Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2025
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 SE (“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. Liquidity, Domination and Profit and Loss Transfer Agreement and Credit Facility 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 applies to the net loss generated by Adtran Networks in 2024 and it will apply to any net loss generated by Adtran Networks in 2025. 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 2.27% as of March 31, 2025. 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 €338.5 million or approximately $366.1 million, based on an exchange rate as of March 31, 2025, and reflecting interest accrued through March 31, 2025 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). The Company expects to receive a ruling on a procedural matter in the DPLTA appraisal proceedings during the latter half of 2025 or 2026, which ruling, depending on outcome, will likely be appealed and may take 6-12 months to be decided on appeal. The Company does not expect that a trial on the merits of the DPLTA appraisal proceedings will commence until the procedural matter has been resolved. The proceeding for the trial on the merits of the DPLTA will likely take a minimum of 12 months for a ruling and such ruling may likewise 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 €8.9 million (or $9.7 million based on the current exchange rate) per year assuming none of the minority Adtran Networks shareholders as of March 31, 2025 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 2023 fiscal year, Adtran Networks’ ordinary general shareholders’ meeting occurred on June 28, 2024 and, therefore, the Annual Recurring Compensation was paid on July 3, 2024. With respect to the 2024 fiscal year, Adtran Networks’ ordinary general shareholder meeting is scheduled for June 27, 2025 and, therefore, the Annual Recurring Compensation will be due on July 2, 2025. During the three months ended March 31, 2025 and 2024, we accrued $2.4 million and $2.5 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 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. 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 four times. The Company had access to $180.7 million on its Credit Facility for future borrowings; however, as of March 31, 2025 and the date of this filing the Company was limited to additional borrowings of $25.8 million 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. See Note 10, Revolving Credit Agreements for additional information regarding the terms of the Wells Fargo Credit Agreement. As of March 31, 2025, and as of the date of issuance of these financial statements, the Company does not have sufficient liquidity to meet the substantial majority of its payment obligations under the DPLTA pertaining to Exit Compensation. For the three months ended March 31, 2025 and 2024, less than one thousand shares of Adtran Networks stock were tendered to the Company and Exit Compensation payments of approximately €12 thousand and €4 thousand, respectively, or approximately $13 thousand and $5 thousand based on the applicable exchange rates at the time of the transaction, were paid to Adtran Networks shareholders. On April 14, 2025, 0.4 million shares of Adtran Networks stock were tendered to the Company and Exit Compensation payments of approximately €7.0 million or approximately $7.5 million, based on the applicable exchange rate at the time of the transaction, will be 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 that the Company expects to receive a procedural decision during 2025 or 2026 that will likely be appealed and, while the date of a decision by the court on the merits of the case is uncertain, it will 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. The Company experienced revenue declines in the year ended December 31, 2024. However, customers have started to replenish their inventories to meet increasing demand and management expects orders and billings to increase during the remainder of 2025. The Company continues to implement plans to preserve cash liquidity to maintain compliance with the Company’s covenants in case of further impacts related to customer inventory reduction initiatives and uncertain macroeconomic conditions. Additionally, the Company suspended dividend payments and effectuated a business efficiency program (the "Business Efficiency Program"), which targeted the reduction of ongoing operating expenses and focused on enhancing capital efficiency. The Business Efficiency Program was completed as of December 31, 2024, other than the Company's aim of selling its headquarters. The Company has determined that it is probable that the sale of its headquarters in Huntsville will occur within the next twelve months after December 31, 2024. The Company may need to further reduce capital expenditures and/or take other steps to preserve working capital in order to ensure that it can meet its needs and obligations and maintain compliance with its debt covenants. In summary, the Company believes that its cash and cash equivalents, investments, working capital management initiatives and availability to access cash under the Wells Fargo credit facility will be adequate to meet our business operating requirements, our capital expenditures and our expected obligations under the DPLTA, including anticipated levels of Exit Compensation and to support our ability to continue to comply with our debt covenants under the Credit Facility and continue as a going concern, for at least the next twelve months, from the issuance of these financial statements. See Note 10, Revolving Credit Agreements, for additional information regarding the terms 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, 2024, 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. Amendment No. 1 to the Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on May 20, 2025 (the "2024 Form 10-K/A"). Restatement of Previously Issued Financial Statements As discussed in the financial statements as of and for the year ended December 31, 2024 included in our amended 2024 Annual Report on Form 10-K/A, we identified errors in our previously issued financial statements. In addition, on May 13, 2025, the Company announced that it needed additional time to complete its quarterly reporting process as a result of the restatements to the annual periods ended December 31, 2023 and 2024 and for the interim periods ended March 31, 2024, June 30, 2024 and September 30, 2024, as well as to complete its evaluation of internal control over financial reporting as of December 31, 2024 as a result of errors related to the historical accounting for certain inventory and cost of goods sold transactions in its Adtran Networks SE subsidiary (the “Adjustment”). As a result, the Company filed a Form 12b-25 with the SEC and delayed the filing of this report. In connection with the identification of the Adjustment, the Audit Committee has overseen 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, which is substantially complete, it has been 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 was not communicated to the Audit Committee or the independent auditors prior to the filing of the initial 2024 Annual Report on Form 10-K. As described in Part I, Item 4 of this report, the Company is taking certain remedial actions to address the material weaknesses in its internal controls associated with these findings. The identified errors impacted the Condensed Consolidated Financial Statements as of and for the three months ended March 31, 2024, among other periods as previously disclosed. Below is a summary description of the significant errors in the Company's Condensed Consolidated Financial Statements as of and for the quarter ended March 31, 2024: ADJ 1 - Pursuant to the terms of the DPLTA, each Adtran Networks shareholder (other than the Company) is entitled to receive from us an Annual Recurring Compensation payment of €0.52 per share. The Company erroneously accrued this liability every quarter at €0.59 per share, overstating the associated accrual, the net income attributable to non-controlling interest and the net loss attributable to ADTRAN Holdings, Inc. for fiscal periods beginning with the quarter ended March 31, 2023 through the quarter ended June 30, 2024. ADJ 2 - For the periods beginning with the quarter ended March 31, 2023 through the quarter ended June 30, 2024 the Company remeasured the redeemable non-controlling interest each quarter-end at the current exchange rate of euros to U.S. Dollar. The Company treated the redeemable non-controlling interest as a monetary mezzanine equity instrument but should have treated it as a non-monetary mezzanine equity instrument not subject to remeasurement. ADJ 3 - For the year ended December 31, 2023 through the year ended December 31, 2024, the Company understated cost of revenue and overstated inventory in the Company's Adtran Networks subsidiary due to a system error. In addition, there were adjustments in the Company's U.S and Australian subsidiaries related to inventory reserves that were understated. ADJ 4 - For the year ended December 31, 2023 through the year ended December 31, 2024, the Company understated goodwill and overstated income tax receivable. The understatement was attributable to corrections to goodwill and deferred income tax associated with goodwill for an internal divestiture of a wholly owned subsidiary required by statutory laws in Europe. In addition to the misstatements identified above, the Company has corrected other immaterial errors. These other errors are quantitatively and qualitatively immaterial, individually and in the aggregate. However, the Company has corrected these other errors as part of the correction for the significant errors described above. We assessed the materiality of the errors on prior period consolidated financial statements in accordance with SEC Staff Accounting Bulletin No. 99, “Materiality,” codified in ASC Topic 250, Accounting Changes and Error Corrections. Based on this assessment, we concluded that the errors, in the aggregate, are material to the March 31, 2024 financial statements and therefore, we are restating those financial statements herein. Furthermore, we made adjustments to correct for other previously identified immaterial errors. The Company has also restated impacted amounts within the accompanying footnotes to the Condensed Consolidated Financial Statements. See Note 18 for further information about the restatement. 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, warranty reserves, customer rebates, 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, currency fluctuations and political tensions as of March 31, 2025, 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. Recent Accounting Pronouncements Not Yet Adopted In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2024-03, "Disaggregation of Income Statement Expenses (DISE) (Topic 220): Improvements to Income Statement Disclosures", 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 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. In December 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2023-09, "Income Taxes (Topic 740): Improvements to Income Tax Disclosures", which is intended to enhance the transparency, decision usefulness and effectiveness of income tax disclosures. The amendments in this ASU require a public entity to disclose a tabular tax rate reconciliation, using both percentages and currency, with specific categories. A public entity is also required to provide a qualitative description of the states and local jurisdictions that make up the majority of the effect of the state and local income tax category and the net amount of income taxes paid, disaggregated by federal, state and foreign taxes and also disaggregated by individual jurisdictions. The amendments also remove certain disclosures that are no longer considered cost beneficial. The amendments are effective prospectively for annual periods beginning after December 15, 2024, and early adoption and retrospective application are permitted. The Company is currently evaluating the effect that adoption of ASU 2023-09 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. Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified for consistency with current year presentation. These reclassifications had no effect on reported results of operations. An adjustment has been made to the Consolidated Statement of Cash Flows for the quarter ended March 31, 2024, to reclassify between Property, Plant and Equipment and Intangible Assets.

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 SE (“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.

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

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 applies to the net loss generated by Adtran Networks in 2024 and it will apply to any net loss generated by Adtran Networks in 2025.

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 2.27% as of March 31, 2025. 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 €338.5 million or approximately $366.1 million, based on an exchange rate as of March 31, 2025, and reflecting interest accrued through March 31, 2025 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). The Company expects to receive a ruling on a procedural matter in the DPLTA appraisal proceedings during the latter half of 2025 or 2026, which ruling, depending on outcome, will likely be appealed and may take 6-12 months to be decided on appeal. The Company does not expect that a trial on the merits of the DPLTA appraisal proceedings will commence until the procedural matter has been resolved. The proceeding for the trial on the merits of the DPLTA will likely take a minimum of 12 months for a ruling and such ruling may likewise 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 €8.9 million (or $9.7 million based on the current exchange rate) per year assuming none of the minority Adtran Networks shareholders as of March 31, 2025 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 2023 fiscal year, Adtran Networks’ ordinary general shareholders’ meeting occurred on June 28, 2024 and, therefore, the Annual Recurring Compensation was paid on July 3, 2024. With respect to the 2024 fiscal year, Adtran Networks’ ordinary general shareholder meeting is scheduled for June 27, 2025 and, therefore, the Annual Recurring Compensation will be due on July 2, 2025. During the three months ended March 31, 2025 and 2024, we accrued $2.4 million and $2.5 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 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.

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 four times. The Company had access to $180.7 million on its Credit Facility for future borrowings; however, as of March 31, 2025 and the date of this filing the Company was limited to additional borrowings of $25.8 million 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. See Note 10, Revolving Credit Agreements for additional information regarding the terms of the Wells Fargo Credit Agreement.

As of March 31, 2025, and as of the date of issuance of these financial statements, the Company does not have sufficient liquidity to meet the substantial majority of its payment obligations under the DPLTA pertaining to Exit Compensation. For the three months ended March 31, 2025 and 2024, less than one thousand shares of Adtran Networks stock were tendered to the Company and Exit Compensation payments of approximately €12 thousand and €4 thousand, respectively, or approximately $13 thousand and $5 thousand based on the applicable exchange rates at the time of the transaction, were paid to Adtran Networks shareholders. On April 14, 2025, 0.4 million shares of Adtran Networks stock were tendered to the Company and Exit Compensation payments of approximately €7.0 million or approximately $7.5 million, based on the applicable exchange rate at the time of the transaction, will be 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 that the Company expects to receive a procedural decision during 2025 or 2026 that will likely be appealed and, while the date of a decision by the court on the merits of the case is uncertain, it will 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.

The Company experienced revenue declines in the year ended December 31, 2024. However, customers have started to replenish their inventories to meet increasing demand and management expects orders and billings to increase during the remainder of 2025. The Company continues to implement plans to preserve cash liquidity to maintain compliance with the Company’s covenants in case of further impacts related to customer inventory reduction initiatives and uncertain macroeconomic conditions. Additionally, the Company suspended dividend payments and effectuated a business efficiency program (the "Business Efficiency Program"), which targeted the reduction of ongoing operating expenses and focused on enhancing capital efficiency. The Business Efficiency Program was completed as of December 31, 2024, other than the Company's aim of selling its headquarters. The Company has determined that it is probable that the sale of its headquarters in Huntsville will occur within the next twelve months after December 31, 2024. The Company may need to further reduce capital expenditures and/or take other steps to preserve working capital in order to ensure that it can meet its needs and obligations and maintain compliance with its debt covenants.

In summary, the Company believes that its cash and cash equivalents, investments, working capital management initiatives and availability to access cash under the Wells Fargo credit facility will be adequate to meet our business operating requirements, our capital expenditures and our expected obligations under the DPLTA, including anticipated levels of Exit Compensation and to support our ability to continue to comply with our debt covenants under the Credit Facility and continue as a going concern, for at least the next twelve months, from the issuance of these financial statements. See Note 10, Revolving Credit Agreements, for additional information regarding the terms of the Wells Fargo Credit agreement.

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, 2024, 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. Amendment No. 1 to the Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on May 20, 2025 (the "2024 Form 10-K/A").

Restatement of Previously Issued Financial Statements

As discussed in the financial statements as of and for the year ended December 31, 2024 included in our amended 2024 Annual Report on Form 10-K/A, we identified errors in our previously issued financial statements. In addition, on May 13, 2025, the Company announced that it needed additional time to complete its quarterly reporting process as a result of the restatements to the annual periods ended December 31, 2023 and 2024 and for the interim periods ended March 31, 2024, June 30, 2024 and September 30, 2024, as well as to complete its evaluation of internal control over financial reporting as of December 31, 2024 as a result of errors related to the historical accounting for certain inventory and cost of goods sold transactions in its Adtran Networks SE subsidiary (the “Adjustment”). As a result, the Company filed a Form 12b-25 with the SEC and delayed the filing of this report.

In connection with the identification of the Adjustment, the Audit Committee has overseen 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, which is substantially complete, it has been 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 was not communicated to the Audit Committee or the independent auditors prior to the filing of the initial 2024 Annual Report on Form 10-K. As described in Part I, Item 4 of this report, the Company is taking certain remedial actions to address the material weaknesses in its internal controls associated with these findings.

The identified errors impacted the Condensed Consolidated Financial Statements as of and for the three months ended March 31, 2024, among other periods as previously disclosed. Below is a summary description of the significant errors in the Company's Condensed Consolidated Financial Statements as of and for the quarter ended March 31, 2024:

ADJ 1 - Pursuant to the terms of the DPLTA, each Adtran Networks shareholder (other than the Company) is entitled to receive from us an Annual Recurring Compensation payment of €0.52 per share. The Company erroneously accrued this liability every quarter at €0.59 per share, overstating the associated accrual, the net income attributable to non-controlling interest and the net loss attributable to ADTRAN Holdings, Inc. for fiscal periods beginning with the quarter ended March 31, 2023 through the quarter ended June 30, 2024.

ADJ 2 - For the periods beginning with the quarter ended March 31, 2023 through the quarter ended June 30, 2024 the Company remeasured the redeemable non-controlling interest each quarter-end at the current exchange rate of euros to U.S. Dollar. The Company treated the redeemable non-controlling interest as a monetary mezzanine equity instrument but should have treated it as a non-monetary mezzanine equity instrument not subject to remeasurement.

ADJ 3 - For the year ended December 31, 2023 through the year ended December 31, 2024, the Company understated cost of revenue and overstated inventory in the Company's Adtran Networks subsidiary due to a system error. In addition, there were adjustments in the Company's U.S and Australian subsidiaries related to inventory reserves that were understated.

ADJ 4 - For the year ended December 31, 2023 through the year ended December 31, 2024, the Company understated goodwill and overstated income tax receivable. The understatement was attributable to corrections to goodwill and deferred income tax associated with goodwill for an internal divestiture of a wholly owned subsidiary required by statutory laws in Europe.

In addition to the misstatements identified above, the Company has corrected other immaterial errors. These other errors are quantitatively and qualitatively immaterial, individually and in the aggregate. However, the Company has corrected these other errors as part of the correction for the significant errors described above.

We assessed the materiality of the errors on prior period consolidated financial statements in accordance with SEC Staff Accounting Bulletin No. 99, “Materiality,” codified in ASC Topic 250, Accounting Changes and Error Corrections. Based on this assessment, we concluded that the errors, in the aggregate, are material to the March 31, 2024 financial statements and therefore, we are restating those financial statements herein. Furthermore, we made adjustments to correct for other previously identified immaterial errors. The

Company has also restated impacted amounts within the accompanying footnotes to the Condensed Consolidated Financial Statements. See Note 18 for further information about the restatement.

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, warranty reserves, customer rebates, 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, currency fluctuations and political tensions as of March 31, 2025, 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.

Recent Accounting Pronouncements Not Yet Adopted

In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2024-03, "Disaggregation of Income Statement Expenses (DISE) (Topic 220): Improvements to Income Statement Disclosures", 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 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.

In December 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2023-09, "Income Taxes (Topic 740): Improvements to Income Tax Disclosures", which is intended to enhance the transparency, decision usefulness and effectiveness of income tax disclosures. The amendments in this ASU require a public entity to disclose a tabular tax rate reconciliation, using both percentages and currency, with specific categories. A public entity is also required to provide a qualitative description of the states and local jurisdictions that make up the majority of the effect of the state and local income tax category and the net amount of income taxes paid, disaggregated by federal, state and foreign taxes and also disaggregated by individual jurisdictions. The amendments also remove certain disclosures that are no longer considered cost beneficial. The amendments are effective prospectively for annual periods beginning after December 15, 2024, and early adoption and retrospective application are permitted. The Company is currently evaluating the effect that adoption of ASU 2023-09 will have on our disclosures.