Proxy Results, Amendments to Bylaws (Form 8-K)

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

At the Annual Meeting of Stockholders held by ADTRAN Holdings, Inc. (the "Company") on May 13, 2026 (the "2026 Annual Meeting"), the Company's stockholders approved an amendment (the "Charter Amendment") to the Company's Amended and Restated Certificate of Incorporation (the "Charter"). As further described in Proposal 2 of the Company's definitive proxy statement filed with the Securities and Exchange Commission on March 27, 2026, the Charter Amendment provides for the elimination of monetary liability (i.e., exculpation) of certain officers of the Company in the limited circumstances permitted under Delaware law and made certain additional changes to Section 7.1 of the Charter. The Charter Amendment became effective upon the filing of a Certificate of Amendment (the "Certificate of Amendment") with the Secretary of State of the State of Delaware on May 13, 2026.

The foregoing summary is not complete and is qualified in its entirety by reference to the full text of the Certificate of Amendment, a copy of which is filed as Exhibit 3.1 and incorporated by reference herein.

Item 5.07 Submission of Matters to a Vote of Security Holders.

At the 2026 Annual Meeting, the Company's stockholders (i) elected six directors to serve on the board of directors of the Company (the "Board") for a one-year term expiring at the 2027 Annual Meeting of Stockholders and until their successors have been duly elected and qualified (Proposal 1); (ii) approved the Charter Amendment to limit the liability of certain officers as permitted by Delaware law and to make certain other changes to Section 7.1 thereof (Proposal 2); (iii) approved, on an advisory basis, the compensation of the Company's named executive officers (Proposal 3); and (iv) ratified the appointment of PricewaterhouseCoopers LLP as the independent registered public accounting firm of the Company for the fiscal year ending December 31, 2026 (Proposal 4). The voting results for these proposals are presented in the tables below:

Proposal 1 - Election of Directors

Proposal 2 - Amendment to Amended and Restated Certificate of Incorporation to Limit the Liability of Certain Officers as Permitted by Delaware Law and to Make Certain Other Changes to Section 7.1 Thereof

Proposal 3 - Advisory Vote Regarding the Compensation of the Company's Named Executive Officers

Proposal 4 - Ratification of the Appointment of PricewaterhouseCoopers LLP as the Company's Independent Registered Public Accounting Firm for the Fiscal Year Ending December 31, 2026

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits