Endesa S.A.

Transaction in Own Shares • Oct 13, 2025

National Storage Mechanism | Additional information

Transaction in Own Shares

Borja Acha Besga

Secretary of the Board of Directors

Madrid, 13 October 2025

In accordance with the provisions of Article 227 of the Spanish Securities Market Act, Endesa, S.A. (hereinafter “Endesa” or “the Company”) discloses the following information in relation to the inside information communication dated 26 March 2025, registration number 2672, regarding the Share Buyback Framework Programme and in relation to the other relevant information dated 9 April 2025, registration number 34008:

• The Company reports that, it has resolved to bring forward the termination of the Second Tranche of the Share Buyback Framework Programme in accordance with the terms agreed with the financial institution through which said Second Tranche has been executed. The total number of shares purchased in the second tranche amounts to 17,007,566 shares at a weighted average price of 26,01 €/share. The foregoing represents an aggregate monetary amount of 442 million euros.

• The Company has approved the Third Tranche of the Share Buyback Programme for a maximum monetary amount of €500 million, with the purpose of reducing Endesa’s share capital through the cancellation of the treasury shares acquired (subject to the approval of the Company’s General Shareholders’ Meeting), and it will be carried out in accordance with the authorisation granted by the General Shareholders’ Meeting held on 24 April 2024 and the provisions of Regulation (EU) No 596/2014 of the European Parliament and of the Council of 16 April 2014 on market abuse, and Commission Delegated Regulation (EU) No 2016/1052 of 8 March 2016 (the “Third Tranche”).

Implementation of the Third Tranche is scheduled to begin in the coming days.

A corresponding announcement regarding the commencement and details of the Third Tranche (in accordance with Article 2 of Commission Delegated Regulation (EU) No 2016/1052) will be published in due course as a communication of other relevant information.

Secretary of the Board of Directors

Endesa, S.A. registered office in Madrid, C / Ribera del Loira, 60. Registered in the Madrid Commercial Registry, Sheet M-6405, volume 323, folio 1, TIN. A28023430

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Endesa, S.A.