Exhibit 99.1

ADTRAN Holdings, Inc. reports second quarter 2023 results

HUNTSVILLE, AL — (August 06, 2023) — ADTRAN Holdings, Inc. (NASDAQ: ADTN and FSE: QH9) (“ADTRAN Holdings” or the “Company”) today announced its financial results for the second quarter of 2023. For the quarter, revenue was $327.4 million, up 90% year-over-year and 1% quarter-over-quarter. Net loss attributable to the Company for the second quarter of 2023 was $33.3 million, down 1,655% year-over-year and up 3% quarter-over-quarter. Consequently, diluted loss per share attributable to the Company for the quarter was $0.43, down by 1,175% year-over-year and up 2% quarter-over-quarter. Non-GAAP net income attributable to the Company was $0.1 million, down 99% year-over-year and up 102% quarter-over-quarter. Consequently, non-GAAP diluted earnings per share attributable to the Company was $0.00, down 99% year-over-year and up 102% quarter-over-quarter. Non-GAAP net loss and non-GAAP diluted loss per share exclude acquisition related expenses, amortization, adjustments (consisting of intangible amortization of backlog, developed technology, customer relationships, and trade names acquired in connection with business combinations and amortization of inventory fair value adjustments), stock-based compensation expense, amortization of pension actuarial losses, deferred compensation adjustments, integration expenses, restructuring expenses, changes in valuation allowance related to our deferred tax assets, and the tax effect of these adjustments to net (loss) income. The reconciliations between the non-GAAP net loss measures presented herein and the respective equivalent GAAP financial measures are set forth in the tables provided below.

ADTRAN Holdings Chairman and Chief Executive Officer Tom Stanton stated, “Our Q2 2023 results were in line with our expectations. Although new customer acquisitions remain near an all-time high, we anticipate the second half of 2023 will continue to present challenges due to customers optimizing inventory and the macroeconomic environment. Nevertheless, we continue to believe that we are in the early stage of an unprecedented investment cycle and Adtran Holdings is well positioned to be one of the largest beneficiaries.”

The Company also announced that its Board of Directors declared a cash dividend for the second quarter of 2023. The quarterly cash dividend of $0.09 per common share is to be paid to the Company’s stockholders of record as of the close of business on August 21, 2023. The ex-dividend date is August 20, 2023, and the payment date will be September 5, 2023.

The Company confirmed that it will hold a conference call to discuss its second quarter results on Tuesday, August 8, 2023, at 9:30 a.m. Central Time, or 4:30 p.m. Central European Summer Time. ADTRAN Holdings will webcast this conference call. To listen, simply visit our Investor Relations site at investors.adtran.com approximately 10 minutes prior to the start of the call, click on the event “ADTRAN Holdings Releases 2nd Quarter 2023 Financial Results and Earnings Call”, and click on the webcast link.

An online replay of the Company’s conference call, as well as the transcript of the Company’s conference call, will be available on the Investor Relations site approximately 24 hours following the call and will remain available for at least 12 months. For more information, visit investors.adtran.com or email investor.relations@adtran.com.

Cautionary Note Regarding Forward-Looking Statements

Statements contained in this press release which are not historical facts, such as those relating to strategy, outlook and financial guidance, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can also generally be identified by the use of words such as “believe,” “expect,” “intend,” “estimate,” “anticipate,” “will,” “may,” “could” and similar expressions. In addition, ADTRAN Holdings, through its senior management, may from time to time make forward-looking public statements concerning the matters described herein. All such projections and other forward-looking information speak only as of the date hereof, and ADTRAN Holdings undertakes no duty to publicly update or revise such forward-looking information, whether as a result of new information, future events, or otherwise, except to the extent as may be required by law. All such forward-looking statements are necessarily estimates and reflect management’s best judgment based upon current information. Actual events or results may differ materially from those anticipated in these forward-looking statements as a result of a variety of factors. While it is impossible to identify all such factors, factors which could cause actual events or results to differ materially from those estimated by ADTRAN Holdings include, but are not limited to: (i) risks and uncertainties related to manufacturing and supply chain constraints; (ii) risks and uncertainties related to the completed business combination between the Company, ADTRAN, Inc. (“ADTRAN”) and Adtran Networks SE (“Adtran Networks”), formerly ADVA Optical Networks SE, including risks related to the ability to successfully integrate ADTRAN’s and Adtran Networks’ businesses, the disruption of management time from ongoing business operations due to integration efforts following the business combination, and the risk that ADTRAN Holdings may be unable to achieve expected synergies or that it may take longer or be more costly than expected to achieve those synergies; (iii) the risk of fluctuations in revenue, including due to lengthy sales and approval processes required by major and other service providers for new products and changes in customer demand, as well as tighter inventory management of ADTRAN Holdings’ customers; (iv) the risk posed by potential breaches of information systems and cyber-attacks; (v) the risk that ADTRAN Holdings may not be able to effectively compete, including through product improvements and development; (vi) risks related to ongoing patent litigation; and (vii) other risks set forth in ADTRAN Holdings’ public filings made with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended December 31, 2022, as well as its Form 10-Q for the quarter ended March 31, 2023 filed with the SEC.

Explanation of Use of Non-GAAP Financial Measures

Set forth in the tables below are reconciliations of gross profit, gross margin, operating expenses, operating (loss) income, other income (expense), net (loss) income inclusive of the non-controlling interest, net (loss) income attributable to the Company, net loss attributable to the non-controlling interest, and (loss) earnings per share - basic and diluted, attributable to the Company, in each case as reported based on generally accepted accounting principles in the United States (“GAAP”), to non-GAAP gross profit, non-GAAP gross margin, non-GAAP operating expenses, non-GAAP operating income (loss), non-GAAP other (expense) income, non-GAAP net (loss) income inclusive of the non-controlling interest, non-GAAP net income (loss) attributable to the Company, non-GAAP net loss attributable to the non-controlling interest, and non-GAAP earnings (loss) per share - basic and diluted, attributable to the Company, respectively. Such non-GAAP measures exclude acquisition related expenses, amortization and adjustments (consisting of intangible amortization of backlog, developed technology, customer relationships, and trade names acquired in connection with business combinations and amortization of inventory fair value adjustments), stock-based compensation expense, amortization of pension actuarial losses, deferred compensation adjustments, integration expenses, restructuring expenses, asset impairments, changes in valuation allowance related to our deferred tax assets, and the tax effect of these adjustments to net income. These measures are used by management in our ongoing planning and annual budgeting processes. Additionally, we believe the presentation of these non-GAAP measures when combined with the presentation of the most directly comparable GAAP financial measure, is beneficial to the overall understanding of ongoing operating performance of the Company.

These non-GAAP financial measures are not prepared in accordance with, or an alternative for, GAAP and therefore should not be considered in isolation or as a substitution for analysis of our results as reported under GAAP. Additionally, our calculation of non-GAAP measures may not be comparable to similar measures calculated by other companies.

About Adtran

ADTRAN Holdings, Inc. (NASDAQ: ADTN and FSE: QH9) is the parent company of Adtran, Inc., a leading global provider of open, disaggregated networking and communications solutions that enable voice, data, video and internet communications across any network infrastructure. From the cloud edge to the subscriber edge, Adtran empowers communications service providers around the world to manage and scale services that connect people, places and things. Adtran solutions are used by service providers, private enterprises, government organizations and millions of individual users worldwide. ADTRAN Holdings, Inc. is also the largest shareholder of Adtran Networks SE, formerly ADVA Optical Networking SE. Find more at Adtran, LinkedIn and Twitter.

Published by

ADTRAN Holdings, Inc.

www.adtran.com

For media

Gareth Spence

+44 1904 699 358

public-relations@adva.com

For investors

Steven Williams

+49 89 890 665 918

investor.relations@adtran.com

Condensed Consolidated Balance Sheets

(Unaudited)

(In thousands)

Condensed Consolidated Statements of (Loss) Income

(Unaudited)

(In thousands, except per share amounts)

Condensed Consolidated Statements of Cash Flows

(Unaudited)

(In thousands)

Supplemental Information

Reconciliation of Gross Profit and Gross Margin to

Non-GAAP Gross Profit and Non-GAAP Gross Margin

(Unaudited)

(In thousands)

Supplemental Information

Reconciliation of Operating Expenses to Non-GAAP Operating Expenses

(Unaudited)

(In thousands)

Supplemental Information

Reconciliation of Operating (Loss) Income to Non-GAAP Operating Income (Loss)

(Unaudited)

(In thousands)

Supplemental Information

Reconciliation of Other Income (Expense) to Non-GAAP Other Expense

(Unaudited)

(In thousands)

Supplemental Information

Reconciliation of Net (Loss) Income inclusive of Non-Controlling Interest to

Non-GAAP Net (Loss) Income inclusive of Non-Controlling Interest

(Unaudited)

and

Reconciliation of Net Loss attributable to Non-Controlling Interest to

Non-GAAP Net Loss attributable to Non-Controlling Interest

(Unaudited)

and

Reconciliation of Net (Loss) Income attributable to ADTRAN Holdings, Inc. and

(Loss) Earnings per Common Share attributable to ADTRAN Holdings, Inc. – Basic and Diluted to

Non-GAAP Net Income (Loss) attributable to ADTRAN Holdings, Inc. and

Non-GAAP Earnings (Loss) per Common Share attributable to ADTRAN Holdings, Inc. – Basic and Diluted

(Unaudited)

(In thousands, except per share amounts)

Exhibit 99.2

Ad-hoc notification pursuant to Article 17 of Regulation (EU) No. 596/2014

ADTRAN Holdings, Inc.: Guidance for the third quarter of 2023 expected to deviate from analyst consensus

Huntsville, Alabama (United States of America). August 7, 2023

Based on the financial results for the second quarter of 2023 and the first half year of 2023, ADTRAN Holdings, Inc. (“ADTRAN Holdings” or the “Company”) (NASDAQ: ADTN; FSE: QH9), expects the Company’s guidance range for the third quarter 2023 to deviate from analyst consensus as follows:

The expected guidance range for the third quarter 2023 is based on the following financial results for the second quarter of 2023 which were within our guidance.

The information contained in this ad hoc notification is solely based on unaudited condensed consolidated results. Non-GAAP operating margin (which is calculated as non-GAAP operating income divided by revenue) is a non-GAAP financial measure. A reconciliation between GAAP operating loss for the second quarter and non-GAAP operating income is set forth in the table provided below. In addition, the Company has provided third quarter earnings guidance with regard to non-GAAP operating margin. This measure excludes from the corresponding GAAP financial measure the effect of adjustments as described below under “Explanation of Use of Non-GAAP Financial Measures.” The Company has not provided a reconciliation of such non-GAAP guidance to guidance presented on a GAAP basis because it cannot predict and quantify without unreasonable effort all of the adjustments that may occur during the period.

Cautionary Note Regarding Forward-Looking Statements

Statements contained in this ad hoc notification which are not historical facts, such as those relating to strategy, outlook and financial guidance, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can also generally be identified by the use of words such as “believe,” “expect,” “intend,” “estimate,” “anticipate,” “will,” “may,” “could” and similar expressions. In addition, ADTRAN Holdings, through its senior management, may from time to time make forward-looking public statements concerning the matters described herein. All such projections and other forward-looking information speak only as of the date hereof, and ADTRAN Holdings undertakes no duty to publicly update or revise such forward-looking information, whether as a result of new information, future events, or otherwise, except to the extent as may be required by law. All such forward-looking statements are necessarily estimates and reflect management’s best judgment based upon current information. Actual events or results may differ materially from those anticipated in these forward-looking statements as a result of a variety of factors.

While it is impossible to identify all such factors, factors which could cause actual events or results to differ materially from those estimated by ADTRAN Holdings include, but are not limited to: (i) risks and uncertainties related to manufacturing and supply chain constraints; (ii) risks and uncertainties related to the completed business combination between the Company, ADTRAN, Inc. (“ADTRAN”) and Adtran Networks SE (“Adtran Networks”), including risks related to the ability to successfully integrate ADTRAN’s and Adtran Networks’ businesses, the disruption of management time from ongoing business operations due to integration efforts following the business combination, and the risk that ADTRAN Holdings may be unable to achieve expected synergies or that it may take longer or be more costly than expected to achieve those synergies; (iii) the risk of fluctuations in revenue due to lengthy sales and approval processes required by major and other service providers for new products, as well as tighter inventory management of ADTRAN Holdings’ customers; (iv) the risk posed by potential breaches of information systems and cyber-attacks; (v) the risk that ADTRAN Holdings may not be able to effectively compete, including through product improvements and development; (vi) risks related to ongoing patent litigation; and (vii) other risks set forth in ADTRAN Holdings’ public filings made with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended December 31, 2022, as well as its Form 10-Q for the quarter ended March 31, 2023.

Explanation of Use of Non-GAAP Financial Measures

Set forth in the table below is a reconciliation of operating loss as reported based on generally accepted accounting principles in the United States (“GAAP”), to non-GAAP operating income. Such non-GAAP measure excludes acquisition related expenses, amortization and adjustments (consisting of intangible amortization of backlog, inventory fair value adjustments, developed technology, customer relationships, and trade names acquired in connection with business combinations), stock-based compensation expense, pension adjustments, restructuring expenses, integration expenses, and deferred compensation adjustments. This measure is used by management in our ongoing planning and annual budgeting processes. Additionally, we believe the presentation of non-GAAP operating income, when combined with the presentation of the most directly comparable GAAP financial measure, GAAP operating loss, is beneficial to the overall understanding of ongoing operating performance of the Company. This non-GAAP financial measure is not prepared in accordance with, or as an alternative for, GAAP and therefore should not be considered in isolation or as a substitution for analysis of our results as reported under GAAP. Additionally, our calculation of non-GAAP measures may not be comparable to similar measures calculated by other companies.

Reconciliation of GAAP Operating Loss to Non-GAAP Operating Income

(Unaudited, in millions)

Published by

Adtran Holdings, Inc.

www.adtran.com

For media

Gareth Spence

+44 1904 699 358

public-relations@adva.com

Notifying person and contact for investors

Steven Williams

+49 89 890 665 918

investor.relations@adtran.com