Adtran Holdings, Inc.: Release according to Article 40, Section 1 of the WpHG [the German Securities Trading Act] with the objective of Europe-wide distribution

EQS Voting Rights Announcement: Adtran Holdings, Inc. Adtran Holdings, Inc.: Release according to Article 40, Section 1 of the WpHG [the German Securities Trading Act] with the objective of Europe-wide distribution 06.11.2025 / 21:30 CET/CEST Dissemination of a Voting Rights Announcement transmitted by EQS News - a service of EQS Group. The issuer is solely responsible for the content of this announcement. Notification of Major Holdings 1. Details of issuer Name: Adtran Holdings, Inc. Street: 901 Explorer Boulevard Postal code: 35806 City: Huntsville United States Legal Entity Identifier (LEI): 549300VV36J86CRRWF77 2. Reason for notification X Acquisition/disposal of shares with voting rights   Acquisition/disposal of instruments   Change of breakdown of voting rights X Other reason: voluntary group notification with triggered threshold on subsidiary level 3. Details of person subject to the notification obligation Legal entity: BlackRock, Inc. City of registered office, country: Wilmington, Delaware, United States of America (USA) 4. Names of shareholder(s) holding directly 3% or more voting rights, if different from 3. 5. Date on which threshold was crossed or reached: 03 Nov 2025 6. Total positions   % of voting rights attached to shares (total of 7.a.) % of voting rights through instruments (total of 7.b.1 + 7.b.2) Total of both in % (7.a. + 7.b.) Total number of voting rights pursuant to Sec. 41 WpHG New 6.98 % 6.001 % 12.98 % 80115995 Previous notification 7.40 % 5.46 % 12.86 % / 7. Details on total positions a. Voting rights attached to shares (Sec. 33, 34 WpHG) ISIN Absolute In %   Direct (Sec. 33 WpHG) Indirect (Sec. 34 WpHG) Direct (Sec. 33 WpHG) Indirect (Sec. 34 WpHG) US00486H1059 0 5592273 0 % 6.98 % Total 5592273 6.98 % b.1. Instruments according to Sec. 38 (1) no. 1 WpHG Type of instrument Expiration or maturity date Exercise or conversion period Voting rights absolute Voting rights in % Lent Securities (right to recall) N/A N/A 2523056 3.15 %     Total 2523056 3.15 % b.2. Instruments according to Sec. 38 (1) no. 2 WpHG Type of instrument Expiration or maturity date Exercise or conversion period Cash or physical settlement Voting rights absolute Voting rights in % Contract for Difference N/A N/A Cash 2284349 2.85 %       Total 2284349 2.85 % 8. Information in relation to the person subject to the notification obligation   Person subject to the notification obligation is not controlled nor does it control any other undertaking(s) that directly or indirectly hold(s) an interest in the (underlying) issuer (1.). X Full chain of controlled undertakings starting with the ultimate controlling natural person or legal entity: Name % of voting rights (if at least 3% or more) % of voting rights through instruments (if at least 5% or more) Total of both (if at least 5% or more) BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % Trident Merger LLC % % % BlackRock Investment Management, LLC % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock Capital Holdings, Inc. % % % BlackRock Advisors, LLC % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % Trident Merger LLC % % % BlackRock Investment Management, LLC % % % Amethyst Intermediate LLC % % % Aperio Holdings LLC % % % Aperio Group, LLC % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BlackRock Canada Holdings ULC % % % BlackRock Asset Management Canada Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock Holdco 4, LLC % % % BlackRock Holdco 6, LLC % % % BlackRock Delaware Holdings Inc. % % % BlackRock Fund Advisors % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock Holdco 4, LLC % % % BlackRock Holdco 6, LLC % % % BlackRock Delaware Holdings Inc. % % % BlackRock Institutional Trust Company, National Association % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Australia Holdco Pty. Ltd. % % % BlackRock Investment Management (Australia) Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock (Singapore) Holdco Pte. Ltd. % % % BlackRock HK Holdco Limited % % % BlackRock Asset Management North Asia Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock (Singapore) Holdco Pte. Ltd. % % % BlackRock HK Holdco Limited % % % BlackRock Lux Finco S. a r.l. % % % BlackRock Japan Holdings GK % % % BlackRock Japan Co., Ltd. % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Holdco 3, LLC % % % BlackRock Cayman 1 LP % % % BlackRock Cayman West Bay Finco Limited % % % BlackRock Cayman West Bay IV Limited % % % BlackRock Group Limited % % % BlackRock International Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Holdco 3, LLC % % % BlackRock Cayman 1 LP % % % BlackRock Cayman West Bay Finco Limited % % % BlackRock Cayman West Bay IV Limited % % % BlackRock Group Limited % % % BlackRock Luxembourg Holdco S.a.r.l. % % % BlackRock Asset Management Ireland Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Holdco 3, LLC % % % BlackRock Cayman 1 LP % % % BlackRock Cayman West Bay Finco Limited % % % BlackRock Cayman West Bay IV Limited % % % BlackRock Group Limited % % % BlackRock Finance Europe Limited % % % BlackRock Advisors (UK) Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Holdco 3, LLC % % % BlackRock Cayman 1 LP % % % BlackRock Cayman West Bay Finco Limited % % % BlackRock Cayman West Bay IV Limited % % % BlackRock Group Limited % % % BlackRock Luxembourg Holdco S.a.r.l. % % % BlackRock (Luxembourg) S.A. % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Holdco 3, LLC % % % BlackRock Cayman 1 LP % % % BlackRock Cayman West Bay Finco Limited % % % BlackRock Cayman West Bay IV Limited % % % BlackRock Group Limited % % % BlackRock Finance Europe Limited % % % BlackRock Investment Management (UK) Limited % % % - % % % BlackRock, Inc. % % % BlackRock Saturn Subco, LLC % % % BlackRock Finance, Inc. % % % BlackRock Holdco 2, Inc. % % % BlackRock Financial Management, Inc. % % % BlackRock International Holdings, Inc. % % % BR Jersey International Holdings L.P. % % % BlackRock Holdco 3, LLC % % % BlackRock Cayman 1 LP % % % BlackRock Cayman West Bay Finco Limited % % % BlackRock Cayman West Bay IV Limited % % % BlackRock Group Limited % % % BlackRock Luxembourg Holdco S.a.r.l. % % % BlackRock UK Holdco Limited % % % BlackRock Asset Management Schweiz AG % % % - % % % 9. In case of proxy voting according to Sec. 34 para. 3 WpHG (only in case of attribution of voting rights in accordance with Sec. 34 para. 1 sent. 1 No. 6 WpHG) Date of general meeting: Holding total positions after general meeting (6.) after annual general meeting: Proportion of voting rights Proportion of instruments Total of both % % % 10. Other explanatory remarks: Date 06 Nov 2025 06.11.2025 CET/CEST The EQS Distribution Services include Regulatory Announcements, Financial/Corporate News and Press Releases. View original content: EQS News

Language:	English
Company:	Adtran Holdings, Inc.
	901 Explorer Boulevard
	35806 Huntsville
	United States
Internet:	www.adtran.com

End of News	EQS News Service

2225542  06.11.2025 CET/CEST