ADTRAN (ADTN) investor relations material

Executive summary

• The 2026 Annual Meeting will be held virtually on May 13, 2026, with shareholders able to participate and vote online using a control number provided in their proxy materials.

• Proxy materials are distributed electronically to reduce costs and environmental impact, with printed copies available upon request.

• Shareholders of record as of March 16, 2026, are entitled to vote on key proposals, including director elections, amendments to the certificate of incorporation, executive compensation, and auditor ratification.

Voting matters and shareholder proposals

• Shareholders will vote on electing six directors, approving an amendment to limit officer liability, an advisory say-on-pay vote, and ratifying PricewaterhouseCoopers LLP as auditor.

• The board recommends voting FOR all proposals.

• Shareholder proposals for the 2027 meeting must be submitted by November 27, 2026, for inclusion in the proxy statement.

Board of directors and corporate governance

• The board will be reduced to six members, with five considered independent after the meeting.

• Annual board and committee evaluations are conducted, and there are no classified boards or poison pills.

• Stock ownership guidelines require non-employee directors to hold shares equal to at least three times their annual cash retainer.

• The board has Audit, Compensation, Nominating and Corporate Governance, and Sustainability Committees, all composed of independent directors.