Groupe Bruxelles Lambert SA

Transaction in Own Shares • Dec 8, 2025

Delivering meaningful growth

Transactions on GBL Shares

Disclosure of transaction on GBL shares from December 1, 2025, until December 5, 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 1, 2025 until December 5, 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: 80,553 GBL shares

Trade date	Number of shares	Average price (EUR)	Lowest price (EUR)	Highest price (EUR)	Amount (EUR)	Market (MIC Code)
12/01/2025	1,035	74.41	74.15	74.90	77,014	AQEU
12/01/2025	10,867	74.49	74.00	75.25	809,492	CEUX
12/01/2025	1,480	74.38	74.10	75.05	110,088	TQEX
12/01/2025	5,426	74.66	74.00	75.30	405,079	XBRU
12/02/2025	1,059	74.22	73.90	74.50	78,597	AQEU
12/02/2025	5,413	74.21	73.95	74.60	401,715	CEUX
12/02/2025	1,436	74.21	73.95	74.60	106,564	TQEX
12/02/2025	2,466	74.22	73.80	74.60	183,021	XBRU
12/03/2025	1,261	73.67	73.40	73.95	92,900	AQEU
12/03/2025	5,812	73.63	73.40	74.05	427,946	CEUX
12/03/2025	1,500	73.66	73.40	73.90	110,490	TQEX
12/03/2025	5,052	73.53	73.40	73.90	371,492	XBRU
12/04/2025	1,300	73.92	73.60	74.15	96,095	AQEU
12/04/2025	7,613	73.97	73.50	74.15	563,145	CEUX
12/04/2025	1,500	73.89	73.50	74.15	110,831	TQEX
12/04/2025	9,781	73.92	73.50	74.20	723,009	XBRU
12/05/2025	1,287	74.52	74.10	74.75	95,905	AQEU
12/05/2025	4,386	74.59	74.10	74.75	327,131	CEUX
12/05/2025	1,500	74.51	74.10	74.70	111,760	TQEX
12/05/2025	10,379	74.29	73.90	74.80	771,007	XBRU
Total	80,553	74.15			5,973,279

• The liquidity agreement: 0 GBL share

Sales

GBL, directly and through its subsidiaries, sold during the period from December 1, 2025 until December 5, 2025 included, as part of:

• The liquidity agreement: 0 GBL share

As of December 5, 2025, GBL holds directly and through its subsidiaries 12,112,135 GBL shares representing 9.1% of the issued capital and holds no shares under the liquidity agreement. On that date, 21.7% 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