Groupe Bruxelles Lambert SA

Transaction in Own Shares • Oct 20, 2025

Delivering meaningful growth

Transactions on GBL Shares

Disclosure of transaction on GBL shares from October 13, 2025, until October 17, 2025 (included) Implementation of the authorization of the Extraordinary General Shareholders' Meeting of April 28, 2020

Purchases

GBL, directly and through its subsidiaries, acquired during the period from October 13, 2025 until October 17, 2025 included, as part of:

• The share buyback program: 0 GBL share
• The share buyback program by an independent financial institution on the basis of a discretionary mandate (until November 7, 2025) in the central order book of a regulated market or MTF: 64,161 GBL shares

Trade date	Number of shares	Average price (EUR)	Lowest price (EUR)	Highest price (EUR)	Amount (EUR)	Market (MIC Code)
10/13/2025	6,900	77.68	77.40	77.95	536,002	CEUX
10/13/2025	1,508	77.87	77.60	78.00	117,424	TQEX
10/13/2025	16,661	77.62	77.40	78.00	1,293,273	XBRU
10/14/2025	3,427	77.20	77.10	77.30	264,572	CEUX
10/14/2025	1,740	77.33	77.10	77.60	134,555	TQEX
10/14/2025	5,018	77.26	76.95	77.60	387,667	XBRU
10/15/2025	2,305	77.55	77.20	77.70	178,759	CEUX
10/15/2025	988	77.66	77.50	77.80	76,723	TQEX
10/15/2025	9,109	77.55	77.25	77.85	706,401	XBRU
10/16/2025	3,549	77.83	77.40	78.15	276,218	CEUX
10/16/2025	1,674	77.69	77.30	78.15	130,056	TQEX
10/16/2025	5,530	77.76	77.50	78.20	430,027	XBRU
10/17/2025	1,954	76.62	76.35	76.95	149,714	CEUX
10/17/2025	227	76.45	76.45	76.45	17,354	TQEX
10/17/2025	3,571	76.72	76.45	77.30	273,968	XBRU
Total	64,161	77.50			4,972,713

• The liquidity agreement: 0 GBL share

Sales

GBL, directly and through its subsidiaries, sold during the period from October 13, 2025 until October 17, 2025 included, as part of:

• The liquidity agreement: 0 GBL share

As of October 17, 2025, GBL holds directly and through its subsidiaries 11,529,239 GBL shares representing 8.7% of the issued capital and holds no shares under the liquidity agreement. On that date, 13.0% of the eighth share buyback program is executed1.

Following GBL's decision to use the safe harbour2 regime for the on-the-market share buybacks in the context of a EUR 598.9 million envelope, the liquidity contract with an independent financial institution has been suspended for an indefinite period.

For more information, please contact:

Tel: +32 2 289 17 72 Tel: +32 2 289 17 64

Xavier Likin Alison Donohoe

Chief Financial Officer Head of Investor Relations xlikin@gbl.com adonohoe@gbl.com

About Groupe Bruxelles Lambert

Groupe Bruxelles Lambert ("GBL") is an established investment holding company, with seventy years of stock exchange listing and a net asset value of €14.4bn at the end of June 2025. As a leading and active investor in Europe, GBL focuses on long-term value creation with the support of a stable family shareholder base.

GBL is focused on delivering meaningful growth by providing attractive returns to its shareholders through a combination of growth in its net asset value per share, a sustainable dividend and share buybacks.

GBL is listed on Euronext Brussels (Ticker: GBLB BB; ISIN code: BE0003797140) and is included in the BEL20 index.

¹ cf. http://www.gbl.com/en/transactions-gbl-shares

² Provided for in Regulation (EU) No. 596/2014 of 16 April 2014 on market abuse and Delegated Regulation (EU) No. 2016/1052 of 8 March 2016 with regard to regulatory technical standards for the terms of buyback programs and stabilization measures