National Storage Mechanism | Additional information

Vianet Group PLC

(the "Company")

TR-1: Notification of Major Holdings

Vianet Group plc (AIM: VNET), a leader in delivering actionable data and business insights through an integrated ecosystem of hardware devices, software platforms, and smart insights portals, is pleased to confirm that the company has received notification that Lord Lee of Trafford crossed a threshold regarding major holdings. The notification, pertaining to an acquisition of voting rights, indicates that Lord Lee's total voting rights attached to shares in the Company is 3.80% as of October 27, 2025.

Enquiries:

Vianet Group PLC
James Dickson, Chairman & CEO Sarah Bentham, CFO	Tel: +44 (0) 1642 358 800 www.vianetplc.com
Cavendish Capital Markets Limited
Stephen Keys / Isaac Hooper	Tel: +44 (0) 20 7220 0500

Investor Enquiries:
Dale Bellis	Tel: +44 (0) 20 7397 1928
	www.cavendish.com

NOTIFICATION OF MAJOR HOLDINGS (to be sent to the relevant issuer and to the FCA in Microsoft Word format if possible) ⁱ

1a. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached ⁱⁱ :			Vianet Group Plc
1b. Please indicate if the issuer is a non-UK issuer (please mark with an "X" if appropriate)
Non-UK issuer
2. Reason for the notification (please mark the appropriate box or boxes with an "X")
An acquisition or disposal of voting rights						X
An acquisition or disposal of financial instruments
An event changing the breakdown of voting rights
Other (please specify)ⁱⁱⁱ: Placing of shares
3. Details of person subject to the notification obligation ^iv
Name			Lord Lee of Trafford
City and country of registered office (if applicable)			London, United Kingdom
4. Full name of shareholder(s) (if different from 3) ^v
Name
City and country of registered office (if applicable)
5. Date on which the threshold was crossed or reached ^vi :			27 October 2025
6. Date on which issuer notified (DD/MM/YYYY):			27/10/2025
7. Total positions of person(s) subject to the notification obligation
	% of voting rights attached to shares (total of 8. A)	% of voting rights through financial instruments (total of 8.B 1 + 8.B 2)		Total of both in % (8.A + 8.B)	Total number of voting rights of issuer ^vii
Resulting situation on the date on which threshold was crossed or reached	3.80%			3.80%	1,081,000
Position of previous notification (if applicable)	N/A			N/A

8. Notified details of the resulting situation on the date on which the threshold was crossed or reached ^viii
A: Voting rights attached to shares
Class/type of shares ISIN code (if possible)		Number of voting rights ^ix					% of voting rights
		Direct (Art 9 of Directive 2004/109/EC) (DTR5.1)		Indirect (Art 10 of Directive 2004/109/EC) (DTR5.2.1)			Direct (Art 9 of Directive 2004/109/EC) (DTR5.1)		Indirect (Art 10 of Directive 2004/109/EC) (DTR5.2.1)
Ordinary GB00B13YVN56		1,081,000					3.80%


SUBTOTAL 8. A		1,081,000					3.80%

B 1: Financial Instruments according to Art. 13(1)(a) of Directive 2004/109/EC (DTR5.3.1.1 (a))
Type of financial instrument		Expiration date ^x	Exercise/ Conversion Period ^xi			Number of voting rights that may be acquired if the instrument is exercised/converted.			% of voting rights



			SUBTOTAL 8. B 1

B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC (DTR5.3.1.1 (b))
Type of financial instrument	Expiration date ^x		Exercise/ Conversion Period ^xi		Physical or cash settlement ^xii			Number of voting rights	% of voting rights



					SUBTOTAL 8.B.2

9. Information in relation to the person subject to the notification obligation (please mark the applicable box with an "X")
Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuer ^xiii
Full chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held starting with the ultimate controlling natural person or legal entity ^xiv (please add additional rows as necessary)				X
Name ^xv	% of voting rights if it equals or is higher than the notifiable threshold	% of voting rights through financial instruments if it equals or is higher than the notifiable threshold	Total of both if it equals or is higher than the notifiable threshold
Lord Lee of Trafford	3.80%		3.80%


10. In case of proxy voting, please identify:
Name of the proxy holder		NA
The number and % of voting rights held		NA
The date until which the voting rights will be held		NA

11. Additional information ^xvi

Place of completion	London, United Kingdom
Date of completion	27 October 2025