DEME Group NV

Transaction in Own Shares • Sep 3, 2025

PRESS RELEASE Regulated information September 3, 2025, 5:30 pm CET

SHARE BUYBACK PROGRAM COMPLETED

DEME Group NV announces that the share buyback program, which commenced on April 22, 2025, was completed on September 1, 2025.

The program involved the buyback of 40,000 shares for a total amount of 5,345,737 million euros. The average purchase price was 133.64 euros per share.

On September 1, 2025, the following transactions took place:

Repurchase of shares

Trade date	Number of shares	Average price (euro)	Highest price (euro)	Lowest price (euro)	Total amount (euro)	Market
01/09/2025	891	130.37	131.40	130.00	116,159.20	Euronext BXL (XBRU)

All details related to the acquisition of own shares by DEME Group NV can be found on www.deme-group.com.

About DEME

DEME (Euronext Brussels: DEME) is a leading contractor in the fields of offshore energy, environmental remediation, dredging, and marine infrastructure. DEME also engages in concessions activities in offshore wind, marine infrastructure, green hydrogen, and deep-sea mineral harvesting. The company can build on nearly 150 years of experience and is a front-runner in innovation and new technologies. DEME's vision is to work towards a sustainable future by offering solutions for global challenges: climate change, a growing population and urbanization, increasing maritime trade, and environmental issues. With a team of more than 5,800 highly skilled professionals and one of the most advanced fleets in the world, DEME is well-positioned to tackle even the most complex projects. DEME realized a turnover of 4.1 billion euros with an EBITDA of 764 million euros in 2024. For more information, please visit www.deme-group.com.

Contact

Media relations Investor relations Frederic Dryhoel Carl Vanden Bussche +32 473 86 31 91 +32 498 90 61 13

dryhoel.frederic@deme-group.com vanden.bussche.carl@deme-group.com