on debt covenant compliance metrics. The financial covenants under the Credit Agreement, as amended, require the Company to maintain a Consolidated Total Net Leverage Ratio of 5.00x, a Consolidated Senior Secured Net Leverage Ratio of 3.25x (4.0x to 3.5x during a Springing Covenant Period) and a Consolidated Fixed Charge Coverage Ratio of 1.25x (as such terms are defined in the Credit Agreement). In addition, during a Springing Covenant Period the cash and cash equivalents of the credit parties must be at least $50.0 million and the cash and cash equivalents of the Company and its subsidiaries must be at least $70.0 million. The Credit Agreement matures in July 2027. The Company intends to refinance or replace the existing Credit Agreement with a new credit facility during the second quarter of 2026. There can be no assurances that this renewal will occur on terms acceptable to the Company, or at all.

On October 18, 2022, the Company's Board of Directors authorized the Company to purchase additional shares of Adtran Networks through open market purchases not to exceed 15,346,544 shares.

As of March 31, 2026, and as of the date of issuance of these financial statements, the Company has sufficient liquidity to meet the majority of its payment obligations under the DPLTA pertaining to Exit Compensation. For the three months ended March 31, 2026, approximately 0.2 million shares of Adtran Networks stock were tendered to the Company and Exit Compensation of €3.6 million or approximately $4.1 million are to be settled in cash in April 2026. For the three months ended March 31, 2025, less than one thousand shares of Adtran Networks stock were tendered to the Company and exit compensation payments of €12 thousand or $13 thousand based on the applicable exchange rates at the time of the transaction were paid to Adtran Networks shareholders. We believe the probability that more than a small minority of Adtran Networks shareholders elect to receive Exit Compensation in the next twelve months is remote based on the following factors: (i) the shareholders can exercise their right to receive the Exit Compensation until two months after publication of the final decision in the appraisal proceedings and we do not expect the final decision to be published within the next 12 months; (ii) the diverse base of shareholders that must make this election on an individual shareholder basis; (iii) the fact the date of a decision by the court on the merits of the case is uncertain, it will most likely take a minimum of 12 months for a ruling and, thereafter, an expected appeal process will take a further 12-24 months to resolve; (iv) the current guaranteed Annual Recurring Compensation payment; and (v) the current trading value of Adtran Networks shares.

Moreover, on September 19, 2025, the Company issued $201.3 million aggregate principal amount of convertible senior notes due 2030 (the “Notes”). The Notes accrue interest at a rate of 3.75% per annum, payable semi-annually in arrears on March 15 and September 15 of each year, beginning March 15, 2026. Unless repurchased earlier, redeemed, or converted, the Notes will mature on September 15, 2030. After deducting the initial purchasers’ discounts, commissions, and estimated offering expenses, the Company received net proceeds of $192.6 million.

The Company believes that its cash and cash equivalents, working capital management initiatives and availability to access cash under the Wells Fargo credit facility or other future sources of capital will be adequate to meet our business operating requirements, our capital expenditures and our expected obligations under both the Notes and the DPLTA, including anticipated levels of Exit Compensation, as well as to support our ability to continue to comply with our debt covenants under the Credit Facility for at least the next twelve months, from the issuance of these financial statements. See Note 10, Credit Agreements, for additional information regarding the terms of the Amendments of the Wells Fargo Credit Agreement.

1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements of ADTRAN Holdings, Inc. and its subsidiaries have been prepared pursuant to the rules and regulations of the SEC applicable to interim financial information presented in Quarterly Reports on Form 10-Q. Accordingly, certain information and notes required by generally accepted accounting principles in the United States of America (“U.S. GAAP”) for complete financial statements are not included herein. The December 31, 2025, Condensed Consolidated Balance Sheet is derived from audited financial statements but does not include all disclosures required by U.S. GAAP for annual financial statements.

In the opinion of management, all adjustments necessary to fairly state these interim statements have been recorded and are of a normal and recurring nature. The results of operations for an interim period are not necessarily indicative of the results for the full year. The interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in ADTRAN Holdings, Inc. Annual Report on Form 10-K for the year ended December 31, 2025, filed with the SEC on February 26, 2026.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expense during the reporting period. Significant estimates include allowance for credit losses on accounts receivable and contract assets, excess and obsolete inventory reserves, determination and accrual of the deferred revenue related to performance obligations under contracts with customers, estimated costs to complete obligations associated with deferred and accrued revenue and network installations, estimated income tax provision and income tax contingencies, fair value of stock-based compensation, assessment of goodwill and other intangibles for impairment, estimated lives of intangible assets, estimates of intangible assets upon measurement, estimated pension liability and fair value of investments and estimated contingent liabilities. Actual amounts could differ significantly from these estimates.

We assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to us and the unknown future impacts of ongoing inflationary pressures, continued elevated interest rates, instability in the financial services industry, currency fluctuations and political tensions as of March 31, 2026, and through the date of this report. These conditions could result in further impacts to the Company's consolidated financial statements in future reporting periods. The accounting matters assessed included, but were not limited to, the allowance for credit losses, stock-based compensation, carrying value of goodwill, intangibles and other long-lived assets, financial assets, valuation allowances for tax assets, revenue recognition and costs of revenue.

During the three months ended March 31, 2026, there were no other significant changes to our critical accounting policies or estimates from those described in the financial statements contained in the 2025 Form 10-K.

Recent Accounting Pronouncements Not Yet Adopted

In September 2025, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2025-06, "Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software," which is intended to modernize the accounting for the costs of internal-use software given the evolution of software development to the incremental and iterative development method. The amendments remove all references to prescriptive and sequential development stages and, instead, require an entity to start capitalizing software costs when management has authorized and committed to funding the software project, and it is probable that the project will be completed and the software will be used to perform the function intended. The amendments are effective for annual reporting periods beginning after December 15, 2027, and interim reporting periods within those annual reporting periods. Early adoption is permitted as of the beginning of an annual reporting period with the amendments to be applied using a prospective, modified or retrospective transition approach. The Company is currently evaluating the impact of adopting this guidance on the consolidated financial statements.

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, as amended by ASU 2025-01, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date", which applies to all public business entities (PBEs) and is intended to enhance disclosures about specific types of expenses included in the expense captions presented on the face of the income statement as well as disclosures about selling expenses. The amendments are effective prospectively for annual periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption and retrospective application are permitted. The Company is currently evaluating the effect that adoption of ASU 2024-03 will have on our disclosures.

Recently Adopted Accounting Pronouncements

There are currently no recently adopted accounting pronouncements that are expected to have a material effect on the Condensed Consolidated Financial Statements.

v3.26.1
Revenue and Receivables
3 Months Ended
Mar. 31, 2026
Revenue from Contract with Customer [Abstract]  
Revenue and Receivables

2. REVENUE AND RECEIVABLES

The following is a description of the principal activities from which revenue is generated by reportable segment:

Network Solutions Segment - Includes hardware and software products that enable a digital future which support the Company's Subscriber, Access & Aggregation, and Optical Networking Solutions.

Services & Support Segment - Includes network design, implementation, maintenance and cloud-hosted services supporting the Company's Subscriber, Access & Aggregation, and Optical Networking Solutions.

Revenue by Category

In addition to the Company's reportable segments, revenue is also reported for the following three categories – Subscriber Solutions, Access & Aggregation Solutions and Optical Networking Solutions.

Our Subscriber Solutions portfolio is used by Service Providers to terminate their access services infrastructure at the customer premises while providing an immersive and interactive experience for residential, business and wholesale subscribers. This revenue category includes hardware- and software-based products and services. These solutions include fiber termination solutions for residential, business and wholesale subscribers, Wi-Fi access solutions for residential and business subscribers, Ethernet switching and network edge virtualization solutions for business subscribers, and cloud software solutions covering a mix of subscriber types.

Our Access & Aggregation Solutions are solutions that are used by communications Service Providers to connect residential subscribers, business subscribers and mobile radio networks to the Service Providers’ metro network, primarily through fiber-based connectivity. This revenue category includes hardware- and software-based products and services. Our solutions within this category are a mix of fiber access and aggregation platforms, precision network synchronization and timing solutions, and access orchestration solutions that ensure highly reliable and efficient network performance.

Our Optical Networking Solutions are used by communications Service Providers, internet content providers and large-scale enterprises to securely interconnect metro and regional networks over fiber. This revenue category includes hardware- and software-based products and services. Our solutions within this category include open optical terminals, open line systems, optical subsystems and modules, network infrastructure assurance systems, and automation platforms that are used to build high-scale, secure and assured optical networks.

The following tables disaggregate revenue by reportable segment and revenue category:

 

 

Three Months Ended

 

 

 

March 31, 2026

 

 

March 31, 2025

 

(In thousands)

 

Network Solutions

 

 

Services & Support

 

 

Total

 

 

Network Solutions

 

 

Services & Support

 

 

Total

 

Subscriber Solutions

 

$

90,193

 

 

$

8,047

 

 

$

98,240

 

 

$

71,748

 

 

$

8,662

 

 

$

80,410

 

Optical Networking Solutions

 

 

70,952

 

 

 

26,374

 

 

 

97,326

 

 

 

54,622

 

 

 

23,576

 

 

 

78,198

 

Access & Aggregation Solutions

 

 

76,796

 

 

 

13,724

 

 

 

90,520

 

 

 

75,847

 

 

 

13,289

 

 

 

89,136

 

Total

 

$

237,941

 

 

$

48,145

 

 

$

286,086

 

 

$

202,217

 

 

$

45,527

 

 

$

247,744

 

 

The aggregate amount of transaction price allocated to remaining performance obligations ("RPO") that have not been satisfied as of March 31, 2026 related to non-cancellable contractual maintenance agreements, non-cancellable contractual SaaS and subscription services, and non-cancellable hardware contracts amounted to $159.2 million. The majority of the Company's performance obligations will generally be satisfied within a year and any remaining performance obligations are typically recognized over one to three years.

The following table provides information about accounts receivable, contract assets and unearned revenue from contracts with customers:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Accounts receivable, net

 

$

215,473

 

 

$

210,687

 

Contract assets(1)

 

$

533

 

 

$

432

 

Unearned revenue

 

$

90,752

 

 

$

87,541

 

Non-current unearned revenue

 

$

26,227

 

 

$

27,143

 

 

(1) Included in other receivables on the Condensed Consolidated Balance Sheets.

Accounts Receivable

The allowance for credit losses was $1.7 million and $1.3 million as of March 31, 2026, and December 31, 2025, respectively, related to accounts receivable.

Receivables Purchase Agreements

On July 1, 2024, the Company entered into a receivables purchase agreement (the “Factoring Agreement”) with a third-party financial institution (the “Factor”), which accelerates receivable collection and helps to better manage cash flow. Total accounts receivables factored as of the end of March 31, 2026, totaled $26.1 million of which $3.9 million was retained pursuant to the Factoring Agreement in the reserve account. Total accounts receivables factored as of the end of March 31, 2025, totaled $11.2 million of which $3.7 million was retained pursuant to the Factoring Agreement in the reserve account. The Factoring Agreement provides for up to $40.0 million in factoring capacity, subject to eligible receivables and reserve requirements, secured by the receivables.

During the three months ended March 31, 2026 and 2025, the Company received $51.8 million and $31.8 million, in cash proceeds from the Factoring Agreement, respectively. The cost of the Factoring Agreement is included in interest expense in the Condensed Consolidated Statements of Loss and totaled $0.5 million and $0.3 million for the three months ended March 31, 2026 and 2025, respectively.

Contract Assets

No allowance for credit losses was recorded for the three months ended March 31, 2026 and 2025, respectively, related to contract assets.

Unearned Revenue

Of the outstanding unearned revenue balances as of December 31, 2025, $23.1 million were recognized as revenue during the three months ended March 31, 2026. Of the $52.7 outstanding unearned revenue balances as of December 31, 2024, $21.9 million were recognized as revenue during the three months ended March 31, 2025.

v3.26.1
Income Taxes
3 Months Ended
Mar. 31, 2026
Income Tax Disclosure [Abstract]  
Income Taxes

3. INCOME TAXES

The Company’s effective tax rate changed from a benefit of 4.2% of pre-tax loss for the three months ended March 31, 2025, to an expense of 67.3% of pre-tax income for the three months ended March 31, 2026. The change in the effective tax rate for the three months ended March 31, 2026, was driven primarily by loss jurisdictions for which the recognition of tax benefits on pre-tax losses incurred during the first quarter of 2026 were limited due to valuation allowance.

The Company continually reviews the adequacy of its valuation allowance and recognizes the benefits of deferred tax assets only as the assessment indicates that it is more likely than not that the deferred tax assets will be recognized in accordance with ASC 740, Income Taxes. As of March 31, 2026, the Company had net deferred tax assets totaling $113.9 million, and a valuation allowance totaling $124.5 million against those deferred tax assets. Our assessment of the realizability of our deferred tax assets includes the evaluation of historical operating results, as well as the evaluation of evidence which requires significant judgment, including the evaluation of our three-year cumulative income position, future taxable income projections and tax planning strategies. Should management’s conclusion change in the future and an additional valuation allowance, or a partial or full release of the valuation allowance becomes necessary, it may have a material effect on our consolidated financial statements.

v3.26.1
Stock-Based Compensation
3 Months Ended
Mar. 31, 2026
Share-Based Payment Arrangement [Abstract]  
Stock-Based Compensation

4. STOCK-BASED COMPENSATION

2024 Stock Incentive Plans

At the annual meeting of stockholders held on May 8, 2024, the Company’s stockholders approved, upon recommendation of the Board of Directors, the adoption of the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan (“2024 Employee Plan”) and the ADTRAN Holdings, Inc. 2024 Directors Stock Plan (“2024 Directors Plan”). Outstanding awards granted under the Company's prior equity incentive plans will remain subject to the terms of such applicable plans, and shares under such plans that are cancelled or forfeited will be available for issuance under the 2024 Employee Plan or the 2024 Directors Plan, as applicable.

As of March 31, 2026, 5.5 million shares were available for issuance pursuant to awards that may be made in the future under stockholder-approved equity plans.

For the three months ended March 31, 2026 and 2025, stock-based compensation expense was $1.8 million and $3.2 million, respectively.

PSUs, RSUs and Restricted Stock

The following table summarizes the PSUs, RSUs and restricted stock outstanding as of December 31, 2025, and March 31, 2026 and the changes that occurred during the three months ended March 31, 2026:

 

 

Number of
Shares
(in thousands)

 

 

Weighted Avg. Grant Date Fair Value
(per share)

 

Unvested PSUs, RSUs and restricted stock outstanding, December 31, 2025

 

 

1,967

 

 

$

10.70

 

PSUs, RSUs and restricted stock granted

 

 

95

 

 

$

8.88

 

PSUs, RSUs and restricted stock vested

 

 

(487

)

 

$

11.50

 

PSUs, RSUs and restricted stock forfeited

 

 

(59

)

 

$

19.32

 

Unvested PSUs, RSUs and restricted stock outstanding, March 31, 2026

 

 

1,516

 

 

$

9.99

 

The fair value of PSUs with performance conditions, RSUs and restricted stock is equal to the closing price of the Company's stock on the date of grant. The fair value of PSUs with market conditions is calculated using a Monte Carlo simulation valuation method.

As of March 31, 2026, total unrecognized compensation expense related to non-vested portion of performance-based PSUs, market-based PSUs, RSUs and restricted stock was approximately $12.1 million, which will be recognized over the remaining weighted-average period of 2.2 years. Unrecognized compensation expense will be adjusted for actual forfeitures.

v3.26.1
Investments
3 Months Ended
Mar. 31, 2026
Investments, Debt and Equity Securities [Abstract]  
Investments

5. INVESTMENTS

The Company has cash equivalents and investments which are held at fair value as follows:

 

 

 

 

 

Fair Value Measurements as of March 31, 2026 Using

 

(In thousands)

 

Fair Value

 

 

Quoted Prices
in Active
Market for
Identical
Assets
(Level 1)

 

 

Significant
Other
Observable
Inputs
(Level 2)

 

 

Significant Unobservable Inputs
(Level 3)

 

Cash equivalents

 

 

 

 

 

 

 

 

 

 

 

 

Money market funds (1)

 

$

246

 

 

$

246

 

 

$

 

 

$

 

Marketable equity securities

 

 

 

 

 

 

 

 

 

 

 

 

Marketable equity securities

 

 

937

 

 

 

937

 

 

 

 

 

 

 

Deferred compensation plan assets

 

 

33,813

 

 

 

33,813

 

 

 

 

 

 

 

Total

 

$

34,996

 

 

$

34,996

 

 

$

 

 

$

 

 

 

 

 

 

Fair Value Measurements as of December 31, 2025 Using

 

(In thousands)

Fair Value

 

 

Quoted Prices
in Active
Market for
Identical
Assets
(Level 1)

 

 

Significant
Other
Observable
Inputs
(Level 2)

 

 

Significant Unobservable Inputs
(Level 3)

 

Cash equivalents

 

 

 

 

 

 

 

 

 

 

 

Money market funds (1)

$

245

 

 

$

245

 

 

$

 

 

$

 

Marketable equity securities

 

 

 

 

 

 

 

 

 

 

 

Marketable equity securities

 

1,022

 

 

 

1,022

 

 

 

 

 

 

 

Deferred compensation plan assets

 

35,174

 

 

 

35,174

 

 

 

 

 

 

 

Total

$

36,441

 

 

$

36,441

 

 

$

 

 

$

 


(1) The money market fund balances of $0.2 million as of March 31, 2026 and December 31, 2025, are included in cash and cash equivalents on the balance sheet.

Market prices are obtained from a variety of industry standard data providers, large financial institutions and other third-party sources. These multiple market prices are used as inputs into a distribution-curve-based algorithm to determine the daily market value of each security.

U.S. GAAP establishes a three-level valuation hierarchy based upon observable and unobservable inputs for fair value measurement of financial instruments:


• Level 1 – Observable outputs; values based on unadjusted quoted prices for identical assets or liabilities in an active market;

• Level 2 – Significant inputs that are observable; values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly and

• Level 3 – Significant unobservable inputs; values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs could include information supplied by investees.

v3.26.1
Inventory
3 Months Ended
Mar. 31, 2026
Inventory Disclosure [Abstract]  
Inventory

6. INVENTORY

As of March 31, 2026 and December 31, 2025, inventory, net was comprised of the following:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Raw materials

 

$

80,069

 

 

$

78,230

 

Work in process

 

 

12,867

 

 

 

12,801

 

Finished goods

 

 

116,067

 

 

 

124,705

 

Total inventory, net

 

$

209,003

 

 

$

215,736

 

Inventory reserves are established for estimated excess and obsolete inventory equal to the difference between the cost of the inventory and the estimated net realizable value of the inventory based on estimated reserve percentages, which considers historical usage, known trends, inventory age and market conditions.

v3.26.1
Property, Plant and Equipment
3 Months Ended
Mar. 31, 2026
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment

7. PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment consisted of the following:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Engineering and other equipment

 

$

133,656

 

 

$

131,665

 

Building

 

 

52,374

 

 

 

52,586

 

Computer hardware and software

 

 

113,483

 

 

 

109,703

 

Building and land improvements

 

 

43,319

 

 

 

43,271

 

Furniture and fixtures

 

 

19,506

 

 

 

19,287

 

Land

 

 

3,061

 

 

 

3,073

 

     Total property, plant and equipment

 

 

365,399

 

 

 

359,585

 

Less: accumulated depreciation and amortization

 

 

(241,550

)

 

 

(235,201

)

     Total property, plant and equipment, net

 

$

123,849

 

 

$

124,384

 

Long-lived assets used in operations are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and the undiscounted cash flows estimated to be generated by the asset are less than the asset’s carrying value.

Depreciation expense was $8.1 million and $6.9 million for the three months ended March 31, 2026 and 2025, respectively, which is recorded in cost of revenue, selling, general and administrative expenses and research and development expenses in the Condensed Consolidated Statements of Loss.

Assets Held For Sale

On December 31, 2025, the Company determined that it continued to meet the held for sale criteria pursuant to ASC 360, "Impairment and Disposal of Long-Live Assets" on a portion of the Company's property located at its Huntsville, Alabama campus and ceased recording depreciation on the assets. The Company continues to assess the probability that the sale of its headquarters in Huntsville will occur and has determined it is probable of occurring in the next twelve months.

The Company records assets held for sale at the lower of their carrying value or fair value. The total carrying value of assets held for sale was $11.9 million as of March 31, 2026 and December 31, 2025, respectively, and is separately recorded on the balance sheet.

v3.26.1
Goodwill
3 Months Ended
Mar. 31, 2026
Goodwill Disclosure [Abstract]  
Goodwill

8. GOODWILL

The changes in the carrying amount of goodwill for the three months ended March 31, 2026 and the twelve months ended December 31, 2025, are as follows:

(In thousands)

 

Services & Support

 

As of December 31, 2024

 

$

52,918

 

Foreign currency translation adjustments

 

 

7,065

 

As of December 31, 2025

 

$

59,983

 

Foreign currency translation adjustments

 

 

(980

)

As of March 31, 2026

 

$

59,003

 

Goodwill represents the excess purchase price over the fair value of net assets acquired. The Company performs its annual goodwill impairment test as of the first day of the fourth quarter. In addition, the Company performs an interim impairment assessment prior to our annual measurement date whenever events or changes in circumstances indicate that the carrying amount of such assets (or group of assets) may not be recoverable.

No impairment of goodwill was recognized during the three months ended March 31, 2026 and 2025. As of March 31, 2026, accumulated goodwill impairment losses totaled $335.3 million.

v3.26.1
Intangible Assets
3 Months Ended
Mar. 31, 2026
Intangible Assets, Net (Excluding Goodwill) [Abstract]  
Intangible Assets

9. INTANGIBLE ASSETS

Intangible assets as of March 31, 2026 and December 31, 2025, consisted of the following:

 

 

 

 

As of March 31, 2026

 

 

As of December 31, 2025

 

(In thousands excluding years)

Weighted Average Useful Life
(in years)

 

 

Gross Carrying Amount

 

 

Accumulated Amortization

 

 

Net Book Value

 

 

Gross Carrying Amount

 

 

Accumulated Amortization

 

 

Net Book Value

 

Customer relationships

 

11.0

 

 

$

55,540

 

 

$

(26,231

)

 

$

29,309

 

 

$

56,244

 

 

$

(25,306

)

 

$

30,938

 

Backlog

 

1.7

 

 

 

60,077

 

 

 

(60,077

)

 

 

 

 

 

61,081

 

 

 

(61,081

)

 

 

 

Developed technology

 

7.4

 

 

 

431,208

 

 

 

(180,675

)

 

 

250,533

 

 

 

429,329

 

 

 

(168,073

)

 

 

261,256

 

Licensed technology

 

9.0

 

 

 

5,900

 

 

 

(5,272

)

 

 

628

 

 

 

5,900

 

 

 

(5,108

)

 

 

792

 

Licensed agreements

 

8.5

 

 

 

560

 

 

 

(456

)

 

 

104

 

 

 

560

 

 

 

(446

)

 

 

114

 

Trade names

 

2.8

 

 

 

31,078

 

 

 

(30,372

)

 

 

706

 

 

 

31,598

 

 

 

(30,651

)

 

 

947

 

     Total

 

 

 

$

584,363

 

 

$

(303,083

)

 

$

281,280

 

 

$

584,712

 

 

$

(290,665

)

 

$

294,047

 

No impairment losses of intangible assets were recorded during the three months ended March 31, 2026 and 2025.

Amortization expense was $16.9 million and $14.9 million in the three months ended March 31, 2026 and 2025, respectively, and was included in cost of revenue, selling, general and administrative expenses and research and development expenses in the Condensed Consolidated Statements of Loss.

During the three months ended March 31, 2026, the Company had development costs of $8.4 million for developed technology assets with a weighted average amortization period of three years with no expected residual value.

Estimated future amortization expense of intangible assets is as follows:

 

 

As of

 

(In thousands)

 

March 31, 2026

 

2026

 

$

52,238

 

2027

 

 

64,630

 

2028

 

 

55,854

 

2029

 

 

47,215

 

2030

 

 

44,627

 

Thereafter

 

 

16,716

 

     Total

 

$

281,280

 

v3.26.1
Credit Agreements
3 Months Ended
Mar. 31, 2026
Debt Disclosure [Abstract]  
Credit Agreements

10. CREDIT AGREEMENTS

The carrying amounts of the Company's non-current revolving credit facility in its Condensed Consolidated Balance Sheets were as follows:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Wells Fargo credit agreement

 

$

25,000

 

 

$

25,000

 

Total non-current revolving credit facility

 

$

25,000

 

 

$

25,000

 

As of March 31, 2026 and December 31, 2025, the estimated fair value of our revolving credit agreement approximates the carrying value. As of March 31, 2026, the weighted average interest rate on our revolving credit agreement was 8.92%.

Revolving Credit Agreement

On July 18, 2022, ADTRAN, Inc., as the borrower ("U.S. Borrower"), and the Company entered into a credit agreement with a syndicate of banks, including Wells Fargo Bank, National Association, as administrative agent (“Administrative Agent”), and the other lenders named therein (the “Original Credit Agreement”), as amended by the First Amendment to Credit Agreement, dated August 9, 2023 (“Amendment No. 1”), the Second Amendment to Credit Agreement, dated January 16, 2024 (“Amendment No. 2”), the Third Amendment to Credit Agreement, dated March 12, 2024 (“Amendment No. 3”), the Fourth Amendment to Credit Amendment, dated June 4, 2024 among Adtran Networks (the "German Borrower") and the parties set forth above ("Amendment No. 4"), the Fifth Amendment to Credit Agreement and Waiver, dated May 6, 2025, among the German Borrower and the parties set forth above (“Amendment No. 5”), and the Sixth Amendment and Consent Credit Agreement, dated September 16, 2025, among the U.S. Borrower,

the German Borrower and the lenders party thereto ("Amendment No. 6"); (the Original Credit Agreement as amended by Amendment No. 1, Amendment No. 2. Amendment No. 3, Amendment No. 4 and Amendment No. 5, the “Existing Credit Agreement”).

As of March 31, 2026, the Amended Credit Agreement provided for a secured revolving credit facility of up to $350.0 million of borrowings, $50.0 million of which is solely available to the German Borrower.

As of March 31, 2026, the Company’s borrowings under the revolving line of credit were $25.0 million. The credit facilities provided under the Amended Credit Agreement mature in July 2027, but the U.S. Borrower may request extensions subject to customary conditions. In addition, the U.S. Borrower may utilize up to $50.0 million of the $350.0 million total revolving facility for the issuance of letters of credit. As of March 31, 2026, the U.S. Borrower had a total of $5.8 million in letters of credit under the Amended Credit Agreement, leaving a net amount (after giving effect to the $25.0 million of outstanding borrowings described above) of $319.2 million available for future borrowings, based on debt covenant compliance metrics. Any future credit extensions under the Amended Credit Agreement are subject to customary conditions precedent. The proceeds of any loans may be used as described above, as well as for working capital and other general corporate purposes.

Moreover, the Amended Credit Agreement provides for a sublimit under the existing $350.0 million revolving commitments in an aggregate amount of $50.0 million (“Subline”), which Subline is available for borrowings by the German Borrower. The Company had no borrowings under the Subline as of March 31, 2026. The existing swing line sublimit and letter of credit sublimit under the Amended Credit Agreement remain available to the U.S. Borrower (and not to the German Borrower). Otherwise, the loans under the Subline are subject to substantially the same terms and conditions under the Amended Credit Agreement (including with respect to the interest rate and maturity date) as the other existing revolving commitments.

v3.26.1
Convertible Senior Notes and Capped Calls
3 Months Ended
Mar. 31, 2026
Debt Disclosure [Abstract]  
Convertible Senior Notes and Capped Calls

11. CONVERTIBLE SENIOR NOTES AND CAPPED CALLS

The outstanding principal and carrying value of the convertible senior notes were as follows:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Convertible senior notes

 

$

201,250

 

 

$

201,250

 

Less: unamortized debt issuance costs

 

 

(7,825

)

 

 

(8,212

)

Non-current convertible senior notes

 

$

193,425

 

 

$

193,038

 

The estimated fair value of the 2030 Notes was $273.9 million and $217.5 million as of March 31, 2026 and December 31, 2025, respectively. The estimated fair value of the 2030 Notes, based on Level 2 inputs of the valuation hierarchy, were determined based on the quoted bid prices of the 2030 Notes in an over-the-counter market on the last trading day of the reporting period.

The effective interest rate of the 2030 Notes over their expected life is 4.7%. The following is a summary of interest expense for the 2030 Notes:

 

 

Three Months Ended

 

(In thousands)

 

March 31, 2026

 

Contractual interest

 

$

1,854

 

Amortization of issuance costs

 

 

387

 

Total interest expense

 

$

2,241

 

On September 19, 2025, the Company issued $201.3 million principal amount of its 3.75% convertible senior notes due September 15, 2030. The 2030 Notes were issued pursuant to, and are governed by, an indenture (the “Indenture”), dated as of September 19, 2025, between the Company and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”). The 2030 Notes are the Company’s senior, unsecured obligations and bear interest at a rate of 3.75% per year payable semi-annually in arrears on March 15 and September 15 of each year, beginning on March 15, 2026. Each $1,000 principal amount of the 2030 Notes will be convertible into 86.8206 shares of the Company’s common stock, which is equivalent to a conversion price of approximately $11.52 per share, subject to adjustment upon the occurrence of specified events. In addition, if certain corporate events that constitute a “make-whole fundamental change” (as defined in the Indenture) occur, then the conversion rate will, in certain circumstances, be increased for a specified period of time.

The 2030 Notes are convertible at the option of the holders of the 2030 Notes before June 15, 2030, only under the following circumstances: (1) during any calendar quarter (and only during such calendar quarter) commencing after the calendar quarter ending on December 31, 2025, if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price for each of at least 20 trading days, whether or not consecutive, during the last 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of the 2030 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; or (4) if the Company calls (or is deemed to have called) the 2030 Notes for redemption. From and after June 15, 2030, noteholders may convert their 2030 Notes at any time at their election until

the close of business on the second scheduled trading day immediately before the maturity date. The Company will settle conversions by paying cash up to the aggregate principal amount of the 2030 Notes to be converted and paying or delivering, as applicable, cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company’s election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted, based on the applicable conversion rate.

The 2030 Notes will be redeemable, in whole or in part (subject to certain limitations described below), at the Company’s option at any time, and from time to time, on or after September 20, 2028 and on or before the 46th scheduled trading day immediately before the maturity date, but only if (i) the Notes are “Freely Tradable” (as defined in the Indenture) as of the date the Company sends the related redemption notice, and all accrued and unpaid additional interest, if any, has been paid in full as of the most recent interest payment date occurring on or before the date the Company sends the related redemption notice; and (ii) the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price on (1) each of at least 20 trading days, whether or not consecutive, during the last 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (2) the trading day immediately before the date the Company sends such redemption notice. However, the Company may not redeem less than all of the outstanding Notes unless at least $70.0 million aggregate principal amount of Notes are outstanding and not called for redemption as of the time the Company sends, and after giving effect to, the related redemption notice. The redemption price will be a cash amount equal to the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. In addition, calling (or the deemed calling of) any Note for redemption will constitute a “make-whole fundamental change” with respect to that Note, in which case the conversion rate applicable to the conversion of that Note will be increased in certain circumstances if it is converted during the related redemption conversion period. No sinking fund is provided for the 2030 Notes, which means the Company is not required to redeem or retire the 2030 Notes periodically.

If certain corporate events that constitute a “fundamental change” (as defined in the Indenture) occur, then, subject to a limited exception for certain cash mergers, noteholders may require the Company to repurchase their Notes at a cash repurchase price equal to the principal amount of the Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. The definition of “fundamental change” includes certain business combination transactions involving the Company and certain de-listing events with respect to the Company’s common stock.

Capped Calls

In connection with the pricing of the 2030 Notes and the exercise of the initial purchasers’ option to purchase additional 2030 Notes, the Company entered into privately negotiated capped call transactions with one of the initial purchasers of the 2030 Notes or its affiliate and certain other financial institutions pursuant to capped call confirmations (collectively, the “Capped Calls”). The premiums paid for the purchases of the Capped Calls were approximately $17.6 million. The Capped Calls have an initial strike price of approximately $11.52 per share, subject to certain adjustments substantially similar to those applicable to the corresponding 2030 Notes. The Capped Calls have an initial cap price of approximately $15.51 per share, subject to certain adjustments. The Capped Calls cover, subject to anti-dilution adjustments, approximately 17.5 million shares of the Company’s common stock.

The Capped Calls are generally expected to reduce potential dilution to the Company’s common stock and/or offset any cash payments that the Company is required to make in excess of the principal amount of any converted 2030 Notes, with such reduction and/or offset subject to a cap, based on the cap price of the Capped Calls.

The Capped Calls are separate transactions and are not part of the terms of the 2030 Notes. The Capped Calls do not meet the criteria for separate accounting as a derivative as they are indexed to the Company's stock and meet the requirements to be classified in equity and, as such, are not remeasured each reporting period.

v3.26.1
Employee Benefit Plans
3 Months Ended
Mar. 31, 2026
Retirement Benefits [Abstract]  
Employee Benefit Plans

12. EMPLOYEE BENEFIT PLANS

Pension Benefit Plan

We maintain a defined benefit pension plan covering employees in certain foreign countries. The net amounts recognized in the Condensed Consolidated Balance Sheets for the unfunded pension liability as of March 31, 2026 and December 31, 2025 were as follows:

 

 

 

 

As of

 

 

As of

 

(In thousands)

 

Balance Sheet Location

 

March 31, 2026

 

 

December 31, 2025

 

Non-current pension asset

 

Other non-current assets

 

$

3,148

 

 

$

2,291

 

Current pension liability

 

Accrued wages and benefits

 

 

(366

)

 

 

(372

)

Non-current pension liability

 

Non-current pension liability

 

 

(6,305

)

 

 

(6,277

)

Net pension liability

 

 

 

$

(3,523

)

 

$

(4,358

)

 

The Company's defined benefit pension liability represents the projected benefit obligation, which is the actuarial present value of the vested benefits to which the employee is currently entitled based on the employee's expected date of retirement.

The following table summarizes the components of net periodic pension cost related to the Company's defined benefit pension plans:

 

 

Three Months Ended

 

 

 

March 31,

 

(In thousands)

 

2026

 

 

2025

 

Service cost

 

$

848

 

 

$

389

 

Interest cost

 

 

366

 

 

 

486

 

Expected return on plan assets

 

 

(521

)

 

 

(588

)

Amortization of actuarial losses

 

 

20

 

 

 

11

 

Net periodic pension cost

 

$

713

 

 

$

298

 

The components of net periodic pension cost, other than the service cost component, are included in other income, net in the Condensed Consolidated Statements of Loss. Service cost is included in cost of revenue, selling, general and administrative expenses and research and development expenses in the Condensed Consolidated Statements of Loss. The Company made contributions to the defined benefit pension plans totaling $1.1 million during the three months ended March 31, 2026 and 2025. Contributions to the defined benefit pension plans for the remainder of 2026 will be limited to benefit payments to retirees which are paid out of the operating cash flows of the Company and are expected to be approximately $1.6 million.

v3.26.1
Equity
3 Months Ended
Mar. 31, 2026
Equity [Abstract]  
Equity

13. EQUITY

Accumulated Other Comprehensive Income

The following tables present the changes in accumulated other comprehensive income, net of tax, by component:

 

 

Three Months Ended March 31, 2026

 

(In thousands)

 

Unrealized
(Losses) Gains
on
Available-
for-Sale
Securities

 

 

Defined
Benefit Plan
Adjustments

 

 

Foreign
Currency Translation
Adjustments

 

 

ASU 2018-02 Adoption

 

 

Total

 

Balance as of December 31, 2025

 

$

(382

)

 

$

3,083

 

 

$

75,791

 

 

$

385

 

 

$

78,877

 

Other comprehensive income (loss) before
   reclassifications

 

 

15

 

 

 

 

 

 

(8,765

)

 

 

 

 

 

(8,750

)

Amounts reclassified from accumulated other
   comprehensive loss

 

 

(15

)

 

 

(66

)

 

 

 

 

 

 

 

 

(81

)

Net current period other comprehensive loss

 

 

 

 

 

(66

)

 

 

(8,765

)

 

 

 

 

 

(8,831

)

Balance as of March 31, 2026

 

$

(382

)

 

$

3,017

 

 

$

67,026

 

 

$

385

 

 

$

70,046

 

 

 

 

Three Months Ended March 31, 2025

 

(In thousands)

 

Unrealized
(Losses)
Gains
on
Available-
for-Sale
Securities

 

 

Defined
Benefit Plan
Adjustments

 

 

Foreign
Currency Translation
Adjustments

 

 

ASU 2018-02 Adoption

 

 

Total

 

Balance as of December 31, 2024

 

$

(382

)

 

$

(1,027

)

 

$

12,278

 

 

$

385

 

 

$

11,254

 

Other comprehensive income before
   reclassifications

 

 

48

 

 

 

 

 

 

20,247

 

 

 

 

 

 

20,295

 

Amounts reclassified from accumulated other
   comprehensive (loss) income

 

 

(48

)

 

 

131

 

 

 

 

 

 

 

 

 

83

 

Net current period other comprehensive income

 

 

 

 

 

131

 

 

 

20,247

 

 

 

 

 

 

20,378

 

Balance as of March 31, 2025

 

$

(382

)

 

$

(896

)

 

$

32,525

 

 

$

385

 

 

$

31,632

 

 

The following tables present the details of reclassifications out of accumulated other comprehensive (loss) income:

 

 

Three Months Ended March 31, 2026

(In thousands)

 

Amount Reclassified from Accumulated
Other Comprehensive Loss

 

 

Affected Line Item

Unrealized gain on available-for-sale securities:

 

 

 

 

 

Net realized loss on sales of securities

 

$

(20

)

 

Net investment loss

Defined benefit plan adjustments – actuarial loss

 

 

(96

)

 

Other (expense) income

Total reclassifications for the period, before tax

 

 

(116

)

 

 

Tax benefit

 

 

35

 

 

 

Total reclassifications for the period, net of tax

 

$

(81

)

 

 

 

 

 

Three Months Ended March 31, 2025

(In thousands)

 

Amount Reclassified from Accumulated Other Comprehensive Income

 

 

Affected Line Item

Unrealized gain on available-for-sale securities:

 

 

 

 

 

Net realized loss on sales of securities

 

$

(65

)

 

Net investment loss

Defined benefit plan adjustments – actuarial gain

 

 

190

 

 

Other (expense) income

Total reclassifications for the period, before tax

 

 

125

 

 

 

Tax expense

 

 

(42

)

 

 

Total reclassifications for the period, net of tax

 

$

83

 

 

 

The following table presents the tax effects related to the change in each component of other comprehensive (loss) income:

 

 

Three Months Ended

 

 

Three Months Ended

 

 

 

March 31, 2026

 

 

March 31, 2025

 

(In thousands)

 

Before-Tax
Amount

 

 

Tax
(Expense)
Benefit

 

 

Net-of-Tax
Amount

 

 

Before-Tax
Amount

 

 

Tax
(Expense)
Benefit

 

 

Net-of-Tax
Amount

 

Unrealized gain (loss) on available-for-sale securities

 

$

20

 

 

$

(5

)

 

 

15

 

 

$

65

 

 

$

(17

)

 

 

48

 

Reclassification adjustment for amounts related to available-for-sale investments included in net loss

 

 

(20

)

 

 

5

 

 

 

(15

)

 

 

(65

)

 

 

17

 

 

 

(48

)

Reclassification adjustment for amounts related to defined benefit plan adjustments included in net (loss) gain

 

 

(96

)

 

 

30

 

 

 

(66

)

 

 

190

 

 

 

(59

)

 

 

131

 

Foreign currency translation adjustments

 

 

(8,765

)

 

 

 

 

 

(8,765

)

 

 

20,247

 

 

 

 

 

 

20,247

 

Total Other Comprehensive (Loss) Income

 

$

(8,861

)

 

$

30

 

 

$

(8,831

)

 

$

20,437

 

 

$

(59

)

 

$

20,378

 

 

 

v3.26.1
Redeemable Non-controlling Interest
3 Months Ended
Mar. 31, 2026
Redeemable Noncontrolling Interest, Equity, Carrying Amount [Abstract]  
Redeemable Non-controlling Interest

14. REDEEMABLE NON-CONTROLLING INTEREST

As of March 31, 2026 and December 31, 2025, the non-controlling Adtran Networks stockholders’ equity ownership percentage in Adtran Networks was approximately 28.8% and 29.2%, respectively.

The following table summarizes the redeemable non-controlling interest activity for the three months ended March 31, 2026 and for the year ended December 31, 2025:

 

 

Three Months Ended

 

 

For the Year Ended

 

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

 

Balance at beginning of period

 

$

373,328

 

 

$

422,943

 

 

Redemption of redeemable non-controlling interest

 

 

(4,311

)

 

 

(49,615

)

 

Net income attributable to redeemable non-controlling interests

 

 

2,251

 

 

 

9,413

 

 

Annual recurring compensation earned

 

 

(2,251

)

 

 

(9,413

)

 

Balance at end of period

 

$

369,017

 

 

$

373,328

 

 

 

Annual recurring compensation payable on untendered outstanding shares under the DPLTA must be recognized as it is accrued. For the three months ended March 31, 2026, we accrued $2.2 million and for the year ended December 31, 2025, the Company accrued $9.3 million, representing the portion of the annual recurring cash compensation to the non-controlling shareholders during such periods. The 2025 Annual Recurring Compensation accrual will be paid after the ordinary general shareholders' meeting of Adtran Networks in 2026. The 2026 Annual Recurring Compensation accrual will be paid after the ordinary general shareholders' meeting of Adtran Networks in 2027.

v3.26.1
Loss Per Share
3 Months Ended
Mar. 31, 2026
Earnings Per Share [Abstract]  
Loss Per Share

15. LOSS PER SHARE

The calculation of basic and diluted loss per share for the quarters ended March 31, 2026 and 2025 are as follows:

 

 

Three Months Ended

 

 

 

 

March 31,

 

 

(In thousands, except per share amounts)

 

2026

 

 

2025

 

 

Numerator

 

 

 

 

 

 

 

Net loss attributable to ADTRAN Holdings, Inc.

 

$

(1,321

)

 

$

(11,267

)

 

Effect of redemption of RNCI

 

 

301

 

 

 

(3

)

 

Net loss attributable to ADTRAN Holdings, Inc. common stockholders

 

$

(1,020

)

 

$

(11,270

)

 

Denominator

 

 

 

 

 

 

 

Weighted average number of shares – basic

 

 

80,321

 

 

 

79,534

 

 

Weighted average number of shares – diluted

 

 

80,321

 

 

 

79,534

 

 

Loss per share attributable to ADTRAN Holdings, Inc. – basic

 

$

(0.01

)

 

$

(0.14

)

 

Loss per share attributable to ADTRAN Holdings, Inc. – diluted

 

$

(0.01

)

 

$

(0.14

)

 

 

 

 

 

 

 

 

 

The following potentially dilutive shares were excluded from the calculation of the diluted weighted average number of shares outstanding as the effect would have been anti-dilutive:

 

 

Three Months Ended

 

 

 

 

March 31,

 

 

(In thousands)

 

2026

 

 

2025

 

 

Convertible senior notes

 

 

2,440

 

 

 

 

 

Stock options

 

 

794

 

 

 

711

 

 

PSUs, RSUs and restricted stock

 

 

446

 

 

 

202

 

 

v3.26.1
Segment Information
3 Months Ended
Mar. 31, 2026
Segment Reporting [Abstract]  
Segment Information

16. SEGMENT INFORMATION

The chief operating decision maker is the Company's Chief Executive Officer who regularly reviews the Company’s financial performance based on two reportable segments: (1) Network Solutions and (2) Services & Support.

The Network Solutions segment includes hardware and software products that enable a digital future which support the Company's Subscriber, Access & Aggregation, and Optical Networking Solutions. The Company's cloud-managed Wi-Fi gateways, virtualization software, and switches provide a mix of wired and wireless connectivity at the customer premises. In addition, its Carrier Ethernet products support a variety of applications at the network edge ranging from mobile backhaul to connecting enterprise customers (“Subscriber Solutions"). The Company's portfolio includes products for multi-gigabit service delivery over fiber or alternative media to homes and businesses.

The Services & Support segment offers a comprehensive portfolio of network design, implementation, maintenance and cloud-hosted services supporting its Subscriber, Access & Aggregation, and Optical Networking Solutions. These services assist operators in the deployment of multi-vendor networks while reducing their cost to maintain these networks. The cloud-hosted services include a suite of SaaS applications under the Company's Mosaic One platform that manages end-to-end network and service optimization for both fiber access infrastructure and mesh Wi-Fi connectivity. The Company backs these services with a global support organization that offers on-site and off-site support services with varying SLAs.

The performance of these segments is evaluated based on revenue, gross profit and gross margin; therefore, selling, general and administrative expenses, research and development expenses, interest and dividend income, interest expense, net investment loss, other income, net and income tax (expense) benefit are reported on a consolidated basis only. There is no inter-segment revenue. Asset information by reportable segment is not produced and, therefore, is not reported.

The following tables present information about the revenue and gross profit of the Company's reportable segments:

 

 

Three Months Ended

 

 

 

March 31, 2026

 

 

March 31, 2025

 

(In thousands)

 

Revenue

 

 

Cost of Revenue

 

 

Gross Profit

 

 

Revenue

 

 

Cost of Revenue

 

 

Gross Profit

 

Network Solutions

 

$

237,941

 

 

$

154,648

 

 

$

83,293

 

 

$

202,217

 

 

$

134,241

 

 

$

67,976

 

Services & Support

 

 

48,145

 

 

 

18,450

 

 

 

29,695

 

 

 

45,527

 

 

 

18,327

 

 

 

27,200

 

Total

 

$

286,086

 

 

$

173,098

 

 

$

112,988

 

 

$

247,744

 

 

$

152,568

 

 

$

95,176

 

For the three months ended March 31, 2026 and 2025, $1.7 million and $1.3 million, respectively, of depreciation expense was included in gross profit for our Network Solutions segment. For the three months ended March 31, 2026 and 2025, less than $0.1 million of depreciation expense was included in gross profit for our Services & Support segment.

Revenue by Geographic Area

The following table presents revenue information by geographic area:

 

 

Three Months Ended

 

 

 

 

March 31,

 

 

(In thousands)

 

2026

 

 

2025

 

 

United States

 

$

146,167

 

 

$

103,189

 

 

United Kingdom

 

 

43,805

 

 

 

62,909

 

 

Germany

 

 

33,925

 

 

 

27,188

 

 

Other international

 

 

62,189

 

 

 

54,458

 

 

Total

 

$

286,086

 

 

$

247,744

 

 

v3.26.1
Commitments and Contingencies
3 Months Ended
Mar. 31, 2026
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies

17. COMMITMENTS AND CONTINGENCIES

Legal Matters

From time to time, the Company is subject to or otherwise involved in various lawsuits, claims, investigations and legal proceedings that arise out of or are incidental to the conduct of our business (collectively, “Legal Matters”), including those relating to employment matters, patent rights, regulatory compliance matters, stockholder claims, and contractual and other commercial disputes. Such Legal Matters, even if not meritorious, could result in the expenditure of significant financial and managerial resources. Additionally, an unfavorable outcome in a legal matter, including in a patent dispute, could require the Company to pay damages, entitle claimants to other relief, such as royalties, or could prevent the Company from selling some of its products in certain jurisdictions. The Company records an accrual for any Legal Matters that arise whenever it considers that it is probable that it is exposed to a loss contingency and the amount of the loss contingency can be reasonably estimated. Although the ultimate disposition of asserted claims cannot be predicted with certainty, it is our belief that the outcome of any such claims, either individually or on a combined basis, will not have a material adverse effect on our consolidated financial position.

As disclosed in Amendment No. 1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on May 20, 2025, we identified errors in our previously issued financial statements related to the historical accounting for certain inventory and cost of goods sold transactions (“Adjustment”). The affected periods included the annual periods ended December 31, 2023 and 2024 and the interim periods ended March 31, 2024, June 30, 2024 and September 30, 2024. In connection with the identification of the Adjustment, the Audit Committee oversaw an internal investigation into the circumstances surrounding the Adjustment and its impact on the Company’s historical financial statements. Based on the findings of the internal investigation, it was determined that the underlying errors giving rise to the Adjustment were not properly addressed in the Company’s previously filed financial statements as of and for the years ended December 31, 2024 and 2023 and were not communicated to the Audit Committee or the independent auditors prior to the filing of the initial Annual Report on Form 10-K for the year ended December 31, 2024. The Company has taken certain remedial actions to address the material weaknesses in its internal controls associated with these findings. On August 4, 2025, the Company received a letter from the Atlanta regional office of the SEC in connection with a non-public, fact-finding inquiry, requesting that we voluntarily provide information regarding the internal investigation. The Company is cooperating in response to the SEC’s inquiry and cannot predict the timing or outcome of the inquiry.

DPLTA Appraisal Proceedings

In addition to such Legal Matters, the Company is a party to appraisal proceedings relating to the DPLTA which were originally filed with the Landgericht Meiningen (Meiningen District Court) on February 3, 2023. The DPLTA provides that Adtran Networks shareholders (other than the Company) be offered, at their election, (i) to put their Adtran Networks shares to the Company in exchange for compensation in cash of €17.21 per share, plus guaranteed interest or (ii) to remain Adtran Networks shareholders and receive recurring cash compensation of €0.52 per share for each full fiscal year of Adtran Networks. The appraisal proceedings, which were initiated by certain minority shareholders of Adtran Networks, challenge the adequacy of both forms of compensation. While the Company believes that the compensation offered in connection with the DPLTA is fair, it notes that German courts often adjudicate increases of the cash compensation to plaintiffs in varying amounts in connection with German appraisal proceedings. Therefore, the Company cannot rule out that the first instance court or an appellate court may increase the cash compensation owed to the minority Adtran Networks shareholders. Given the stage of the appraisal proceedings, the Company is currently unable to predict the likely outcome or estimate the potential financial impact, if any, of the appraisal proceedings. If a ruling were to occur and be upheld upon appeal that required the Company to pay significant additional cash compensation to the Adtran Networks minority shareholders, there exists the possibility of a material adverse effect on our financial position and results of operations for the period in which the ruling occurs or future periods.

DPLTA Exit and Recurring Compensation Costs and the Absorption of Adtran Network's Annual Net Loss

Pursuant to the terms of the DPLTA, each Adtran Networks shareholder (other than the Company) has received an offer to elect either (1) to remain an Adtran Networks shareholder and receive from us an Annual Recurring Compensation payment, or (2) to receive Exit Compensation plus guaranteed interest. The guaranteed interest under the Exit Compensation is calculated from the effective date of the DPLTA to the date the shares are tendered, less any Annual Recurring Compensation paid. The guaranteed interest rate is 5.0% plus a variable component (according to the German Civil Code) that was 1.27% as of March 31, 2026. Assuming all the minority holders of currently outstanding Adtran Networks shares were to elect the second option, the Company would be obligated to make aggregate Exit Compensation payments, including guaranteed interest, of approximately304.4 million or approximately $351.7 million, based on an exchange rate as of March 31, 2026, and reflecting interest accrued through March 31, 2026, during the pendency of the appraisal proceedings discussed below. Shareholders electing the first option of Annual Recurring Compensation may later elect the second option. The opportunity for outside Adtran Networks shareholders to tender Adtran Networks shares in exchange for Exit Compensation had been scheduled to expire on March 16, 2023. However, due to the appraisal proceedings that were initiated in 2023 in accordance with applicable German law, this time period for tendering shares has been extended pursuant to the German Stock Corporation Act (Aktiengesetz) and will end two months after the date on which a final decision in such appraisal proceedings has been published in the Federal Gazette (Bundesanzeiger). Following the court's decision on a procedural matter in the DPLTA appraisal proceedings on July 14, 2025, the proceeding for the trial on the merits of the DPLTA has recommenced. It is expected to take a minimum of 12 months for

a ruling of the court on the merits and such ruling will most likely be appealed, which would be expected to take an additional 12-24 months to be resolved. Accordingly, the Company does not expect a final decision on the DPLTA appraisal proceedings to be rendered and published prior to 2027, and most likely not until 2028 or beyond.

Our obligation to pay Annual Recurring Compensation under the DPLTA is a continuing payment obligation, which will amount to approximately €7.8 million (or $9.0 million based on the current exchange rate) per year assuming none of the minority Adtran Networks shareholders were to elect Exit Compensation. The foregoing amounts do not reflect any potential increase in payment obligations that we may have depending on the outcome of ongoing appraisal proceedings in Germany. The Annual Recurring Compensation is due on the third banking day following the ordinary general shareholders’ meeting of Adtran Networks for the respective preceding fiscal year (but in any event within eight months following expiration of the fiscal year). With respect to the 2025 fiscal year, Adtran Networks’ ordinary general shareholders meeting is scheduled for the second quarter of 2026, and the Annual Recurring Compensation will be due on the third banking day following the meeting. During the three months ended March 31, 2026 and 2025, we accrued $2.2 million and $2.4 million, respectively, in Annual Recurring Compensation, which was reflected as an increase to retained deficit.

For the three months ended March 31, 2026, approximately 0.2 million shares of Adtran Networks stock were tendered to the Company and Exit Compensation of €3.6 million or approximately $4.1 million are to be settled in cash in April 2026. For the three months ended March 31, 2025, less than one thousand shares of Adtran Networks stock were tendered to the Company and exit compensation payments of €12 thousand or $13 thousand based on the applicable exchange rates at the time of the transaction were paid to Adtran Networks shareholders.

In addition, under the DPLTA, subject to certain limitations pursuant to applicable law and the specific terms of the DPLTA, (i) the Company is entitled to issue binding instructions to the management board of Adtran Networks, (ii) Adtran Networks will transfer its annual profit to the Company, subject to, among other things, the creation or dissolution of certain reserves, and (iii) the Company will absorb the annual net loss incurred by Adtran Networks. The Company’s payment obligation in satisfaction of the requirement that it absorb Adtran Networks’ annual net loss applies to the net loss generated by Adtran Networks in 2025 and it will apply to any net loss generated by Adtran Networks in 2026.

Performance Bonds

Certain contracts, customers and jurisdictions in which we do business require us to provide various guarantees of performance such as bid bonds, performance bonds and customs bonds. As of March 31, 2026 and December 31, 2025, we had commitments related to these bonds totaling $22.2 million and $22.4 million, respectively, which expire at various dates through April 2029. In general, we would only be liable for the amount of these guarantees in the event of default under each contract, the probability of which we believe is remote.

Purchase Obligations

The Company purchases components from a variety of suppliers and uses contract manufacturers to provide manufacturing services for our products. Our inventory purchase obligations are for product manufacturing requirements, as well as for commitments to suppliers to secure manufacturing capacity. Certain of our inventory purchase obligations with contract manufacturers and suppliers relate to arrangements to secure supply and pricing for certain product components for multi-year periods. As of March 31, 2026, purchase obligations totaled $223.7 million.

Tariff Refund

On February 20, 2026, the U.S. Supreme Court issued a ruling striking down certain tariffs previously imposed under the International Emergency Economic Powers Act ("IEEPA"). The ultimate availability, timing, and amount of any potential refunds of such tariffs remain highly uncertain and are subject to further legal, regulatory, and administrative developments. Following the Supreme Court’s decision, the U.S. presidential administration announced its intention to invoke other laws to collect tariffs and announced new tariffs on imports from all countries, in addition to any existing non-IEEPA tariffs (including tariffs on semiconductors, which are expected to increase in June 2027).

The Company has concluded that the potential refund of IEEPA tariffs should be evaluated under a loss recovery model pursuant to Accounting Standards Codification ("ASC") 410‑30. The tariffs at issue were previously capitalized to inventory and subsequently expensed through cost of goods sold. Accordingly, any refund represents a recovery of previously recognized costs, and recognition is limited to amounts previously recorded.

Under the loss recovery model, an asset for recovery may be recognized only when receipt is considered probable, as defined under ASC 450‑20. While the Supreme Court ruling establishes a legal basis for recovery, material uncertainty remains regarding the administrative process required to obtain refunds. The U.S. Customs and Border Protection ("CBP") system became operational on April 20, 2026.

Given the lack of clarity surrounding refund execution to determine expected recovery amount, the Company has concluded that recovery of the IEEPA tariffs is not probable as of the reporting date. Accordingly, no refund receivable has been recognized. Management will continue to monitor developments, including CBP implementation milestones, formal guidance on claim submission, and claim acceptance processes.

Additionally, Adtran may owe money to customers depending on final assessments of contractual or implicit passthrough obligations. The Company will continue to monitor developments related to both refund recoverability and customer refund considerations and will update its accounting conclusions in future periods as facts and circumstances evolve.

401(k) Plan Corrective Action

In June 2024, the Company identified that within our Adtran, Inc. 401(k) plan for the year ended 2023, that deferrals and matching contributions should have been applied to vested equity award amounts in accordance with the plan documents. As such, we filed a voluntary correction program (“VCP”) application with the IRS and the Company is still in negotiations with the IRS regarding the appropriate corrective actions for this failure. Nonetheless, based on the current facts and circumstances surrounding the VCP negotiations, the Company accrued $1.4 million during the year ended December 31, 2025.

v3.26.1
Summary of Significant Accounting Policies (Policies)
3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]  
Basis of Presentation

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements of ADTRAN Holdings, Inc. and its subsidiaries have been prepared pursuant to the rules and regulations of the SEC applicable to interim financial information presented in Quarterly Reports on Form 10-Q. Accordingly, certain information and notes required by generally accepted accounting principles in the United States of America (“U.S. GAAP”) for complete financial statements are not included herein. The December 31, 2025, Condensed Consolidated Balance Sheet is derived from audited financial statements but does not include all disclosures required by U.S. GAAP for annual financial statements.

In the opinion of management, all adjustments necessary to fairly state these interim statements have been recorded and are of a normal and recurring nature. The results of operations for an interim period are not necessarily indicative of the results for the full year. The interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in ADTRAN Holdings, Inc. Annual Report on Form 10-K for the year ended December 31, 2025, filed with the SEC on February 26, 2026.

Use of Estimates

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expense during the reporting period. Significant estimates include allowance for credit losses on accounts receivable and contract assets, excess and obsolete inventory reserves, determination and accrual of the deferred revenue related to performance obligations under contracts with customers, estimated costs to complete obligations associated with deferred and accrued revenue and network installations, estimated income tax provision and income tax contingencies, fair value of stock-based compensation, assessment of goodwill and other intangibles for impairment, estimated lives of intangible assets, estimates of intangible assets upon measurement, estimated pension liability and fair value of investments and estimated contingent liabilities. Actual amounts could differ significantly from these estimates.

We assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to us and the unknown future impacts of ongoing inflationary pressures, continued elevated interest rates, instability in the financial services industry, currency fluctuations and political tensions as of March 31, 2026, and through the date of this report. These conditions could result in further impacts to the Company's consolidated financial statements in future reporting periods. The accounting matters assessed included, but were not limited to, the allowance for credit losses, stock-based compensation, carrying value of goodwill, intangibles and other long-lived assets, financial assets, valuation allowances for tax assets, revenue recognition and costs of revenue.

During the three months ended March 31, 2026, there were no other significant changes to our critical accounting policies or estimates from those described in the financial statements contained in the 2025 Form 10-K.

Recent Accounting Pronouncements Not Yet Adopted

Recent Accounting Pronouncements Not Yet Adopted

In September 2025, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2025-06, "Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software," which is intended to modernize the accounting for the costs of internal-use software given the evolution of software development to the incremental and iterative development method. The amendments remove all references to prescriptive and sequential development stages and, instead, require an entity to start capitalizing software costs when management has authorized and committed to funding the software project, and it is probable that the project will be completed and the software will be used to perform the function intended. The amendments are effective for annual reporting periods beginning after December 15, 2027, and interim reporting periods within those annual reporting periods. Early adoption is permitted as of the beginning of an annual reporting period with the amendments to be applied using a prospective, modified or retrospective transition approach. The Company is currently evaluating the impact of adopting this guidance on the consolidated financial statements.

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, as amended by ASU 2025-01, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date", which applies to all public business entities (PBEs) and is intended to enhance disclosures about specific types of expenses included in the expense captions presented on the face of the income statement as well as disclosures about selling expenses. The amendments are effective prospectively for annual periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption and retrospective application are permitted. The Company is currently evaluating the effect that adoption of ASU 2024-03 will have on our disclosures.

Recently Adopted Accounting Pronouncements

Recently Adopted Accounting Pronouncements

There are currently no recently adopted accounting pronouncements that are expected to have a material effect on the Condensed Consolidated Financial Statements.

v3.26.1
Revenue and Receivables (Tables)
3 Months Ended
Mar. 31, 2026
Revenue from Contract with Customer [Abstract]  
Disaggregate of Revenue by Reportable Segment and Revenue Category

The following tables disaggregate revenue by reportable segment and revenue category:

 

 

Three Months Ended

 

 

 

March 31, 2026

 

 

March 31, 2025

 

(In thousands)

 

Network Solutions

 

 

Services & Support

 

 

Total

 

 

Network Solutions

 

 

Services & Support

 

 

Total

 

Subscriber Solutions

 

$

90,193

 

 

$

8,047

 

 

$

98,240

 

 

$

71,748

 

 

$

8,662

 

 

$

80,410

 

Optical Networking Solutions

 

 

70,952

 

 

 

26,374

 

 

 

97,326

 

 

 

54,622

 

 

 

23,576

 

 

 

78,198

 

Access & Aggregation Solutions

 

 

76,796

 

 

 

13,724

 

 

 

90,520

 

 

 

75,847

 

 

 

13,289

 

 

 

89,136

 

Total

 

$

237,941

 

 

$

48,145

 

 

$

286,086

 

 

$

202,217

 

 

$

45,527

 

 

$

247,744

 

Information about Receivable, Contract Assets, and Unearned Revenue from Contracts with Customers

The following table provides information about accounts receivable, contract assets and unearned revenue from contracts with customers:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Accounts receivable, net

 

$

215,473

 

 

$

210,687

 

Contract assets(1)

 

$

533

 

 

$

432

 

Unearned revenue

 

$

90,752

 

 

$

87,541

 

Non-current unearned revenue

 

$

26,227

 

 

$

27,143

 

 

(1) Included in other receivables on the Condensed Consolidated Balance Sheets.

v3.26.1
Stock-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2026
Share-Based Payment Arrangement [Abstract]  
Summary of PSUs, RSUs and Restricted Stock

The following table summarizes the PSUs, RSUs and restricted stock outstanding as of December 31, 2025, and March 31, 2026 and the changes that occurred during the three months ended March 31, 2026:

 

 

Number of
Shares
(in thousands)

 

 

Weighted Avg. Grant Date Fair Value
(per share)

 

Unvested PSUs, RSUs and restricted stock outstanding, December 31, 2025

 

 

1,967

 

 

$

10.70

 

PSUs, RSUs and restricted stock granted

 

 

95

 

 

$

8.88

 

PSUs, RSUs and restricted stock vested

 

 

(487

)

 

$

11.50

 

PSUs, RSUs and restricted stock forfeited

 

 

(59

)

 

$

19.32

 

Unvested PSUs, RSUs and restricted stock outstanding, March 31, 2026

 

 

1,516

 

 

$

9.99

 

v3.26.1
Investments (Tables)
3 Months Ended
Mar. 31, 2026
Investments, Debt and Equity Securities [Abstract]  
Cash Equivalents and Investments held at Fair Value

The Company has cash equivalents and investments which are held at fair value as follows:

 

 

 

 

 

Fair Value Measurements as of March 31, 2026 Using

 

(In thousands)

 

Fair Value

 

 

Quoted Prices
in Active
Market for
Identical
Assets
(Level 1)

 

 

Significant
Other
Observable
Inputs
(Level 2)

 

 

Significant Unobservable Inputs
(Level 3)

 

Cash equivalents

 

 

 

 

 

 

 

 

 

 

 

 

Money market funds (1)

 

$

246

 

 

$

246

 

 

$

 

 

$

 

Marketable equity securities

 

 

 

 

 

 

 

 

 

 

 

 

Marketable equity securities

 

 

937

 

 

 

937

 

 

 

 

 

 

 

Deferred compensation plan assets

 

 

33,813

 

 

 

33,813

 

 

 

 

 

 

 

Total

 

$

34,996

 

 

$

34,996

 

 

$

 

 

$

 

 

 

 

 

 

Fair Value Measurements as of December 31, 2025 Using

 

(In thousands)

Fair Value

 

 

Quoted Prices
in Active
Market for
Identical
Assets
(Level 1)

 

 

Significant
Other
Observable
Inputs
(Level 2)

 

 

Significant Unobservable Inputs
(Level 3)

 

Cash equivalents

 

 

 

 

 

 

 

 

 

 

 

Money market funds (1)

$

245

 

 

$

245

 

 

$

 

 

$

 

Marketable equity securities

 

 

 

 

 

 

 

 

 

 

 

Marketable equity securities

 

1,022

 

 

 

1,022

 

 

 

 

 

 

 

Deferred compensation plan assets

 

35,174

 

 

 

35,174

 

 

 

 

 

 

 

Total

$

36,441

 

 

$

36,441

 

 

$

 

 

$

 


(1) The money market fund balances of $0.2 million as of March 31, 2026 and December 31, 2025, are included in cash and cash equivalents on the balance sheet.

v3.26.1
Inventory (Tables)
3 Months Ended
Mar. 31, 2026
Inventory Disclosure [Abstract]  
Changes in Carrying Amount of Inventory inventory, net was comprised of the following:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Raw materials

 

$

80,069

 

 

$

78,230

 

Work in process

 

 

12,867

 

 

 

12,801

 

Finished goods

 

 

116,067

 

 

 

124,705

 

Total inventory, net

 

$

209,003

 

 

$

215,736

 

v3.26.1
Property, Plant and Equipment (Tables)
3 Months Ended
Mar. 31, 2026
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment

Property, plant and equipment consisted of the following:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Engineering and other equipment

 

$

133,656

 

 

$

131,665

 

Building

 

 

52,374

 

 

 

52,586

 

Computer hardware and software

 

 

113,483

 

 

 

109,703

 

Building and land improvements

 

 

43,319

 

 

 

43,271

 

Furniture and fixtures

 

 

19,506

 

 

 

19,287

 

Land

 

 

3,061

 

 

 

3,073

 

     Total property, plant and equipment

 

 

365,399

 

 

 

359,585

 

Less: accumulated depreciation and amortization

 

 

(241,550

)

 

 

(235,201

)

     Total property, plant and equipment, net

 

$

123,849

 

 

$

124,384

 

v3.26.1
Goodwill (Tables)
3 Months Ended
Mar. 31, 2026
Goodwill Disclosure [Abstract]  
Summary of Changes in Carrying Amount of Goodwill

The changes in the carrying amount of goodwill for the three months ended March 31, 2026 and the twelve months ended December 31, 2025, are as follows:

(In thousands)

 

Services & Support

 

As of December 31, 2024

 

$

52,918

 

Foreign currency translation adjustments

 

 

7,065

 

As of December 31, 2025

 

$

59,983

 

Foreign currency translation adjustments

 

 

(980

)

As of March 31, 2026

 

$

59,003

 

v3.26.1
Intangible Assets (Tables)
3 Months Ended
Mar. 31, 2026
Intangible Assets, Net (Excluding Goodwill) [Abstract]  
Summary of Intangible Assets

Intangible assets as of March 31, 2026 and December 31, 2025, consisted of the following:

 

 

 

 

As of March 31, 2026

 

 

As of December 31, 2025

 

(In thousands excluding years)

Weighted Average Useful Life
(in years)

 

 

Gross Carrying Amount

 

 

Accumulated Amortization

 

 

Net Book Value

 

 

Gross Carrying Amount

 

 

Accumulated Amortization

 

 

Net Book Value

 

Customer relationships

 

11.0

 

 

$

55,540

 

 

$

(26,231

)

 

$

29,309

 

 

$

56,244

 

 

$

(25,306

)

 

$

30,938

 

Backlog

 

1.7

 

 

 

60,077

 

 

 

(60,077

)

 

 

 

 

 

61,081

 

 

 

(61,081

)

 

 

 

Developed technology

 

7.4

 

 

 

431,208

 

 

 

(180,675

)

 

 

250,533

 

 

 

429,329

 

 

 

(168,073

)

 

 

261,256

 

Licensed technology

 

9.0

 

 

 

5,900

 

 

 

(5,272

)

 

 

628

 

 

 

5,900

 

 

 

(5,108

)

 

 

792

 

Licensed agreements

 

8.5

 

 

 

560

 

 

 

(456

)

 

 

104

 

 

 

560

 

 

 

(446

)

 

 

114

 

Trade names

 

2.8

 

 

 

31,078

 

 

 

(30,372

)

 

 

706

 

 

 

31,598

 

 

 

(30,651

)

 

 

947

 

     Total

 

 

 

$

584,363

 

 

$

(303,083

)

 

$

281,280

 

 

$

584,712

 

 

$

(290,665

)

 

$

294,047

 

Estimated Future Amortization Expense Related to Intangible Assets

Estimated future amortization expense of intangible assets is as follows:

 

 

As of

 

(In thousands)

 

March 31, 2026

 

2026

 

$

52,238

 

2027

 

 

64,630

 

2028

 

 

55,854

 

2029

 

 

47,215

 

2030

 

 

44,627

 

Thereafter

 

 

16,716

 

     Total

 

$

281,280

 

v3.26.1
Credit Agreements (Tables)
3 Months Ended
Mar. 31, 2026
Debt Disclosure [Abstract]  
Carrying Amount of Revolving Agreement

The carrying amounts of the Company's non-current revolving credit facility in its Condensed Consolidated Balance Sheets were as follows:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Wells Fargo credit agreement

 

$

25,000

 

 

$

25,000

 

Total non-current revolving credit facility

 

$

25,000

 

 

$

25,000

 

v3.26.1
Convertible Senior Notes and Capped Calls (Tables)
3 Months Ended
Mar. 31, 2026
Debt Disclosure [Abstract]  
Outstanding Principal and Carrying Value of Convertible Senior Notes

The outstanding principal and carrying value of the convertible senior notes were as follows:

 

 

As of

 

 

As of

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

Convertible senior notes

 

$

201,250

 

 

$

201,250

 

Less: unamortized debt issuance costs

 

 

(7,825

)

 

 

(8,212

)

Non-current convertible senior notes

 

$

193,425

 

 

$

193,038

 

Interest Expense for 2030 Notes

The effective interest rate of the 2030 Notes over their expected life is 4.7%. The following is a summary of interest expense for the 2030 Notes:

 

 

Three Months Ended

 

(In thousands)

 

March 31, 2026

 

Contractual interest

 

$

1,854

 

Amortization of issuance costs

 

 

387

 

Total interest expense

 

$

2,241

 

v3.26.1
Employee Benefit Plans (Tables)
3 Months Ended
Mar. 31, 2026
Retirement Benefits [Abstract]  
Summary of Net Amounts Recognized in Consolidated Balance Sheets for the Unfunded Pension Liability The net amounts recognized in the Condensed Consolidated Balance Sheets for the unfunded pension liability as of March 31, 2026 and December 31, 2025 were as follows:

 

 

 

 

As of

 

 

As of

 

(In thousands)

 

Balance Sheet Location

 

March 31, 2026

 

 

December 31, 2025

 

Non-current pension asset

 

Other non-current assets

 

$

3,148

 

 

$

2,291

 

Current pension liability

 

Accrued wages and benefits

 

 

(366

)

 

 

(372

)

Non-current pension liability

 

Non-current pension liability

 

 

(6,305

)

 

 

(6,277

)

Net pension liability

 

 

 

$

(3,523

)

 

$

(4,358

)

 

Schedule of the Components of Net Periodic Pension Cost

The following table summarizes the components of net periodic pension cost related to the Company's defined benefit pension plans:

 

 

Three Months Ended

 

 

 

March 31,

 

(In thousands)

 

2026

 

 

2025

 

Service cost

 

$

848

 

 

$

389

 

Interest cost

 

 

366

 

 

 

486

 

Expected return on plan assets

 

 

(521

)

 

 

(588

)

Amortization of actuarial losses

 

 

20

 

 

 

11

 

Net periodic pension cost

 

$

713

 

 

$

298

 

v3.26.1
Equity (Tables)
3 Months Ended
Mar. 31, 2026
Equity [Abstract]  
Changes in Accumulated Other Comprehensive Income, Net of Tax, by Component

The following tables present the changes in accumulated other comprehensive income, net of tax, by component:

 

 

Three Months Ended March 31, 2026

 

(In thousands)

 

Unrealized
(Losses) Gains
on
Available-
for-Sale
Securities

 

 

Defined
Benefit Plan
Adjustments

 

 

Foreign
Currency Translation
Adjustments

 

 

ASU 2018-02 Adoption

 

 

Total

 

Balance as of December 31, 2025

 

$

(382

)

 

$

3,083

 

 

$

75,791

 

 

$

385

 

 

$

78,877

 

Other comprehensive income (loss) before
   reclassifications

 

 

15

 

 

 

 

 

 

(8,765

)

 

 

 

 

 

(8,750

)

Amounts reclassified from accumulated other
   comprehensive loss

 

 

(15

)

 

 

(66

)

 

 

 

 

 

 

 

 

(81

)

Net current period other comprehensive loss

 

 

 

 

 

(66

)

 

 

(8,765

)

 

 

 

 

 

(8,831

)

Balance as of March 31, 2026

 

$

(382

)

 

$

3,017

 

 

$

67,026

 

 

$

385

 

 

$

70,046

 

 

 

 

Three Months Ended March 31, 2025

 

(In thousands)

 

Unrealized
(Losses)
Gains
on
Available-
for-Sale
Securities

 

 

Defined
Benefit Plan
Adjustments

 

 

Foreign
Currency Translation
Adjustments

 

 

ASU 2018-02 Adoption

 

 

Total

 

Balance as of December 31, 2024

 

$

(382

)

 

$

(1,027

)

 

$

12,278

 

 

$

385

 

 

$

11,254

 

Other comprehensive income before
   reclassifications

 

 

48

 

 

 

 

 

 

20,247

 

 

 

 

 

 

20,295

 

Amounts reclassified from accumulated other
   comprehensive (loss) income

 

 

(48

)

 

 

131

 

 

 

 

 

 

 

 

 

83

 

Net current period other comprehensive income

 

 

 

 

 

131

 

 

 

20,247

 

 

 

 

 

 

20,378

 

Balance as of March 31, 2025

 

$

(382

)

 

$

(896

)

 

$

32,525

 

 

$

385

 

 

$

31,632

 

 

Reclassifications Out of Accumulated Other Comprehensive (Loss) Income

The following tables present the details of reclassifications out of accumulated other comprehensive (loss) income:

 

 

Three Months Ended March 31, 2026

(In thousands)

 

Amount Reclassified from Accumulated
Other Comprehensive Loss

 

 

Affected Line Item

Unrealized gain on available-for-sale securities:

 

 

 

 

 

Net realized loss on sales of securities

 

$

(20

)

 

Net investment loss

Defined benefit plan adjustments – actuarial loss

 

 

(96

)

 

Other (expense) income

Total reclassifications for the period, before tax

 

 

(116

)

 

 

Tax benefit

 

 

35

 

 

 

Total reclassifications for the period, net of tax

 

$

(81

)

 

 

 

 

 

Three Months Ended March 31, 2025

(In thousands)

 

Amount Reclassified from Accumulated Other Comprehensive Income

 

 

Affected Line Item

Unrealized gain on available-for-sale securities:

 

 

 

 

 

Net realized loss on sales of securities

 

$

(65

)

 

Net investment loss

Defined benefit plan adjustments – actuarial gain

 

 

190

 

 

Other (expense) income

Total reclassifications for the period, before tax

 

 

125

 

 

 

Tax expense

 

 

(42

)

 

 

Total reclassifications for the period, net of tax

 

$

83

 

 

 

Tax Effects Related to the Change in Each Component of Other Comprehensive (Loss) Income

The following table presents the tax effects related to the change in each component of other comprehensive (loss) income:

 

 

Three Months Ended

 

 

Three Months Ended

 

 

 

March 31, 2026

 

 

March 31, 2025

 

(In thousands)

 

Before-Tax
Amount

 

 

Tax
(Expense)
Benefit

 

 

Net-of-Tax
Amount

 

 

Before-Tax
Amount

 

 

Tax
(Expense)
Benefit

 

 

Net-of-Tax
Amount

 

Unrealized gain (loss) on available-for-sale securities

 

$

20

 

 

$

(5

)

 

 

15

 

 

$

65

 

 

$

(17

)

 

 

48

 

Reclassification adjustment for amounts related to available-for-sale investments included in net loss

 

 

(20

)

 

 

5

 

 

 

(15

)

 

 

(65

)

 

 

17

 

 

 

(48

)

Reclassification adjustment for amounts related to defined benefit plan adjustments included in net (loss) gain

 

 

(96

)

 

 

30

 

 

 

(66

)

 

 

190

 

 

 

(59

)

 

 

131

 

Foreign currency translation adjustments

 

 

(8,765

)

 

 

 

 

 

(8,765

)

 

 

20,247

 

 

 

 

 

 

20,247

 

Total Other Comprehensive (Loss) Income

 

$

(8,861

)

 

$

30

 

 

$

(8,831

)

 

$

20,437

 

 

$

(59

)

 

$

20,378

 

 

 

v3.26.1
Redeemable Non-controlling Interest (Tables)
3 Months Ended
Mar. 31, 2026
Redeemable Noncontrolling Interest, Equity, Carrying Amount [Abstract]  
Summary of Redeemable Non-controlling Interest Activity

The following table summarizes the redeemable non-controlling interest activity for the three months ended March 31, 2026 and for the year ended December 31, 2025:

 

 

Three Months Ended

 

 

For the Year Ended

 

 

(In thousands)

 

March 31, 2026

 

 

December 31, 2025

 

 

Balance at beginning of period

 

$

373,328

 

 

$

422,943

 

 

Redemption of redeemable non-controlling interest

 

 

(4,311

)

 

 

(49,615

)

 

Net income attributable to redeemable non-controlling interests

 

 

2,251

 

 

 

9,413

 

 

Annual recurring compensation earned

 

 

(2,251

)

 

 

(9,413

)

 

Balance at end of period

 

$

369,017

 

 

$

373,328

 

 

 

v3.26.1
Loss Per Share (Tables)
3 Months Ended
Mar. 31, 2026
Earnings Per Share [Abstract]  
Summary of Calculation of Basic and Diluted Loss Per Share

The calculation of basic and diluted loss per share for the quarters ended March 31, 2026 and 2025 are as follows:

 

 

Three Months Ended

 

 

 

 

March 31,

 

 

(In thousands, except per share amounts)

 

2026

 

 

2025

 

 

Numerator

 

 

 

 

 

 

 

Net loss attributable to ADTRAN Holdings, Inc.

 

$

(1,321

)

 

$

(11,267

)

 

Effect of redemption of RNCI

 

 

301

 

 

 

(3

)

 

Net loss attributable to ADTRAN Holdings, Inc. common stockholders

 

$

(1,020

)

 

$

(11,270

)

 

Denominator

 

 

 

 

 

 

 

Weighted average number of shares – basic

 

 

80,321

 

 

 

79,534

 

 

Weighted average number of shares – diluted

 

 

80,321

 

 

 

79,534

 

 

Loss per share attributable to ADTRAN Holdings, Inc. – basic

 

$

(0.01

)

 

$

(0.14

)

 

Loss per share attributable to ADTRAN Holdings, Inc. – diluted

 

$

(0.01

)

 

$

(0.14

)

 

 

 

 

 

 

 

 

 

Schedule of Antidilutive Securities Excluded from Earnings Per Share Computation

The following potentially dilutive shares were excluded from the calculation of the diluted weighted average number of shares outstanding as the effect would have been anti-dilutive:

 

 

Three Months Ended

 

 

 

 

March 31,

 

 

(In thousands)

 

2026

 

 

2025

 

 

Convertible senior notes

 

 

2,440

 

 

 

 

 

Stock options

 

 

794

 

 

 

711

 

 

PSUs, RSUs and restricted stock

 

 

446

 

 

 

202

 

 

v3.26.1
Segment Information (Tables)
3 Months Ended
Mar. 31, 2026
Segment Reporting [Abstract]  
Revenue and Gross Profit of Reportable Segments

The following tables present information about the revenue and gross profit of the Company's reportable segments:

 

 

Three Months Ended

 

 

 

March 31, 2026

 

 

March 31, 2025

 

(In thousands)

 

Revenue

 

 

Cost of Revenue

 

 

Gross Profit

 

 

Revenue

 

 

Cost of Revenue

 

 

Gross Profit

 

Network Solutions

 

$

237,941

 

 

$

154,648

 

 

$

83,293

 

 

$

202,217

 

 

$

134,241

 

 

$

67,976

 

Services & Support

 

 

48,145

 

 

 

18,450

 

 

 

29,695

 

 

 

45,527

 

 

 

18,327

 

 

 

27,200

 

Total

 

$

286,086

 

 

$

173,098

 

 

$

112,988

 

 

$

247,744

 

 

$

152,568

 

 

$

95,176

 

Revenue Information by Geographic Area

The following table presents revenue information by geographic area:

 

 

Three Months Ended

 

 

 

 

March 31,

 

 

(In thousands)

 

2026

 

 

2025

 

 

United States

 

$

146,167

 

 

$

103,189

 

 

United Kingdom

 

 

43,805

 

 

 

62,909

 

 

Germany

 

 

33,925

 

 

 

27,188

 

 

Other international

 

 

62,189

 

 

 

54,458

 

 

Total

 

$

286,086

 

 

$

247,744

 

 

v3.26.1
Summary of Significant Accounting Policies - Additional Information (Detail)
€ in Thousands, $ in Thousands
1 Months Ended 3 Months Ended
Sep. 19, 2025
USD ($)
Apr. 30, 2026
USD ($)
Apr. 30, 2026
EUR (€)
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2026
EUR (€)
shares
Mar. 31, 2025
USD ($)
shares
Mar. 31, 2025
EUR (€)
shares
Mar. 31, 2026
EUR (€)
Dec. 31, 2025
USD ($)
Oct. 18, 2022
shares
Summary Of Significant Accounting Policy [Line Items]                    
Percentage of guaranteed interest rate       5.00%       5.00%    
Percentage of guaranteed interest rate plus a variable component       1.27%       1.27%    
Aggregate exit compensation payments obligation including guaranteed interest       $ 351,700       € 304,400    
Expire date of exit compensation       Mar. 16, 2023 Mar. 16, 2023          
Annual recurring compensation obligation       $ 9,000 € 7,800 $ 9,000 € 7,800      
Accrued annual recurring compensation obligation       $ 2,200   $ 2,400        
Number of shares tendered | shares       200,000 200,000          
Cash and cash equivalents       $ 88,270         $ 95,696  
3.75% Convertible Senior Notes Due 2030 [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Principal amount of long term debt $ 201,300                  
Debt instrument, interest rate, stated percentage 3.75%                  
Debt instrument, maturity date Sep. 15, 2030                  
Net proceeds $ 192,600                  
Wells Fargo Credit Agreement [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Net leverage ratio           0.0325 0.0325      
Wells Fargo Credit Agreement [Member] | Acorn HoldCo, Inc., [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Available for future borrowings       319,200            
Wells Fargo Credit Agreement Amendment [Member] | Credit Parties [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Cash and cash equivalents       50,000            
Wells Fargo Credit Agreement Amendment [Member] | Company and Subsidiaries [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Cash and cash equivalents       $ 70,000            
Maximum [Member] | Wells Fargo Credit Agreement [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Net leverage ratio           0.05 0.05      
Maximum [Member] | Wells Fargo Credit Agreement [Member] | First Quarter Ending Springing Covenant Period [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Net leverage ratio       0.04 0.04          
Minimum [Member] | Wells Fargo Credit Agreement [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Fixed charge coverage ratio           0.0125 0.0125      
Minimum [Member] | Wells Fargo Credit Agreement [Member] | Third And Fourth Quarters Ending Springing Covenant Event [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Net leverage ratio           0.035 0.035      
Adtran Networks [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Number of shares tendered | shares       200,000 200,000          
Exit compensation payments           $ 13 € 12      
Adtran Networks [Member] | Subsequent Event [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Exit compensation payments   $ 4,100 € 3,600              
Adtran Networks [Member] | Maximum [Member]                    
Summary Of Significant Accounting Policy [Line Items]                    
Number of additional shares authorized to purchase | shares                   15,346,544
Number of shares tendered | shares       1,000 1,000 1,000 1,000      
v3.26.1
Revenue and Receivables - Additional Information (Detail)
3 Months Ended 12 Months Ended
Mar. 31, 2026
USD ($)
Category
Mar. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2025
USD ($)
Jul. 01, 2024
USD ($)
Revenue [Line Items]          
Number of categories | Category 3        
Accounts receivable, allowance for credit losses $ 1,652,000     $ 1,318,000  
Allowance for credit losses related to contract assets 0 $ 0      
Recognized revenue 23,100,000 21,900,000 $ 52,700,000    
Factor [Member] | Purchase Agreement [Member]          
Revenue [Line Items]          
Accounts receivable 26,100,000 11,200,000      
Secured revolving credit facility amount         $ 40,000,000
Cash proceeds from factoring agreement 51,800,000 31,800,000      
Factor [Member] | Purchase Agreement [Member] | Interest Expense [Member]          
Revenue [Line Items]          
Cost of receivables 500,000 300,000      
Factor [Member] | Purchase Agreement [Member] | Other Assets [Member]          
Revenue [Line Items]          
Accounts receivable gross 3,900,000 $ 3,700,000      
Non-cancellable Contractual Maintenance Agreements Contractual Saas and Subscription Services and Hardware Orders [Member]          
Revenue [Line Items]          
Remaining performance obligations $ 159,200        
Non-cancellable Contractual Maintenance Agreements Contractual Saas and Subscription Services and Hardware Orders [Member] | Minimum [Member]          
Revenue [Line Items]          
Revenue performance obligation, expected timing of satisfaction period 1 year        
Non-cancellable Contractual Maintenance Agreements Contractual Saas and Subscription Services and Hardware Orders [Member] | Maximum [Member]          
Revenue [Line Items]          
Revenue performance obligation, expected timing of satisfaction period 3 years        
v3.26.1
Revenue and Receivables - Disaggregate of Revenue by Reportable Segment and Revenue Category (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Disaggregation Of Revenue [Line Items]    
Revenue $ 286,086 $ 247,744
Subscriber Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 98,240 80,410
Optical Networking Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 97,326 78,198
Access & Aggregation Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 90,520 89,136
Network Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 237,941 202,217
Network Solutions [Member] | Subscriber Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 90,193 71,748
Network Solutions [Member] | Optical Networking Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 70,952 54,622
Network Solutions [Member] | Access & Aggregation Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 76,796 75,847
Services & Support [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 48,145 45,527
Services & Support [Member] | Subscriber Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 8,047 8,662
Services & Support [Member] | Optical Networking Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue 26,374 23,576
Services & Support [Member] | Access & Aggregation Solutions [Member]    
Disaggregation Of Revenue [Line Items]    
Revenue $ 13,724 $ 13,289
v3.26.1
Revenue and Receivables - Information about Receivable, Contract Assets, and Unearned Revenue from Contracts with Customers (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Revenue from Contract with Customer [Abstract]    
Accounts receivable, net $ 215,473 $ 210,687
Contract assets [1] 533 432
Unearned revenue 90,752 87,541
Non-current unearned revenue $ 26,227 $ 27,143
[1] Included in other receivables on the Condensed Consolidated Balance Sheets.
v3.26.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Income Tax Disclosure [Line Items]    
Effective tax rate expense (benefit) 67.30% 4.20%
Deferred tax assets $ 113.9  
Valuation allowance established against deferred tax assets $ 124.5  
v3.26.1
Stock-Based Compensation (Stock Incentive Plans and Stock Options) - Additional Information (Detail) - USD ($)
shares in Millions, $ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]    
Stock-based compensation expense $ 1.8 $ 3.2
Shares available for issuance 5.5  
v3.26.1
Stock-Based Compensation - Summary of PSUs, RSUs and Restricted Stock (Detail)
shares in Thousands
3 Months Ended
Mar. 31, 2026
$ / shares
shares
Share-Based Payment Arrangement [Abstract]  
Number of Shares, Unvested PSUs, RSUs and restricted stock outstanding, beginning balance | shares 1,967
Number of Shares, PSUs, RSUs and restricted stock granted | shares 95
Number of Shares, PSUs, RSUs and restricted stock vested | shares (487)
Number of Shares, PSUs, RSUs and restricted stock forfeited | shares (59)
Number of Shares, Unvested PSUs, RSUs and restricted stock outstanding, ending balance | shares 1,516
Weighted Avg. Grant Date Fair Value, Unvested PSUs, RSUs and restricted stock outstanding, Beginning Balance | $ / shares $ 10.7
Weighted Avg. Grant Date Fair Value, PSUs, RSUs and restricted stock granted | $ / shares 8.88
Weighted Avg. Grant Date Fair Value, PSUs, RSUs and restricted stock vested | $ / shares 11.5
Weighted Avg. Grant Date Fair Value, PSUs, RSUs and restricted stock forfeited | $ / shares 19.32
Weighted Avg. Grant Date Fair Value, Unvested PSUs, RSUs and restricted stock outstanding, Ending Balance | $ / shares $ 9.99
v3.26.1
Stock-Based Compensation (PSUs, RSUs and Restricted Stock) - Additional Information (Detail) - Market-Based PSUs, RSUs and Restricted Stock [Member]
$ in Millions
3 Months Ended
Mar. 31, 2026
USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Unrecognized compensation expense related to other than options $ 12.1
Recognition period of unvested compensation expense 2 years 2 months 12 days
v3.26.1
Investments - Cash Equivalents and Investments held at Fair Value (Detail) - Fair Value, Measurements [Member] - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Schedule of Available-for-sale Securities [Line Items]    
Total $ 34,996 $ 36,441
Quoted Prices in Active Market for Identical Assets (Level 1) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Total 34,996 36,441
Money Market Funds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Cash equivalents 246 245
Money Market Funds [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Cash equivalents 246 245
Marketable Equity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Marketable equity securities 937 1,022
Marketable Equity Securities [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Marketable equity securities 937 1,022
Deferred Compensation Plan Assets [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Marketable equity securities 33,813 35,174
Deferred Compensation Plan Assets [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Marketable equity securities $ 33,813 $ 35,174
v3.26.1
Investments - Cash Equivalents and Investments held at Fair Value (Parenthetical) (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]    
Cash and cash equivalents $ 88,270 $ 95,696
Money Market Funds [Member]    
Debt Securities, Available-for-Sale [Line Items]    
Cash and cash equivalents $ 200 $ 200
v3.26.1
Inventory - Changes in Carrying Amount of Inventory (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Inventory Disclosure [Abstract]    
Raw materials $ 80,069 $ 78,230
Work in process 12,867 12,801
Finished goods 116,067 124,705
Total Inventory, net $ 209,003 $ 215,736
v3.26.1
Property, Plant and Equipment - Property, Plant and Equipment (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Property, Plant and Equipment [Abstract]    
Engineering and other equipment $ 133,656 $ 131,665
Building 52,374 52,586
Computer hardware and software 113,483 109,703
Building and land improvements 43,319 43,271
Furniture and fixtures 19,506 19,287
Land 3,061 3,073
Total property, plant and equipment 365,399 359,585
Less: accumulated depreciation and amortization (241,550) (235,201)
Total property, plant and equipment, net $ 123,849 $ 124,384
v3.26.1
Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Property, Plant and Equipment [Line Items]      
Depreciation expense $ 8,100 $ 6,900  
Expected disposal period 12 months    
Total carrying value of assets held for sale $ 11,901   $ 11,901
v3.26.1
Goodwill - Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Goodwill [Line Items]    
Goodwill, Beginning balance $ 59,983  
Goodwill, Ending balance 59,003 $ 59,983
Services & Support [Member]    
Goodwill [Line Items]    
Goodwill, Beginning balance 59,983 52,918
Foreign currency translation adjustments (980) 7,065
Goodwill, Ending balance $ 59,003 $ 59,983
v3.26.1
Goodwill - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Goodwill [Line Items]    
Impairment charges related to goodwill $ 0 $ 0
Accumulated goodwill impairment losses $ 335,300,000  
v3.26.1
Intangible Assets - Summary of Intangible Assets (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Finite Lived Intangible Assets [Line Items]    
Gross Carrying Amount $ 584,363 $ 584,712
Accumulated Amortization (303,083) (290,665)
Net Book Value $ 281,280 294,047
Developed Technology [Member]    
Finite Lived Intangible Assets [Line Items]    
Weighted Average Useful Life (in years) 7 years 4 months 24 days  
Gross Carrying Amount $ 431,208 429,329
Accumulated Amortization (180,675) (168,073)
Net Book Value $ 250,533 261,256
Customer Relationships [Member]    
Finite Lived Intangible Assets [Line Items]    
Weighted Average Useful Life (in years) 11 years  
Gross Carrying Amount $ 55,540 56,244
Accumulated Amortization (26,231) (25,306)
Net Book Value $ 29,309 30,938
Trade Names [Member]    
Finite Lived Intangible Assets [Line Items]    
Weighted Average Useful Life (in years) 2 years 9 months 18 days  
Gross Carrying Amount $ 31,078 31,598
Accumulated Amortization (30,372) (30,651)
Net Book Value $ 706 947
Backlog [Member]    
Finite Lived Intangible Assets [Line Items]    
Weighted Average Useful Life (in years) 1 year 8 months 12 days  
Gross Carrying Amount $ 60,077 61,081
Accumulated Amortization (60,077) (61,081)
Net Book Value $ 0 0
Licensed Technology [Member]    
Finite Lived Intangible Assets [Line Items]    
Weighted Average Useful Life (in years) 9 years  
Gross Carrying Amount $ 5,900 5,900
Accumulated Amortization (5,272) (5,108)
Net Book Value $ 628 792
Licensed Agreements [Member]    
Finite Lived Intangible Assets [Line Items]    
Weighted Average Useful Life (in years) 8 years 6 months  
Gross Carrying Amount $ 560 560
Accumulated Amortization (456) (446)
Net Book Value $ 104 $ 114
v3.26.1
Intangible Assets - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Finite-Lived Intangible Assets [Line Items]    
Impairment losses of intangible assets $ 0 $ 0
Amortization expense 16,900,000 $ 14,900,000
Developed Technology [Member]    
Finite-Lived Intangible Assets [Line Items]    
Finite-Lived Intangible Assets Acquired $ 8,400  
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life 3 years  
Acquired Finite-Lived Intangible Asset, Residual Value $ 0  
v3.26.1
Intangible Assets - Estimated Future Amortization Expense Related to Intangible Assets (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]    
2026 $ 52,238  
2027 64,630  
2028 55,854  
2029 47,215  
2030 44,627  
Thereafter 16,716  
Net Book Value $ 281,280 $ 294,047
v3.26.1
Credit Agreements - Carrying Amount of Revolving Agreements (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Line of Credit Facility [Line Items]    
Total non-current revolving credit facility $ 25,000 $ 25,000
Wells Fargo Credit Agreement [Member]    
Line of Credit Facility [Line Items]    
Total non-current revolving credit facility $ 25,000 $ 25,000
v3.26.1
Credit Agreements - Additional Information (Detail)
3 Months Ended
Jun. 04, 2024
USD ($)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
Dec. 31, 2025
USD ($)
Line Of Credit Facility [Line Items]        
Weighted average interest rate   8.92%    
Revolving line of credit   $ 25,000,000   $ 25,000,000
Cash and cash equivalents   88,270,000   95,696,000
Wells Fargo Credit Agreement [Member]        
Line Of Credit Facility [Line Items]        
Revolving line of credit   25,000,000   $ 25,000,000
Net leverage ratio     0.0325  
Wells Fargo Credit Agreement [Member] | Maximum [Member]        
Line Of Credit Facility [Line Items]        
Net leverage ratio     0.05  
Wells Fargo Credit Agreement [Member] | Minimum [Member]        
Line Of Credit Facility [Line Items]        
Fixed charge coverage ratio     0.0125  
Wells Fargo Credit Agreement German Borrower [Member]        
Line Of Credit Facility [Line Items]        
Secured revolving credit facility amount   350,000,000    
Acorn HoldCo, Inc., [Member] | Wells Fargo Credit Agreement [Member]        
Line Of Credit Facility [Line Items]        
Secured revolving credit facility amount $ 350,000,000 350,000,000    
Revolving line of credit   25,000,000    
Credit facility, average outstanding amount $ 50,000,000      
Letters of credit may be utilize   50,000,000    
Available for future borrowings   319,200,000    
Acorn HoldCo, Inc., [Member] | Wells Fargo Credit Agreement - Subline [Member]        
Line Of Credit Facility [Line Items]        
Credit facility, average outstanding amount   5,800,000    
Acorn HoldCo, Inc., [Member] | Wells Fargo Credit Agreement - US Borrower [Member]        
Line Of Credit Facility [Line Items]        
Revolving line of credit   25,000,000    
Acorn HoldCo, Inc., [Member] | Wells Fargo Credit Agreement German Borrower [Member]        
Line Of Credit Facility [Line Items]        
Credit facility, average outstanding amount   $ 50,000,000    
First Quarter Ending Springing Covenant Period [Member] | Wells Fargo Credit Agreement [Member] | Maximum [Member]        
Line Of Credit Facility [Line Items]        
Net leverage ratio   0.04    
Third and Fourth Quarters Ending Springing Covenant Event [Member] | Wells Fargo Credit Agreement [Member] | Minimum [Member]        
Line Of Credit Facility [Line Items]        
Net leverage ratio     0.035  
v3.26.1
Credit Agreements - Additional Information (Detail1) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Line of Credit Facility [Line Items]    
Cash and cash equivalents $ 88,270 $ 95,696
Wells Fargo Credit Agreement Amendment [Member] | Credit Parties [Member]    
Line of Credit Facility [Line Items]    
Cash and cash equivalents 50,000  
Wells Fargo Credit Agreement Amendment [Member] | Company and Subsidiaries [Member]    
Line of Credit Facility [Line Items]    
Cash and cash equivalents $ 70,000  
v3.26.1
Convertible Senior Notes and Capped Calls - Outstanding Principal and Carrying Value of Convertible Senior Notes (Details) - Convertible Senior Notes [Member] - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Debt Instrument [Line Items]    
Convertible senior notes $ 201,250 $ 201,250
Less: unamortized debt issuance costs (7,825) (8,212)
Non-current convertible senior notes $ 193,425 $ 193,038
v3.26.1
Convertible Senior Notes and Capped Calls - Additional Information (Details)
shares in Millions
3 Months Ended
Sep. 19, 2025
USD ($)
Days
$ / shares
shares
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
2030 Notes [Member]      
Debt Instrument [Line Items]      
Long-term debt, fair value   $ 273,900,000 $ 217,500,000
Effective interest rate of debt instrument   4.70%  
3.75% Convertible Senior Notes Due 2030 [Member]      
Debt Instrument [Line Items]      
Principal amount of long term debt $ 201,300,000    
Debt instrument, interest rate, stated percentage 3.75%    
Debt instrument, maturity date Sep. 15, 2030    
Debt instrument, payment terms   The 2030 Notes are the Company’s senior, unsecured obligations and bear interest at a rate of 3.75% per year payable semi-annually in arrears on March 15 and September 15 of each year, beginning on March 15, 2026.  
Principal amount of each convertible note $ 1,000    
Debt instrument, conversion ratio 86.8206    
Common stock conversion price | $ / shares $ 11.52    
Conversion price threshold 130.00%    
Number of trading days required for conversion price threshold | Days 20    
Number of consecutive days required for trading days for conversion price threshold | Days 30    
Number of consecutive business days for conversion price threshold | Days 5    
Number of consecutive trading days for conversion price threshold | Days 10    
Principal amount portion for trading price threshold $ 1,000    
Trading price threshold per principal amount portion 98.00%    
Convertible, minimum aggregate principal outstanding $ 70,000,000    
Purchases of capped calls related to convertible senior notes $ 17,600,000    
Strike price | $ / shares 11.52    
Initial cap prices | $ / shares 15.51    
Common stock shares covered under capped call transactions | shares 17.5    
v3.26.1
Convertible Senior Notes and Capped Calls - Interest Expense for 2030 Notes (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Debt Instrument [Line Items]    
Contractual interest $ 4,241 $ 4,761
2030 Notes [Member]    
Debt Instrument [Line Items]    
Contractual interest 1,854  
Amortization of debt issuance cost 387  
Total interest expense $ 2,241  
v3.26.1
Employee Benefit Plans - Summary of Net Amounts Recognized in Consolidated Balance Sheets for the Unfunded Pension Liability (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Defined Benefit Plan Disclosure [Line Items]    
Non-current pension liability $ (6,305) $ (6,277)
Net pension liability (3,523) (4,358)
Other Non-Current Assets [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Non-current pension asset 3,148 2,291
Accrued wages and benefits [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Current pension liability $ (366) $ (372)
v3.26.1
Employee Benefit Plans - Schedule of the Components of Net Periodic Pension Cost (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]    
Service cost $ 848 $ 389
Interest cost $ 366 $ 486
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Other Nonoperating Income (Expense) Other Nonoperating Income (Expense)
Expected return on plan assets $ (521) $ (588)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other Nonoperating Income (Expense) Other Nonoperating Income (Expense)
Amortization of actuarial losses $ 20 $ 11
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other Nonoperating Income (Expense) Other Nonoperating Income (Expense)
Net periodic benefit cost $ 713 $ 298
v3.26.1
Employee Benefit Plans - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Defined Benefit Plan Disclosure [Line Items]    
Contributions to defined benefit pension plans $ 1.1 $ 1.1
Defined benefit pension plans for the remainder of fiscal year $ 1.6  
v3.26.1
Equity - Changes in Accumulated Other Comprehensive Income, Net of Tax, by Component (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance $ 145,830 $ 126,951
Other comprehensive income (loss) before reclassifications (8,750) 20,295
Amounts reclassified from accumulated other comprehensive (loss) income (81) 83
Net current period other comprehensive (loss) income (8,831) 20,378
Ending Balance 137,525 138,893
ASU 2018-02 [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 385 385
Ending Balance 385 385
Accumulated Other Comprehensive Income (Loss) [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 78,877 11,254
Net current period other comprehensive (loss) income (8,831) 20,378
Ending Balance 70,046 31,632
Unrealized Gain on Available-for-Sale Securities [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance (382) (382)
Other comprehensive income (loss) before reclassifications 15 48
Amounts reclassified from accumulated other comprehensive (loss) income (15) (48)
Ending Balance (382) (382)
Defined Benefit Plan Adjustments [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 3,083 (1,027)
Amounts reclassified from accumulated other comprehensive (loss) income (66) 131
Net current period other comprehensive (loss) income (66) 131
Ending Balance 3,017 (896)
Foreign Currency Adjustments [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 75,791 12,278
Other comprehensive income (loss) before reclassifications (8,765) 20,247
Net current period other comprehensive (loss) income (8,765) 20,247
Ending Balance $ 67,026 $ 32,525
v3.26.1
Equity - Reclassifications Out of Accumulated Other Comprehensive (loss) Income (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Reclassification Adjustment Out of Accumulated Other Comprehensive (Loss) Income [Line Items]    
Income (Loss) Before Income Taxes $ 2,847 $ (9,345)
Tax benefit (1,917) 397
Net Loss attributable to ADTRAN Holdings, Inc. (1,321) (11,267)
Reclassification Out of Accumulated Other Comprehensive (Loss) Income [Member]    
Reclassification Adjustment Out of Accumulated Other Comprehensive (Loss) Income [Line Items]    
Defined benefit plan adjustments - actuarial loss (96) 190
Income (Loss) Before Income Taxes (116) 125
Tax benefit 35 (42)
Net Loss attributable to ADTRAN Holdings, Inc. (81) 83
Reclassification Out of Accumulated Other Comprehensive (Loss) Income [Member] | Unrealized Gain on Available-for-Sale Securities [Member]    
Reclassification Adjustment Out of Accumulated Other Comprehensive (Loss) Income [Line Items]    
Net realized loss on sales of securities $ (20) $ (65)
v3.26.1
Equity - Tax Effects Related to the Change in Each Component of Other Comprehensive (Loss) Income (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Equity [Abstract]    
Unrealized gain (loss) on available-for-sale securities, Before-Tax Amount $ 20 $ 65
Unrealized gain (loss) on available-for-sale securities, Tax (Expense) Benefit (5) (17)
Unrealized gain (loss) on available-for-sale securities, Net-of-Tax Amount 15 48
Reclassification adjustment for amounts related to available-for-sale investments included in net loss, Before-Tax Amount (20) (65)
Reclassification adjustment for amounts related to available-for-sale investments included in net (loss) gain, Tax (Expense) Benefit 5 17
Reclassification adjustment for amounts related to available-for-sale investments included in net loss, Net-of-Tax Amount (15) (48)
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net (loss) gain, Before-Tax Amount (96) 190
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net (loss) gain, Tax (Expense) Benefit 30 (59)
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net (loss) gain, Net-of-Tax Amount (66) 131
Foreign currency translation adjustment, Before-Tax Amount (8,765) 20,247
Foreign currency translation adjustment, Net-of-Tax Amount (8,765) 20,247
Total Other Comprehensive (Loss) Income, Before-Tax Amount (8,861) 20,437
Total Other Comprehensive (Loss) Income, Tax (Expense) Benefit 30 (59)
Net current period other comprehensive (loss) income $ (8,831) $ 20,378
v3.26.1
Redeemable Non-controlling Interest - Summary of Redeemable Non-controlling Interest Activity (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Redeemable Noncontrolling Interest [Line Items]    
Balance at beginning of period $ 373,328 $ 422,943
Redemption of redeemable non-controlling interest (4,311) (49,615)
Net income attributable to redeemable non-controlling interests 2,251 9,413
Annual recurring compensation earned (2,251) (9,413)
Balance at end of period $ 369,017 $ 373,328
v3.26.1
Redeemable Non-controlling Interest - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Redeemable Noncontrolling Interest [Line Items]      
Accrued annual recurring compensation to redeemable non-controlling shareholders $ 2.2 $ 2.4  
DPLTA [Member]      
Redeemable Noncontrolling Interest [Line Items]      
Accrued annual recurring compensation to redeemable non-controlling shareholders $ 2.2   $ 9.3
Adtran Networks [Member]      
Redeemable Noncontrolling Interest [Line Items]      
Equity ownership percentage 28.80%   29.20%
v3.26.1
Loss Per Share - Summary of Calculation of Basic and Diluted Loss Per Share (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Numerator      
Net Loss attributable to ADTRAN Holdings, Inc. $ (1,321) $ (11,267)  
Effect of redemption of RNCI 301 (3)  
Net loss attributable to ADTRAN Holdings, Inc. common stockholders $ (1,020) $ (11,270)  
Denominator      
Weighted average number of shares – basic 80,321 79,534  
Effect of dilutive securities      
Weighted average number of shares – diluted 80,321 79,534 80,321
Loss per share attributable to ADTRAN Holdings, Inc. - basic $ (0.01) [1] $ (0.14) [1] $ (0.01)
Loss per share attributable to ADTRAN Holdings, Inc. - diluted $ (0.01) [1] $ (0.14) [1] $ (0.01)
[1] Loss per common share attributable to ADTRAN Holdings, Inc. - basic and diluted - reflects a $0.3 million and a $(3) thousand effect of redemption of RNCI for the three months ended March 31, 2026 and 2025. See Note 15 for additional information.
v3.26.1
Loss Per Share - Schedule of Antidilutive Securities Excluded from Earnings Per Share Computation (Details) - shares
shares in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Convertible Senior Notes [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive effect excluded calculation of diluted earnings per share 2,440  
Stock Options [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive effect excluded calculation of diluted earnings per share 794 711
PSUs, RSUs and Restricted Stock [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive effect excluded calculation of diluted earnings per share 446 202
v3.26.1
Segment Information - Additional Information (Detail)
$ in Millions
3 Months Ended
Mar. 31, 2026
USD ($)
Segment
Mar. 31, 2025
USD ($)
Segment Reporting Information [Line Items]    
Number of reportable segments | Segment 2  
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration] srt:ChiefExecutiveOfficerMember  
Depreciation expense $ 8.1 $ 6.9
Network Solutions [Member]    
Segment Reporting Information [Line Items]    
Depreciation expense 1.7 1.3
Services & Support [Member] | Maximum [Member]    
Segment Reporting Information [Line Items]    
Depreciation expense $ 0.1 $ 0.1
v3.26.1
Segment Information - Revenue and Gross Profit of Reportable Segments (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Revenue $ 286,086 $ 247,744
Cost of Revenue 173,098 152,568
Gross Profit 112,988 95,176
Network Solutions [Member]    
Segment Reporting Information [Line Items]    
Revenue 237,941 202,217
Cost of Revenue 154,648 134,241
Gross Profit 83,293 67,976
Services & Support [Member]    
Segment Reporting Information [Line Items]    
Revenue 48,145 45,527
Cost of Revenue 18,450 18,327
Gross Profit $ 29,695 $ 27,200
v3.26.1
Segment Information - Revenue Information by Geographic Area (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Revenue from External Customer [Line Items]    
Revenue $ 286,086 $ 247,744
United States [Member]    
Revenue from External Customer [Line Items]    
Revenue 146,167 103,189
United Kingdom [Member]    
Revenue from External Customer [Line Items]    
Revenue 43,805 62,909
Germany [Member]    
Revenue from External Customer [Line Items]    
Revenue 33,925 27,188
Other International [Member]    
Revenue from External Customer [Line Items]    
Revenue $ 62,189 $ 54,458
v3.26.1
Commitments and Contingencies - Additional Information (Detail)
€ in Thousands, shares in Thousands, $ in Thousands
1 Months Ended 3 Months Ended
Apr. 30, 2026
USD ($)
Apr. 30, 2026
EUR (€)
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2026
EUR (€)
shares
Mar. 31, 2025
USD ($)
shares
Mar. 31, 2025
EUR (€)
shares
Mar. 31, 2026
EUR (€)
Dec. 31, 2025
USD ($)
Commitments And Contingencies Line Items                
Percentage of guaranteed interest rate     5.00%       5.00%  
Percentage of guaranteed interest rate plus a variable component     1.27%       1.27%  
Aggregate exit compensation payments obligation including guaranteed interest     $ 351,700       € 304,400  
Expire date of exit compensation     Mar. 16, 2023 Mar. 16, 2023        
Annual recurring compensation obligation     $ 9,000 € 7,800 $ 9,000 € 7,800    
Accrued annual recurring compensation obligation     2,200   2,400      
Commitments related to performance bonds     $ 22,200         $ 22,400
Commitments related to performance bonds expiration month and year     2029-04 2029-04        
Purchase obligations     $ 223,700          
Number of shares tendered | shares     200 200        
Liability     $ 678,525         685,335
Employeess deferrals     $ 23,449         32,203
401(k) Retirement Plan                
Commitments And Contingencies Line Items                
Employeess deferrals               $ 1,400
Adtran Networks [Member]                
Commitments And Contingencies Line Items                
Exit compensation payments         $ 13 € 12    
Number of shares tendered | shares     200 200        
Adtran Networks [Member] | Maximum [Member]                
Commitments And Contingencies Line Items                
Number of shares tendered | shares     1 1 1 1    
Adtran Networks [Member] | Subsequent Events [Member]                
Commitments And Contingencies Line Items                
Exit compensation payments $ 4,100 € 3,600