Groupe Bruxelles Lambert SA

Transaction in Own Shares • Dec 22, 2025

Delivering meaningful growth

Transactions on GBL Shares

Disclosure of transaction on GBL shares from December 15, 2025, until December 19, 2025 (included) Implementation of the authorization of the Extraordinary General Shareholders' Meeting of May 2, 2025

Purchases

GBL, directly and through its subsidiaries, acquired during the period from December 15, 2025 until December 19, 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 March 13, 2026) in the central order book of a regulated market or MTF: 76,108 GBL shares

Trade date	Number of shares	Average price (EUR)	Lowest price (EUR)	Highest price (EUR)	Amount (EUR)	Market (MIC Code)
12/15/2025	1,023	73.94	73.55	74.35	75,643	AQEU
12/15/2025	7,999	73.98	73.45	74.45	591,804	CEUX
12/15/2025	1,087	73.90	73.50	74.35	80,327	TQEX
12/15/2025	14,841	73.81	73.50	74.40	1,095,442	XBRU
12/16/2025	1,005	74.25	73.90	74.50	74,623	AQEU
12/16/2025	4,406	74.25	73.80	74.50	327,155	CEUX
12/16/2025	914	74.21	73.90	74.45	67,825	TQEX
12/16/2025	2,818	74.27	73.80	74.50	209,301	XBRU
12/17/2025	1,200	74.35	74.05	74.60	89,219	AQEU
12/17/2025	5,430	74.34	74.00	74.55	403,664	CEUX
12/17/2025	1,000	74.36	74.00	74.55	74,361	TQEX
12/17/2025	11,726	74.38	74.00	74.55	872,185	XBRU
12/18/2025	1,146	74.70	74.60	74.85	85,608	AQEU
12/18/2025	5,557	74.73	74.55	74.95	415,281	CEUX
12/18/2025	1,000	74.73	74.55	74.90	74,726	TQEX
12/18/2025	3,095	74.76	74.55	74.95	231,373	XBRU
12/19/2025	1,084	74.82	74.65	75.00	81,110	AQEU
12/19/2025	5,761	74.84	74.65	75.05	431,156	CEUX
12/19/2025	900	74.83	74.65	75.00	67,346	TQEX
12/19/2025	4,116	74.89	74.65	75.05	308,231	XBRU
Total	76,108	74.32			5,656,380

• The liquidity agreement: 0 GBL share

Sales

GBL, directly and through its subsidiaries, sold during the period from December 15, 2025 until December 19, 2025 included, as part of:

• The liquidity agreement: 0 GBL share

As of December 19, 2025, GBL holds directly and through its subsidiaries 12,287,894 GBL shares representing 9.2% of the issued capital and holds no shares under the liquidity agreement. On that date, 24.3% 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 €14.0bn at the end of September 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