Report 11/2026 - Submission by the Company of a Request for Arbitration Against GE Hydro France S.A.S.

In reference to current report No. 22/2025 dated December 19, 2025, the Management Board of Mostostal Warszawa S.A. (the "Company") informs that on April 3, 2026, the Company filed a request for arbitration against GE Hydro France S.A.S. (the "Respondent") with the International Court of Arbitration of the International Chamber of Commerce ("ICC").

The request for arbitration concerns the Company's claims against the Respondent arising in connection with the Consortium Agreement dated April 21, 2022 (the "Consortium Agreement") under which the Company acted as a partner, while the Respondent acted as the leader of the Consortium, in the implementation of contract No. CRU/340/OP/2022 regarding the modernization of the technological part of the Porąbka-Żar hydroelectric power plant for PGE Energia Odnawialna S.A. (the "Contracting Authority") (the "Project Agreement"), as the Company reported in Current Reports No. 12/2022 dated July 22, 2022, and No. 1/2025 dated January 13, 2025.

The Company estimates the current value of claims covered by the request for arbitration at USD 35 million. This amount may change in the course of further arbitration proceedings. The Company's claims aim to establish that the Respondent is liable for breaches of the Consortium Agreement, to obtain compensation for damages resulting from these breaches, and to secure the Company against potential claims from third parties, including the Contracting Authority, in relation to the statement of withdrawal from the Project Agreement.

In the Management Board's opinion, due to its significant value, the above event may have a potentially significant impact on the future financial results of the Company, including the financial statement for the year 2025, which is currently being audited by a certified auditor and will be assessed by an auditor and approved by the competent authorities of the Company.