FORTUM CORPORATION STOCK EXCHANGE RELEASE 30 SEPTEMBER 2025 AT 14.30 Release category: Other information disclosed according to the rules of the Exchange Fortum's Board of Directors has decided to launch the savings period for the year 2026 under its Employee Share Savings (ESS) programme. The ESS programme was established in October 2019 and the Board of Directors decides separately on the annual launch of each individual savings period. The objective of the ESS programme is to motivate Fortum employees to invest in Fortum shares and retain ownership in the company and to align the employees' interests with its shareholders. The participants of the ESS programme will invest a part of their monthly salary and based on this investment will, as a gross reward, be granted one matching share for each two purchased savings shares after approximately three years from the beginning of the savings period. The prerequisites for receiving matching shares are that a participant holds the purchased savings shares until the end of the holding period, and that their employment has not ended before the end of the holding period. The holding period for the 2026 savings period will end on 28 February 2029. The terms and conditions of the savings programme are the same as in previous programmes. The ESS programme is available to employees of the Fortum Group, with the exception of employees in countries where local legislation or other reasons make it unfeasible. The total amount of all savings for the 2026 savings period may not exceed EUR 7 million. Fortum Corporation Ingela Ulfves Vice President, Investor Relations and Financial Communications Further information: Jari Laitinen, Vice President, Performance and Rewards, tel. +358 40 660 2506 Investors and analysts: Ingela Ulfves, Vice President, Investor Relations and Financial Communications, tel. +358 40 515 1531 Rauno Tiihonen, Director, Investor Relations, tel. +358 10 453 6150 Siri Markula, Director, Investor Relations and Financial Communications, tel. +358 40 743 2177 Media: Fortum News Desk, tel. +358 40 198 2843 Distribution: Nasdaq Helsinki Main media www.fortum.com Fortum Fortum is a Nordic energy company. We generate and deliver reliable energy to our customers and the Nordic energy system while at the same time helping industries decarbonise their processes and grow. Our core operations comprise efficient and best-in-class low-carbon power generation, customer services, and heating and cooling. Fortum's power generation is already 99% from renewable or nuclear sources with one of the lowest specific CO2-emissions in Europe. We are guided by our ambitious SBTi-validated emission reduction targets on our way towards net-zero by 2040. For our ~4,500 employees, we commit to be a safe and inspiring workplace. Fortum's share is listed on Nasdaq Helsinki. fortum.com (https://www.fortum.com)