Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2024

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 our 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 SE ("Adtran Networks"), as the controlled company, as 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 generally 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 for the first time to the net loss generated in 2023.

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 3.37% as of December 31, 2024. 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 €333.2 million or approximately $344.9 million, based on an exchange rate as of December 31, 2024 and reflecting interest accrued through December 31, 2024 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 will 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 €8.9 million (or $9.3 million based on the current exchange rate) per year assuming none of the minority Adtran Networks shareholders as of December 31, 2024 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 year ended December 31, 2024 and 2023, we accrued $9.8 million and $10.1 million, respectively, in Annual Recurring Compensation. The Annual Recurring Compensation is reflected as an increase to retained deficit in the 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. For the year ended December 31, 2024, approximately 831 thousand shares of Adtran Networks stock were tendered to the Company. This resulted in total Exit Compensation payments of approximately €15.7 million, or approximately $17.4 million, based on exchange rates at the time of the transactions, being paid to Adtran Networks shareholders. For the year ended December 31, 2023, a total of 67 thousand shares of Adtran Networks stock was tendered to the Company and Exit Compensation payments of approximately €1.2 million or approximately $1.3 million based on an exchange rate as of December 31, 2023, were paid to Adtran Networks shareholders.

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 $180.8 million on its Credit Facility for future borrowings; however, as of December 31 2024, the Company was limited to additional borrowings of $36.1 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 11, Credit Agreements for additional information regarding the terms of the Wells Fargo Credit Agreement and its amendments.

As of December 31, 2024, and as of the date of issuance of these financial statements, the Company does not have sufficient liquidity to meet payment obligations under the DPLTA pertaining to Exit Compensation. While the Company did experience $17.4 million of redemptions during 2024, 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 2024. The Company is implementing 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 was substantially 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 our headquarters in Huntsville will occur within the next twelve months after December 31, 2024. We may need to further reduce capital expenditure and/or take other steps to preserve working capital in order to ensure that we can meet our needs and obligations and maintain compliance with our 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, for at least the next twelve months, from the issuance of

these financial statements. See Note 11, Credit Agreements, for additional information regarding the terms of the Amendments of the Wells Fargo Credit agreement.

Note 1 - Summary Of Significant Accounting Policies

Basis of Presentation

The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”) and include the financial position, results of operations, comprehensive (loss) income, changes in equity and cash flows of Adtran and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Restatement of Previously Issued Consolidated Financial Statements

On May 13, 2025, the Audit Committee of the Board of Directors (the “Audit Committee”) of the Company concluded, after considering the recommendations of management, that the Company’s (i) audited consolidated financial statements as of and for the years ended December 31, 2024 (“Fiscal 2024”) and December 31, 2023 (“Fiscal 2023”) included in the Company’s Annual Report on Form 10-K filed with the SEC on March 3, 2025 (the “2024 Form 10-K”), and (ii) unaudited condensed consolidated financial statements as of and for the interim periods ended March 31, 2024, June 30, 2024 and September 30, 2024 (the “2024 Interim Periods”) included in the Company’s Quarterly Reports filed with the SEC on May 10, 2024, August 9, 2024, and November 12, 2024, respectively (such 2024 Interim Periods, collectively with Fiscal 2024 and Fiscal 2023, the “Non-Reliance Periods”), as well as the relevant portions of any communication which describe or are based on such financial statements, should no longer be relied upon.

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 its filing of its Quarterly Report on Form 10-Q for the quarter ended March 31, 2025.

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 were not communicated to the Audit Committee or the independent auditors prior to the filing of the initial 2024 and 2023 Annual Reports on Form 10-K. As described in Item 9A of this Amendment No. 1, the Company is taking certain remedial actions to address the material weaknesses in its internal controls associated with these findings.

The impact of the correction of the misstatements and errors on the Condensed Consolidated Financial Statements for the quarterly periods ended March 31, 2024, June 30, 2024 and September 30, 2024 are summarized in Note 22, Restatement of Quarterly Financial Information (Unaudited).

The impact of the correction of the misstatements and errors has been reflected within Schedule II – Valuation and Qualifying Accounts for the year ended December 31, 2024.

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 Fiscal 2024 and Fiscal 2023 and therefore, we are restating those financial statements herein. Furthermore, we made adjustments to correct for other previously identified immaterial errors. The impact of the correction of the misstatements and errors on the Consolidated Financial Statements for the years ended December 31, 2024 and 2023, as well as previously identified immaterial errors which have now been corrected, is summarized below. The Company has also restated impacted amounts within the accompanying footnotes to the Consolidated Financial Statements.

The impact of the correction of the misstatements and errors on the Consolidated Statements of Cash Flows were driven by changes in the related Consolidated Balance Sheet and Consolidated Statement of Loss and Comprehensive Income (Loss) line items. Below is a summary description of the significant errors:

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.

The following tables reflect the impact of the restatements to the specific line items presented in the Company’s previously reported Consolidated Balance Sheets as of December 31, 2024 and 2023.

		As of December 31, 2024
ASSETS	Adj Reference	As Reported			Adjustment			As Restated
Current Assets
Cash and cash equivalents		$	77,567		$	(1,546	)	$	76,021
Accounts receivable, less allowance for credit losses of $1,300 as of December 31, 2024			178,030			—			178,030
Other receivables			9,775			—			9,775
Income tax receivable			5,461			—			5,461
Inventory, net	ADJ 3		269,337			(7,780	)		261,557
Assets held for sale			11,901			—			11,901
Prepaid expenses and other current assets			58,534			(2,139	)		56,395
Total Current Assets			610,605			(11,465	)		599,140
Property, plant and equipment, net			102,942			3,512			106,454
Deferred tax assets, net			17,826			—			17,826
Goodwill			52,918			—			52,918
Intangibles, net			284,893			—			284,893
Other non-current assets			78,128			—			78,128
Long-term investments			32,060			—			32,060
Total Assets		$	1,179,372		$	(7,953	)	$	1,171,419
LIABILITIES AND EQUITY
Current Liabilities
Accounts payable		$	170,451		$	1,374		$	171,825
Unearned revenue			52,701			—			52,701
Accrued expenses and other liabilities			35,704			(1,546	)		34,158
Accrued wages and benefits			32,853			—			32,853
Income tax payable			1,936			—			1,936
Total Current Liabilities			293,645			(172	)		293,473
Non-current revolving credit agreement outstanding			189,576			-			189,576
Deferred tax liabilities			30,690			(318	)		30,372
Non-current unearned revenue			22,065			—			22,065
Non-current pension liability			8,983			—			8,983
Deferred compensation liability			33,203			—			33,203
Non-current lease obligations			25,925			—			25,925
Other non-current liabilities			17,928			—			17,928
Total Liabilities			622,015			(490	)		621,525
Commitments and contingencies (see Note 18)
Redeemable Non-Controlling Interest			422,943			—			422,943
Equity
Common stock, par value $0.01 per share; 200,000 shares authorized;    79,483 shares issued and 79,218 outstanding as of December 31, 2024			795			—			795
Additional paid-in capital			808,913			—			808,913
Accumulated other comprehensive income	ADJ 3, 4		10,897			357			11,254
Retained deficit	ADJ 3, 4		(680,993	)		(7,820	)		(688,813	)
Less treasury stock at cost: 266 shares as of December 31, 2024			(5,198	)		—			(5,198	)
Total Equity			134,414			(7,463	)		126,951
Total Liabilities and Equity		$	1,179,372		$	(7,953	)	$	1,171,419

		As of December 31, 2023
ASSETS	Adj Reference	As Reported			Adjustment			As Restated
Current Assets
Cash and cash equivalents		$	87,167		$	—		$	87,167
Accounts receivable, less allowance for credit losses of $400 as of December 31, 2023			216,445			(6,708	)		209,737
Other receivables			17,450			—			17,450
Income tax receivable			7,933			(4,735	)		3,198
Inventory, net	ADJ 3		362,295			(1,871	)		360,424
Prepaid expenses and other current assets			45,566			(4,575	)		40,991
Total Current Assets			736,856			(17,889	)		718,967
Property, plant and equipment, net			113,582			4,575			118,157
Deferred tax assets, net	ADJ 4		25,787			3,507			29,294
Goodwill	ADJ 4		353,415			4,735			358,150
Intangibles, net			337,423			—			337,423
Other non-current assets			87,706			—			87,706
Long-term investments			27,743			—			27,743
Total Assets		$	1,682,512		$	(5,072	)	$	1,677,440
LIABILITIES AND EQUITY
Current Liabilities
Accounts payable		$	162,922		$	—		$	162,922
Unearned revenue			46,731			(4,231	)		42,500
Accrued expenses and other liabilities	ADJ 1		37,607			(1,403	)		36,204
Accrued wages and benefits			27,030			122			27,152
Income tax payable	ADJ 4		5,221			—			5,221
Total Current Liabilities			279,511			(5,512	)		273,999
Non-current revolving credit agreement outstanding			195,000			—			195,000
Deferred tax liabilities	ADJ 4		35,655			(89	)		35,566
Non-current unearned revenue			25,109			(2,477	)		22,632
Non-current pension liability			12,543			—			12,543
Deferred compensation liability			29,039			—			29,039
Non-current lease obligations			31,420			—			31,420
Other non-current liabilities			28,657			—			28,657
Total Liabilities			636,934			(8,078	)		628,856
Commitments and contingencies (see Note 20)
Redeemable Non-Controlling Interest	ADJ 2		451,756			(8,429	)		443,327
Equity
Common stock, par value $0.01 per share; 200,000 shares authorized;    78,970 shares issued and 78,674 outstanding as of December 31, 2023			790			—			790
Additional paid-in capital			795,304			(836	)		794,468
Accumulated other comprehensive income	ADJ 1		47,461			69			47,530
Retained deficit	ADJ 1, 2, 4		(243,908	)		12,202			(231,706	)
Less treasury stock at cost: 297 shares as of December 31, 2023			(5,825	)		—			(5,825	)
Total Equity			593,822			11,435			605,257
Total Liabilities and Equity		$	1,682,512		$	(5,072	)	$	1,677,440

The following tables reflect the impact of the restatements to the specific line items presented in the Company’s previously reported Consolidated Statement of Loss and the Consolidated Statement of Comprehensive Loss for the years ended December 31, 2024 and 2023.

		Year Ended December 31, 2024
	Adj Reference	As Reported			Adjustment			As Restated
Revenue
Network Solutions		$	738,964		$	—		$	738,964
Services & Support			183,756			—			183,756
Total Revenue			922,720			—			922,720
Cost of Revenue
Network Solutions	ADJ 3		511,070			6,150			517,220
Network Solutions - inventory write-down and other charges			8,597			—			8,597
Services & Support			72,739			—			72,739
Total Cost of Revenue			592,406			6,150			598,556
Gross Profit			330,314			(6,150	)		324,164
Selling, general and administrative expenses			233,369			(451	)		232,918
Research and development expenses			221,463			(5	)		221,458
Goodwill impairment	ADJ 4		292,583			4,770			297,353
Operating Loss			(417,101	)		(10,464	)		(427,565	)
Interest and dividend income			3,058			—			3,058
Interest expense			(22,053	)		—			(22,053	)
Net investment gain			3,587			—			3,587
Other income, net			246			—			246
Loss Before Income Taxes			(432,263	)		(10,464	)		(442,727	)
Income tax expense	ADJ 4		(8,785	)		1,445			(7,340	)
Net Loss		$	(441,048	)	$	(9,019	)	$	(450,067	)
Less: Net Income attributable to non-controlling interest(1)			9,824			—			9,824
Net Loss attributable to ADTRAN Holdings, Inc.		$	(450,872	)	$	(9,019	)	$	(459,891	)
Weighted average shares outstanding – basic			78,928			78,928			78,928
Weighted average shares outstanding – diluted			78,928			78,928			78,928
Loss per common share attributable to ADTRAN Holdings, Inc. – basic		$	(5.67	)	$	(0.12	)	$	(5.79	)
Loss per common share attributable to ADTRAN Holdings, Inc. – diluted		$	(5.67	)	$	(0.12	)	$	(5.79	)
Net Loss		$	(441,048	)	$	(9,019	)	$	(450,067	)
Other Comprehensive Loss, net of tax
Defined benefit plan adjustments			1,479			—			1,479
Foreign currency translation loss	ADJ 3, 4		(38,047	)		292			(37,755	)
Other Comprehensive Loss, net of tax			(36,568	)		292			(36,276	)
Comprehensive Loss, net of tax			(477,616	)		(8,727	)		(486,343	)
Less: Comprehensive Income attributable to non-controlling interest, net of tax			9,824			—			9,824
Comprehensive Loss attributable to ADTRAN Holdings, Inc., net of tax		$	(487,440	)	$	(8,727	)	$	(496,167	)

(1) For the year ended December 31, 2024 we accrued $9.8 million of net income attributable to non-controlling interest, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA

		Year Ended December 31, 2023
	Adj Reference	As Reported			Adjustment			As Restated
Revenue
Network Solutions		$	974,389		$	—		$	974,389
Services & Support			174,711			—			174,711
Total Revenue			1,149,100			—			1,149,100
Cost of Revenue
Network Solutions	ADJ 3		722,582			1,936			724,518
Network Solutions - Inventory Write Down			24,313			—			24,313
Services & Support			69,142			—			69,142
Total Cost of Revenue			816,037			1,936			817,973
Gross Profit			333,063			(1,936	)		331,127
Selling, general and administrative expenses			258,149			461			258,610
Research and development expenses			258,311			—			258,311
Goodwill impairment			37,874			—			37,874
Operating Loss			(221,271	)		(2,397	)		(223,668	)
Interest and dividend income			2,340			—			2,340
Interest expense			(16,299	)		—			(16,299	)
Net investment gain			2,754			—			2,754
Other income (expense), net			1,266			—			1,266
Loss Before Income Taxes			(231,210	)		(2,397	)		(233,607	)
Income tax expense	ADJ 4		(28,133	)		(166	)		(28,299	)
Net Loss		$	(259,343	)	$	(2,563	)	$	(261,906	)
Net Income attributable to non-controlling interest (1)	ADJ 1		8,345			(1,399	)		6,946
Net Loss attributable to ADTRAN Holdings, Inc.		$	(267,688	)	$	(1,164	)	$	(268,852	)
Weighted average shares outstanding – basic			78,416			78,416			78,416
Weighted average shares outstanding – diluted			78,416			78,416			78,416
Loss per common share attributable to ADTRAN Holdings, Inc. – basic		$	(3.41	)	$	(0.01	)	$	(3.43	)
Loss per common share attributable to ADTRAN Holdings, Inc. – diluted		$	(3.41	)	$	(0.01	)	$	(3.43	)
Net Loss		$	(259,343	)	$	(2,563	)	$	(261,906	)
Other Comprehensive Loss, net of tax
Net unrealized gain (loss) on available-for-sale securities			454			—			454
Defined benefit plan adjustments			(1,490	)		—			(1,490	)
Foreign currency translation gain	ADJ 1		22,753			69			22,822
Other Comprehensive Loss, net of tax			21,717			69			21,786
Comprehensive (Loss), net of tax			(237,626	)		(2,494	)		(240,120	)
Less: Comprehensive Income attributable to non-controlling interest	ADJ 1		8,727			(1,399	)		7,328
Comprehensive (Loss) attributable to ADTRAN Holdings, Inc., net of tax		$	(246,353	)	$	(1,095	)	$	(247,448	)

(1) For the year ended December 31, 2023, we have recognized $10.1 million, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA partially offset by a $3.2 million net loss attributable to non-controlling interests pre-DPLTA for the year ended December 31, 2023.

The following tables reflect the impact of the restatement to the specific line items presented in the Company's previously reported Consolidated Statement of Changes in Stockholders Equity for the periods ended December 31, 2024 and 2023:

	Retained Deficit									Accumulated Other Comprehensive Income								Additional paid-in capital
(In thousands)	As Reported			Adjustment			As Restated			As Reported			Adjustment		As Restated			As Reported			Adjustment			As Restated
Balance as of December 31, 2023	$	(243,908	)	$	12,202		$	(231,706	)	$	47,461		$	69	$	47,530		$	795,304		$	(836	)	$	794,468
Net loss		(441,048	)		(9,019	)		(450,067	)		—			—		—			—			—			—
Annual recurring compensation earned		(9,824	)		—			(9,824	)		—			—		—			—			—			—
Remeasurement of redeemable non-controlling interest		—			—			—			—			—		—			(1,175	)		—			(1,175	)
Other comprehensive loss, net of tax		—			—			—			(36,568	)		292		(36,276	)		—			—			—
Deferred compensation adjustments, net of tax		—			—			—			—			—		—			(368	)		—			(368	)
ADTRAN RSUs and restricted stock vested		(1,026	)		—			(1,026	)		—			—		—			—			—			—
ADTRAN stock options exercised		824			—			824			—			—		—			—			—			—
Modification of Stock Options		—			—			—			—			—		—			(190	)		—			(190	)
Redemption of redeemable non-controlling interest		2,986			—			2,986			—			—		—			—			—			—
ADTRAN stock-based compensation expense		—			—			—			—			—		—			14,825			—			14,825
Adtran Networks stock-based compensation expense		—			—			—			—			—		—			517			836			1,353
Balance as of December 31, 2024	$	(691,996	)	$	3,183		$	(688,813	)	$	10,893		$	361	$	11,254		$	808,913		$	-		$	808,913

	Retained Deficit									Accumulated Other Comprehensive Income						Additional paid-in capital
(In thousands)	As Reported			Adjustment			As Restated			As Reported		Adjustment		As Restated		As Reported			Adjustment			As Restated
Balance as of December 31, 2022	$	55,338		$	—		$	55,338		$	26,126	$	—	$	26,126	$	895,834		$	—		$	895,834
Net loss		(256,164	)		(2,563	)		(258,727	)		—		—		—		—			—			—
Annual recurring compensation earned		(11,524	)		1,399			(10,125	)		—		—		—		—			—
Acquisition of Adtran Networks		—			3,762			3,762			—		—		—		—			—
Reclassification and remeasurement from equity to mezzanine equity for non-controlling interests in Adtran Networks		—			—			—			—		—		—		(116,895	)		—			(116,895	)
Mezzanine equity for non-controlling interest in Adtran Networks for Adtran Networks stock options exercised		—			—			—			—		—		—		—			(1,175	)		(1,175	)
Other comprehensive income, net of tax		—			—			—			21,335		69		21,404		—			—
Dividend payments ($0.09 per share)		(21,237	)		—			(21,237	)		—		—		—		—			—			—
Dividends accrued on unvested restricted stock units		8			—			8			—		—		—		—			—			—
Deferred compensation adjustments, net of tax		(145	)		—			(145	)		—		—		—		—			—			—
ADTRAN RSUs and restricted stock vested		(1,115	)		—			(1,115	)		—		—		—		—			—			—
ADTRAN stock options exercised		164			—			164			—		—		—		—			—			—
Redemption of redeemable non-controlling interest		371			—			371			—		—		—		—			—			—
Foreign currency remeasurement of redeemable non-controlling interest		(9,604	)		9,604			—			—		—		—		—			—
Adtran Networks stock options exercised		—			—			—			—		—		—		323			—			323
Modification of stock options		—			—			—			—		—		—		—			339			339
ADTRAN stock-based compensation expense		—			—			—			—		—		—		16,016			—			16,016
Adtran Networks stock-based compensation expense		—			—			—			—		—		—		26			—			26
Balance as of December 31, 2023	$	(243,908	)	$	12,202		$	(231,706	)	$	47,461	$	69	$	47,530	$	795,304		$	(836	)	$	794,468

The following tables reflect the impact of the restatement to the specific line items presented in the Company's previously reported Consolidated Statements of Cash Flows for the years ended December 31, 2024 and 2023:

		Year Ended December 31, 2024
	Adj Reference	As Reported			Adjustment			As Restated
Cash flows from operating activities:
Net Loss		$	(441,048	)	$	(9,019	)	$	(450,067	)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization			90,985			(456	)		90,529
Goodwill impairment	ADJ 4		292,583			4,770			297,353
Amortization of debt issuance cost			3,950			—			3,950
Gain on investments			(5,030	)		—			(5,030	)
Net loss on disposal of property, plant and equipment			1,371			—			1,371
Stock-based compensation expense			15,342			646			15,988
Deferred income taxes			2,247			3,329			5,576
Inventory write down - business efficiency program			4,135			—			4,135
Inventory reserves	ADJ 3		3,980			1,336			5,316
Change in operating assets and liabilities:
Accounts receivable, net			46,108			—			46,108
Other receivables			10,713			—			10,713
Income taxes receivable	ADJ 4		648			—			648
Inventory	ADJ 3		75,171			4,814			79,985
Prepaid expenses, other current assets and other assets			(10,718	)		(2,727	)		(13,445	)
Accounts payable			11,784			(1,546	)		10,238
Accrued expenses and other liabilities			5,519			(646	)		4,873
Income taxes payable			(4,670	)		—			(4,670	)
Net cash provided by operating activities			103,070			501			103,571
Cash flows from investing activities:
Purchases of property, plant and equipment			(32,454	)		(2,047	)		(34,501	)
Purchases of intangibles - developed technology			(30,671	)		—			(30,671	)
Proceeds from sales and maturities of available-for-sale investments			1,240			—			1,240
Purchases of available-for-sale investments			(268	)		—			(268	)
Payments for beneficial interests in securitized accounts receivable			(55	)		—			(55	)
Net cash used in investing activities			(62,208	)		(2,047	)		(64,255	)
Cash flows from financing activities:
Tax withholdings related to stock-based compensation settlements			(1,143	)		—			(1,143	)
Proceeds from stock option exercises			824			—			824
Proceeds from receivables purchase agreement			68,556			—			68,556
Repayments on receivables purchase agreement			(83,772	)		—			(83,772	)
Proceeds from draw on revolving credit agreements			26,000			—			26,000
Repayment of revolving credit agreements			(31,000	)		—			(31,000	)
Redemption of redeemable non-controlling interest			(17,398	)		—			(17,398	)
Payment of annual recurring compensation to non-controlling interest			(10,084	)		—			(10,084	)
Payment of debt issuance cost			(1,994	)		—			(1,994	)
Net cash used in financing activities			(50,011	)		—			(50,011	)
Net decrease in cash and cash equivalents			(9,149	)		(1,546	)		(10,695	)
Effect of exchange rate changes			(451	)		—			(451	)
Cash and cash equivalents, beginning of period			87,167			—			87,167
Cash and cash equivalents, end of period		$	77,567		$	(1,546	)	$	76,021
Supplemental disclosure of cash flow information:
Cash paid for interest		$	20,884		$	—		$	20,884
Cash paid for income taxes, net of refunds		$	6,691		$	—		$	6,691
Cash used in operating activities related to operating leases		$	9,274		$	—		$	9,274
Supplemental disclosure of non-cash investing activities:
Right-of-use assets obtained in exchange for lease obligations		$	5,317		$	—		$	5,317
Purchases of property, plant and equipment included in accounts payable		$	2,635		$	—		$	2,635
Redemption of redeemable non-controlling interest		$	2,986		$	—		$	2,986

		Year Ended December 31, 2023
	Adj Reference	As Reported			Adjustment			As Restated
Cash flows from operating activities:
Net Loss		$	(259,343	)	$	(2,563	)	$	(261,906	)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization			112,949			—			112,949
Goodwill impairment			37,874			—			37,874
Amortization of debt issuance cost			862			—			862
Accretion on available-for-sale investments, net			(22	)		—			(22	)
Gain on investments			(2,900	)		—			(2,900	)
Net loss on disposal of property, plant and equipment			458			—			458
Stock-based compensation expense			16,016			365			16,381
Deferred income taxes	ADJ 4		15,558			166			15,724
Inventory write down			24,313			—			24,313
Inventory reserves			25,546			—			25,546
Other, net			(2,942	)		—			(2,942	)
Change in operating assets and liabilities:						—			—
Accounts receivable, net			65,612			6,708			72,320
Other receivables			10,315			—			10,315
Income taxes receivable			(2,637	)		4,735			2,098
Inventory	ADJ 3		20,537			1,871			22,408
Prepaid expenses, other current assets and other assets			(29,883	)		(2,081	)		(31,964	)
Accounts payable			(91,907	)		—			(91,907	)
Accrued expenses and other liabilities			17,929			(6,612	)		11,317
Income taxes payable			(3,939	)		—			(3,939	)
Net cash (used in) provided by operating activities			(45,604	)		2,589			(43,015	)
Cash flows from investing activities:
Purchases of property, plant and equipment			(33,683	)		(2,654	)		(36,337	)
Purchases of intangibles - developed technology			(9,438	)		—			(9,438	)
Proceeds from sales and maturities of available-for-sale investments			10,567			—			10,567
Purchases of available-for-sale investments			(868	)		—			(868	)
Proceeds from beneficial interests in securitized accounts receivable			1,218			—			1,218
Net cash used in investing activities			(32,204	)		(2,654	)		(34,858	)
Cash flows from financing activities:
Tax withholdings related to stock-based compensation settlements			(6,458	)		—			(6,458	)
Proceeds from stock option exercises			540			—			540
Dividend payments			(21,237	)		—			(21,237	)
Proceeds from receivables purchase agreement			14,099			—			14,099
Proceeds from draw on revolving credit agreements			163,733			—			163,733
Repayment of revolving credit agreements			(64,987	)		—			(64,987	)
Redemption of redeemable non-controlling interest			(1,224	)		—			(1,224	)
Payment of debt issuance cost			(708	)		—			(708	)
Repayment of notes payable			(24,891	)		—			(24,891	)
Net cash provided by financing activities			58,867			—			58,867
Net decrease in cash and cash equivalents			(18,941	)		(65	)		(19,006	)
Effect of exchange rate changes			(2,536	)		65			(2,471	)
Cash, cash equivalents and restricted cash, beginning of year			108,644			—			108,644
Cash, cash equivalents and restricted cash, end of year		$	87,167		$	—		$	87,167
Supplemental disclosure of cash financing activities
Cash paid for interest		$	12,596		$	—		$	12,596
Cash paid for income taxes, net of refunds		$	18,552		$	—		$	18,552
Cash used in operating activities related to operating leases		$	9,682		$	—		$	9,682
Supplemental disclosure of non-cash investing activities:
Right-of-use assets obtained in exchange for lease obligations		$	17,865		$	—		$	17,865
Purchases of property, plant and equipment included in accounts payable		$	1,298		$	—		$	1,298
Redemption of redeemable non-controlling interest		$	371		$	—		$	371

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, instability in the financial services industry, currency fluctuations and political tensions as of December 31, 2024, 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.

Summary of Significant Accounting Policies

Cash and Cash Equivalents

Cash and cash equivalents represent demand deposits, money market funds and short-term investments classified as available-for-sale with original maturities of three months or less. We maintain depository investments with certain financial institutions. As of December 31, 2024 $72.4 million of our cash and cash equivalents, primarily certain domestic money market funds and foreign depository accounts, were in excess of government provided insured depository limits. Although these depository investments may exceed government insured depository limits, we have evaluated the credit worthiness of these applicable financial institutions and determined the risk of material financial loss due to the exposure of such credit risk to be minimal.

Fair Value of Financial Instruments

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Where available, fair value is based on observable market prices or parameters or derived from such prices or parameters. Where observable prices or inputs are not available, valuation models may be applied. Assets and liabilities recorded at fair value in our consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values.

The carrying amounts reported in the Consolidated Balance Sheets for cash and cash equivalents, accounts receivable and accounts payable approximate fair value due to the immediate or short-term maturity of these financial instruments.

The fair value measurements of our derivative instruments are determined using models that maximize the use of the observable market inputs including interest rate curves and both forward and spot prices for currencies, and are classified as Level II under the fair value hierarchy. The fair values of our derivatives are included in Note 10.

Investments with contractual maturities beyond one year may be classified as short-term based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Despite the long-term nature of their stated contractual maturities, we routinely buy and sell these securities and we believe we have the ability to quickly sell them to the remarketing agent, tender agent or issuer at par value plus accrued interest in the event we decide to liquidate our investment in a particular variable rate demand note. All income generated from these investments is recorded as interest income. We have not recorded any losses relating to variable rate demand notes.

Long-term investments is comprised of our deferred compensation plan assets, marketable equity securities and other equity investments. Marketable equity securities are reported at fair value as determined by the most recently traded price of the securities at the balance sheet date, although the securities may not be readily marketable due to the size of the available market. Any changes in fair value are recognized in net investment gain (loss). Realized gains and losses on sales of debt securities are computed under the specific identification method and are included in other income, net. See Note 4 for additional information.

Accounts Receivable

The Company records accounts receivable at amortized cost. Prior to establishing payment terms for a new customer, we evaluate the credit risk of the customer. Credit limits and payment terms established for new customers are re-evaluated periodically based on customer collection experience and other financial factors. As of December 31, 2024, no customer comprised more than 10% of our

total accounts receivable balance. As of December 31, 2023, a single customer comprised more than 10% of our total accounts receivable balance, which accounted for 12.2% of our total accounts receivable.

The Company regularly reviews the need for an allowance for credit losses related to our outstanding accounts receivable balances using the historical loss-rate method, as well as assessing asset-specific risks. The assessment of asset-specific risks included the evaluation of relevant available information, from internal and external sources, relating to current conditions that may affect a customer’s ability to pay, such as the customer’s current financial condition or credit rating by geographic location, as provided by a third party and/or by customer, if needed, and overall macro-economic conditions in which the customer operates. Based on this assessment, an allowance for credit losses would be recorded if the Company determined that, based on our historical write-offs, which have been immaterial, and such asset specific risks, there was risk in collectability of the full amount of any accounts receivable.

Accounts Receivable Factoring

Receivables Purchase Agreement

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. These transactions are accounted for in accordance with ASC Topic 860 and result in a reduction in accounts receivable because the Factoring Agreement transfers effective control over, and risk related to the receivables to the buyers. Trade accounts receivables balances sold are removed from the Consolidated Balance Sheets and cash received is reflected as cash flows provided by (used in) operating activities in the Consolidated Statements of Cash Flow. Factoring related interest expense is recorded to interest expense on the Consolidated Statements of Loss. On each sale date, the Factor retains from the sale price a default reserve, up to a required balance, which is held by the Factor in a reserve account and pledged to the Company. The Factor is entitled to withdraw from the reserve account the sale price of a defaulted receivable. The balance in the reserve account is included in other assets on the Consolidated Balance Sheets.

Previous Receivables Purchase Agreement

On December 19, 2023, the Company entered into a factoring agreement with a third-party financial institution to sell, on a revolving basis, undivided interests in the Company’s accounts receivable. The factoring agreement qualified for treatment as a secured borrowing with a pledge of collateral under Accounting Standards Codification ("ASC") Topic 810, Consolidations, as the Company was considered the primary beneficiary in a variable interest entity created to hold the factored receivables and the Company retained a residual claim on reserves related to the factored receivables. The receivables factored were carried in accounts receivable, less allowance for credit losses on the Consolidated Balance Sheets, the secured borrowings were carried on the Company’s Consolidated Balance Sheets as a current liability, in accounts payable, proceeds and repayments of the secured borrowings are reflected as cash flows (used in) provided by financing activities in the Consolidated Statements of Cash Flows and program fees are recorded in interest expense in the Company’s Consolidated Statements of Loss. The short-term liability classification of the secured borrowings was based on the estimated timing of the collection of the accounts receivable which were expected to be received within 12 months. The receivables purchase agreement was terminated on July 1, 2024 and there were no secured borrowings under this agreement as of December 31, 2024. See Note 2 for additional information.

Inventory

Inventory is carried at the lower of cost and estimated net realizable value, with cost being determined using the first-in, first-out method. Standard costs for material, labor and manufacturing overhead are used to value inventory and are updated at least quarterly. We establish reserves 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 consider historical usage, known trends, inventory age and market conditions. When we dispose of excess and obsolete inventories, the related disposals are charged against the inventory reserve. See Note 5 for additional information.

Property, Plant and Equipment

Property, plant and equipment, which is stated at cost, is depreciated using the straight-line method over the estimated useful lives of the assets. We depreciate building and land improvements from 5 to 39 years, office machinery and equipment from three to seven years, engineering machinery and equipment from three to seven years, and computer software from three to five years. Expenditures for repairs and maintenance are charged to expense as incurred. Major improvements that materially prolong the lives of the assets are capitalized. Gains and losses on the disposal of property, plant and equipment are recorded in operating loss. See Note 6 for additional information.

Assets Held for Sale

An asset is considered to be held for sale when all the following criteria are met: (i) management commits to a plan to sell the asset; (ii) the asset is available for immediate sale in its present condition; (iii) actions required to complete the sale of the asset have been initiated; (iv) sale of the asset is probable and the completed sale is expected to occur within one year; (v) it is unlikely that the disposal plan will

be significantly modified; and (vi) the asset is actively being marketed for sale at a price that is reasonable given its current market value.

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 December 31, 2024 and is separately recorded on the balance sheet.

Intangible Assets

Purchased intangible assets with finite lives are carried at cost less accumulated amortization. Amortization is recorded over the estimated useful lives of the respective assets. See Note 9 for additional information.

Impairment of Long-Lived Assets and Intangibles

Long-lived assets, such as property, plant and equipment, right of use lease assets and purchased intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset or asset group. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset or asset group.

During the first quarter of 2024, factors triggered a quantitative impairment assessment for the Network Solutions asset group. The long-lived assets associated with the Network Solutions asset group was approximately $361.5 million as of December 31, 2024

There were no impairment losses for long-lived assets and intangible assets during the years ended December 31, 2024, 2023 and 2022. See Note 9 for additional information.

Goodwill

Goodwill represents the excess purchase price over the fair value of net assets acquired. The Company’s annual impairment assessment is done at the reporting unit level, which we determined are generally the same as our operating segments, which are identified in Note 16 to the Consolidated Financial Statements. We review goodwill for impairment annually during the fourth quarter and also test for impairment between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of our reporting units below their carrying amount. Such events and circumstances may include among others: a significant adverse change in legal factors or in the general business climate; significant decline in our stock price and market capitalization; unanticipated competition; the testing for recoverability of a significant asset within the reporting unit; and an adverse action or assessment by a regulator. Any adverse change in these factors could have a significant impact on the recoverability of goodwill and could have a material impact on our consolidated financial statements.

The Company’s annual impairment test date is October 1, 2024. Based on our analysis, management concluded that there was no impairment of goodwill as of that date. Between the annual impairment date of October 1, 2024 and year-end December 31, 2024, there were no additional triggering events.

The Company recognized impairments of $297.4 million and $37.9 million during the years ended December 31, 2024 and 2023, respectively. No goodwill impairment charge was recorded during the year ended December 31, 2022. See Note 8 for additional information.

Other Non-Current Assets

Implementation costs incurred for hosting arrangements that are related to service contracts are capitalized and amortized over the term of the arrangement. Capitalized implementation costs totaled $0.1 million and $0.3 million as of December 31, 2024 and 2023, respectively, and are included in other non-current assets on the Consolidated Balance Sheets. In connection with the planned integration of information technology following the Business Combination, we determined that certain projects no longer fit our needs. The Company recognized impairment charges of $16.9 million during the year ended December 31, 2022 primarily related to capitalized implementation costs for a cloud computing arrangement. The impairment charges were determined based on actual costs incurred. During the year ended December 31, 2024 and 2023, no impairment charges were recognized. We depreciate capitalized implementation costs over various lives. Amortization expense was $0.1 million, $5.9 million and $3.9 million for the years ended December 31, 2024, 2023 and 2022, respectively, which is recorded almost entirely in selling, general and administrative expenses in the Consolidated Statements of Loss.

Pension Benefit Plan Obligations

The Company maintains a defined benefit pension plans covering employees in certain foreign countries. Pension benefit plan obligations are based on various assumptions used by our actuaries in calculating these amounts. These assumptions include discount rates, compensation rate increases, expected return on plan assets, retirement rates and mortality rates. Actual results that differ from the assumptions and changes in assumptions could affect future expenses and obligations. See Note 13 for additional information.

Lease Obligations

The Company has operating leases for office space, automobiles and various other equipment in the U.S. and in certain international locations. Other contracts, such as manufacturing agreements and service agreements, are reviewed to determine if they contain potential embedded leases. These other contracts are specifically reviewed to determine whether we have the right to substantially all of the economic benefit from the use of any specified assets or the right to direct the use of any specified assets, either of which would indicate the existence of a lease. Some of our leases include options to renew. For those leases that are reasonably assured to be renewed, we have included the option to extend as part of our right of use asset and lease liability. The exercise of lease renewal options is at our sole discretion. The depreciable life of leased assets and leasehold improvements are limited by the expected lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we elected to not separate lease and non-lease components. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants.

Stock-Based Compensation

The Company has two stock incentive plans from which stock options, performance stock units (“PSUs”), restricted stock units (“RSUs”) and restricted stock are available for grant to employees and directors. Costs related to these awards are recognized over their vesting periods.

Stock-based compensation expense recognized for the years ended December 31, 2024, 2023 and 2022 was approximately $16.0 million, $16.4 million and $28.3 million, respectively. See Note 3 for additional information.

Research and Development Costs

Research and development costs include compensation for engineers and support personnel, contracted services, depreciation and material costs associated with new product development, enhancement of current products and product cost reductions. We continually evaluate new product opportunities and engage in intensive research for product and software development efforts. Research and development costs totaled $221.5 million, $258.3 million and $173.8 million for the years ended December 31, 2024, 2023 and 2022, respectively.

Adtran Networks has arrangements with governmental entities for the purposes of obtaining funding for research and development activities. The Company classifies government grants received under these arrangements as a reduction to research and development expense incurred. For the years ended December 31, 2024, 2023 and 2022, the Company recognized $9.2 million, $5.2 million and $1.1 million, respectively, as a reduction of research and development expense.

Income Taxes

The provision for income taxes has been determined using the asset and liability approach of accounting for income taxes. Under this approach, deferred taxes represent the future tax consequences expected to occur when the reported amounts of assets and liabilities are recovered or paid. The provision for income taxes represents income taxes paid or payable for the current year plus the change in deferred taxes during the year. Deferred taxes result from the difference between financial and tax basis of our assets and liabilities and are adjusted for changes in tax rates and tax laws when such changes are enacted. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized.

In determining whether an uncertain tax position exists, the Company determines, based solely on its technical merits, whether the tax position is more likely than not to be sustained upon examination, and if so, a tax benefit is measured on a cumulative probability basis that is more likely than not to be realized upon the ultimate settlement. The Company recognizes interest and penalties related to unrecognized tax benefits through interest expense and income tax expense, respectively.

Foreign Currency

Transactions with customers that are denominated in foreign currencies are recorded using the appropriate exchange rates from throughout the year. Assets and liabilities denominated in foreign currencies are remeasured at the balance sheet dates using the closing rates of exchange between those foreign currencies and the functional currency with any transaction gains or losses reported in other income, net. Our primary exposures to foreign currency exchange rate movements are with our German and United Kingdom subsidiaries, whose functional currencies are the euro and the British pound sterling. Adjustments resulting from translating financial statements of international subsidiaries are recorded as a component of accumulated other comprehensive income.

Revenue

Revenue is measured based on the consideration expected to be received in exchange for transferring goods or providing services to a customer and as performance obligations under the terms of the contract are satisfied. Generally, this occurs with the transfer of control of a product to the customer. For transactions where there are multiple performance obligations, individual products and services are accounted for separately if they are distinct (if a product or service is separately identifiable from other items and if a customer can

benefit from it on its own or with other resources that are readily available to the customer). The consideration, including any discounts, is allocated between separate products and services based on their stand-alone selling prices. Stand-alone selling prices are determined based on the prices at which the separate products and services are sold and are allocated based on each item’s relative value to the total value of the products and services in the arrangement. For items that are not sold separately, we estimate stand-alone selling prices primarily using the “expected cost plus a margin” approach. Payment terms are generally 30 days in the U.S. and typically longer in many geographic markets outside the U.S. Shipping fees collected are recorded as revenue and the related cost is included in cost of revenue. Revenue, value-added and other taxes collected concurrently with revenue-producing activities are excluded from revenue. Incremental costs of obtaining a contract, that are recoverable, are capitalized and amortized over the period that the related revenue is recognized if greater than one year. We have elected to account for shipping fees paid as a cost of fulfilling the related contract. We have also elected to apply the practical expedient related to the incremental costs of obtaining contracts and recognize those costs as an expense when incurred if the amortization period of the assets is one year or less. These costs are included in selling, general and administrative expenses. Capitalized costs with an amortization period greater than one year were immaterial.

Revenue is generated by two reportable segments: Network Solutions and Services & Support.

Network Solutions Segment - Includes hardware products and software defined next-generation virtualized solutions used in Service Provider or business networks, as well as prior generation products. The majority of the revenue from this segment is from hardware revenue.

Hardware and Software Revenue

Revenue from hardware sales is recognized when control is transferred to the customer, which is generally when the products are shipped. Shipping terms are generally FOB shipping point. Revenue from software license sales is recognized at delivery and transfer of control to the customer. Revenue is recognized net of estimated discounts and rebates using historical trends. Customers are typically invoiced when control is transferred and revenue is recognized. Our products generally include assurance-based warranties of 90 days to five years for product defects, which are accrued at the time products are delivered.

Services & Support Segment - Includes a complete portfolio of maintenance, network implementation and solutions integration and managed services, which include hosted cloud services and subscription services to complement our Network Solutions segment.

Maintenance Revenue

Our maintenance service periods range from one month to five years. Customers are typically invoiced and pay for maintenance services at the beginning of the maintenance period. We recognize revenue for maintenance services on a straight-line basis over the maintenance period as our customers benefit evenly throughout the contract term and deferred revenue, when applicable, are recorded in current and non-current unearned revenue.

Network Implementation Revenue

The Company recognizes revenue for network implementation, which primarily consists of engineering, execution and enablement services at a point in time when each performance obligation is complete. If we have recognized revenue but have not billed the customer, the right to consideration is recognized as a contract asset that is included in other receivables on the Consolidated Balance Sheet. The contract asset is transferred to accounts receivable when the completed performance obligation is invoiced to the customer.

See Notes 2 and 16 for additional information on reportable segments.

Unearned Revenue

Unearned revenue primarily represents customer billings on maintenance service programs and unearned revenue related to multiple element contracts where we still have contractual obligations to our customers. We currently offer maintenance contracts ranging from one month to five years. Revenue attributable to maintenance contracts is recognized on a straight-line basis over the related contract term. In addition, we provide software maintenance and a variety of hardware maintenance services to customers under contracts with terms up to ten years. When we defer revenue related to multiple performance obligations where we still have contractual obligations, we also defer the related costs. Current deferred costs are included in prepaid expenses and other current assets on the accompanying Consolidated Balance Sheets and totaled $2.2 million and $2.1 million as of December 31, 2024 and 2023, respectively. Non-current deferred costs included in other non-current assets on the accompanying Consolidated Balance Sheets were less than $0.1 million as of December 31, 2024 and December 31, 2023.

Redeemable Non-Controlling Interest

As of December 31, 2024 and 2023, the non-controlling Adtran Networks stockholders’ equity ownership percentage in Adtran Networks was approximately 33.0% and 34.7%, respectively.

As a result of the effectiveness of the DPLTA on January 16, 2023, the Adtran Networks shares, representing the equity interest in Adtran Networks held by holders other than the Company, can be tendered at any time and are, therefore, redeemable and must be

classified outside stockholders’ equity. Therefore, the permanent equity noncontrolling interest balance was reclassified to redeemable non-controlling interest (RNCI) on January 16, 2023 and was remeasured to fair value based on the trading market price of the Adtran Networks shares.

Subsequently, the carrying value of the RNCI is adjusted to its maximum redemption value at each reporting date when the maximum redemption value is greater than the initial carrying amount of the RNCI. For the period of time that the DPLTA is in effect, the RNCI will continue to be presented as RNCI outside of stockholders’ equity in the Consolidated Balance Sheets. See Note 15 for additional information on RNCI.

Loss per Share

Loss per common share and loss per common share assuming dilution are based on the weighted average number of common shares and, when dilutive, common equivalent shares outstanding during the year. See Note 19 for additional information.

Loss per common share attributable to ADTRAN Holdings, Inc. - basic and diluted - reflects a $3.0 million effect of redemption of RNCI for the year ended December 31, 2024. See Note 19 for additional information.

Recent Accounting Pronouncements Not Yet Adopted

In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("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 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 in the first annual period 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.

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

In November 2023, the FASB issued ASU 2023-7, "Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures", which is intended to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses, allowing financial statement users to better understand the components of a segment's profit or loss to assess potential future cash flows for each reportable segment and the entity as a whole. The amendments expand a public entity's segment disclosures by requiring disclosure of significant segment expenses that are regularly provided to the chief operating decision maker ("CODM"), clarifying when an entity may report one or more additional measures to assess segment performance, requiring enhanced interim disclosures, providing new disclosure requirements for entities with a single reportable segment, and requiring other new disclosures. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024.

The Company adopted the new standard on January 1, 2024. The adoption of this standard resulted in additional footnote disclosures. The adoption of this standard did not have a material impact on our Consolidated Balance Sheet, Consolidated Statement of Income or Consolidated Statement of Cash Flows. See Note 16 for additional information.

There have been no other recently adopted accounting pronouncements that are expected to have a material effect on the 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 Balance Sheet and Consolidated Statement of Cash Flows for the fiscal year ended December 31, 2023, to reclassify between Property, Plant and Equipment and Intangible Assets.