ADTRAN Holdings Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule

14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant ☒ Filed by a party other than the Registrant ☐

Check the appropriate box:

ADTRAN Holdings, Inc.

(Name of Registrant as Specified in its Charter)

Not applicable.

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

NOTICE OF 2024 ANNUAL MEETING

AND

PROXY STATEMENT

March 27, 2024

Dear Stockholder:

You are cordially invited to attend the 2024 Annual Meeting of Stockholders of ADTRAN Holdings, Inc. to be held on Wednesday, May 8, 2024, at 10:30 a.m., Central Time. We are pleased to announce that this year’s Annual Meeting will be a virtual meeting conducted by live webcast on the Internet. You will be able to attend and participate in the meeting by visiting www.virtualshareholdermeeting.com/ADTN2024 and entering the 16-digit control number included on your Notice of Internet Availability of Proxy Materials (the “Notice”) or on your proxy card if you receive the proxy materials by mail. You will not be able to attend the Annual Meeting in person.

The attached Notice of Annual Meeting of Stockholders and Proxy Statement describe the formal business to be transacted at the meeting. During the meeting, we also will report on Adtran’s operations during the past year and our plans for the future.

We have elected to take advantage of Securities and Exchange Commission rules that allow issuers to furnish proxy materials to their stockholders on the Internet. We believe that the rules will allow us to provide our stockholders with the information they need, while lowering the costs of delivery and reducing the environmental impact of the annual meeting.

Your vote, whether during the virtual meeting on May 8, 2024 or by proxy, is important. Please review the instructions on each of your voting options described in the accompanying proxy materials and the Notice you received in the mail. If you are unable to participate in the virtual meeting, I urge you to vote as soon as possible.

Sincerely,

THOMAS R. STANTON

Chairman of the Board

901 EXPLORER BOULEVARD

HUNTSVILLE, ALABAMA 35806

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD WEDNESDAY, MAY 8, 2024

NOTICE HEREBY IS GIVEN that the 2024 Annual Meeting of Stockholders (the “Annual Meeting”) of ADTRAN Holdings, Inc. (the “Company”) will be held on Wednesday, May 8, 2024, at 10:30 a.m., Central Time, via live webcast. You can participate in the meeting by visiting www.virtualshareholdermeeting.com/ADTN2024 and entering the 16-digit control number included on your Notice or proxy card. If you hold your shares through an intermediary, such as a bank or broker, and do not have a control number, please contact the bank or broker. Please log in to the website by 10:15 a.m., Central Time, on the day of the meeting. There is no physical location for the Annual Meeting.

The Annual Meeting is being held for the purposes of considering and voting upon:

The Board of Directors recommends that you vote FOR each of the eight director nominees; FOR the adoption of the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan; FOR the adoption of the ADTRAN Holdings, Inc. 2024 Directors Stock Plan; FOR the approval on an advisory basis of the compensation of the Company’s NEOs; and FOR the ratification of the appointment of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2024. The Annual Meeting may be adjourned from time to time without notice other than announcement at the meeting or at adjournments thereof, and any business for which notice is hereby given may be transacted at any such adjournment.

Information relating to the above matters is set forth in the attached Proxy Statement. Stockholders of record at the close of business on March 11, 2024, are entitled to receive notice of and to vote during the Annual Meeting and any adjournments thereof.

Whether or not you plan to participate in the Annual Meeting, we urge you to review these materials carefully, which are available at https://materials.proxyvote.com/00486H. We also encourage you to vote by (i) following the instructions on the notice that you received from your broker, bank or other nominee if your shares are held beneficially in “street name” or (ii) one of the following means if your shares are registered directly in your name with the Company’s transfer agent:

You can submit questions in advance of the Annual Meeting by visiting www.proxyvote.com, entering your 16-digit control number, and using the “Questions for Management” feature. You can submit questions during the Annual Meeting by following the instructions on the meeting website. Management will answer pertinent questions in the “Investor Resources” section of our website at https://investors.adtran.com. The questions and answers will be available as soon as practicable after the Annual Meeting and will remain available for thirty (30) days after posting.

By order of the Board of Directors,

ULRICH DOPFER

Senior Vice President of Finance, Chief Financial Officer, Corporate Secretary and Treasurer

Huntsville, Alabama

March 27, 2024

TABLE OF CONTENTS

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PROXY STATEMENT FOR THE ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD WEDNESDAY, MAY 8, 2024

This Proxy Statement, along with the accompanying Notice of Annual Meeting of Stockholders, contains information about the 2024 Annual Meeting of Stockholders (the “Annual Meeting”) of ADTRAN Holdings, Inc. (the “Company”), including any adjournments or postponements of the Annual Meeting. The Annual Meeting will be held on Wednesday, May 8, 2024 at 10:30 a.m., Central Time. We are pleased to announce that this year’s Annual Meeting will be a virtual meeting conducted by live webcast on the Internet. You will be able to attend and participate in the meeting by visiting www.virtualshareholdermeeting.com/ADTN2024 and entering the 16-digit control number included on your Notice of Internet Availability of Proxy Materials (the “Notice”) or on your proxy card if you receive the proxy materials by mail. If you hold your shares through an intermediary, such as a bank or broker, and do not have a control number, please contact the bank or broker. Please log in to the website by 10:15 a.m., Central Time, on the day of the meeting. You may vote during the Annual Meeting by following the instructions available on the meeting website. There is no physical location for the Annual Meeting.

You can submit questions in advance of the Annual Meeting by visiting www.proxyvote.com, entering your 16-digit control number, and using the “Questions for Management” feature. You can submit questions during the Annual Meeting by following the instructions on the meeting website. Management will answer pertinent questions in the “Investor Resources” section of our website at https://investors.adtran.com. The questions and answers will be available as soon as practicable after the Annual Meeting and will remain available for thirty (30) days after posting.

We are providing this Proxy Statement to the stockholders of the Company in connection with the solicitation of proxies by our Board of Directors to be voted during the Annual Meeting and at any adjournments of that meeting.

On or about March 27, 2024, we began sending the Notice to all stockholders entitled to vote in advance of or during the virtual Annual Meeting. We encourage all of our stockholders to vote on the proposals presented, and we hope the information contained in this document will help you decide how you wish to vote.

Important Notice Regarding the Availability of Proxy Materials for the

Annual Meeting of Stockholders to be held on May 8, 2024:

This Notice, the Proxy Statement and the 2023 Annual Report to Stockholders of ADTRAN Holdings, Inc. are available free of charge to view, print and download at https://materials.proxyvote.com/00486H.

Additionally, you can find a copy of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023, including financial statements and schedules thereto, on the website of the Securities and Exchange Commission (the “SEC”) at www.sec.gov, or in the “SEC Filings” section of our website at https://investors.adtran.com. You may also obtain a printed copy of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023, including financial statements and schedules thereto, free of charge, from us by sending a written request to: ADTRAN Holdings, Inc., Attn: Corporate Secretary, 901 Explorer Boulevard, Huntsville, Alabama 35806. Exhibits will be provided upon written request.