Adtran Holdings, Inc. UBS Group AG, Zurich, Switzerland

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
14.08.2026 / 15:24 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
	Other reason:

3. Details of person subject to the notification obligation

Legal entity: UBS Group AG
City of registered office, country: Zurich, Switzerland

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:

12 Aug 2026

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	1.12 %	3.75 %	4.88 %	81481407
Previous notification	1.72 %	3.66 %	5.37 %	/

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	915997	0 %	1.12 %
Total	915997		1.12 %

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 %
Rights of Use over Shares		At any time	107985	0.13 %
Right to Recall of Lent shares		At any time	1229454	1.51 %
Right of Use over Long Call Options	21/08/2026	At any time	2200	0 %
		Total	1339639	1.64 %

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 %
Equity Swaps	11/11/2027 – 31/05/2028		Cash	304	0 %
Convertible Notes (US00486HAA32)	15/09/2030	19/09/2025 – 14/09/2030	Physical	1717572	2.11 %
			Total	1717876	2.11 %

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)
UBS Group AG	%	%	%
UBS AG	%	%	%
UBS Americas Holding LLC	%	%	%
UBS Americas Inc.	%	%	%
UBS Asset Management (Americas) LLC	%	%	%
–	%	%	%
UBS Group AG	%	%	%
UBS AG	%	%	%
UBS Asset Management AG	%	%	%
UBS Asset Management (Europe) S.A.	%	%	%
–	%	%	%
UBS Group AG	%	%	%
UBS AG	%	%	%
UBS Americas Holding LLC	%	%	%
UBS Americas Inc.	%	%	%
UBS Financial Services Inc.	%	%	%
–	%	%	%
UBS Group AG	%	%	%
UBS AG	%	%	%
UBS Asset Management AG	%	%	%
UBS Asset Management Switzerland AG	%	%	%
UBS Fund Management (Switzerland) AG	%	%	%
–	%	%	%
UBS Group AG	%	%	%
UBS AG	%	%	%
UBS Americas Holding LLC	%	%	%
UBS Americas Inc.	%	%	%
UBS Securities LLC	%	%	%
–	%	%	%
UBS Group AG	%	%	%
UBS AG	%	%	%
UBS Switzerland 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

14 Aug 2026

14.08.2026 CET/CEST The EQS Distribution Services include Regulatory Announcements, Financial/Corporate News and Press Releases.

Language:	English
Company:	Adtran Holdings, Inc.
	901 Explorer Boulevard
	35806 Huntsville
	United States
Internet:	www.adtran.com
LEI Code:	549300VV36J86CRRWF77


End of News	EQS News Service

2383368 14.08.2026 CET/CEST