Banco Santander, S.A. (the "Issuer" or the "Bank"), in compliance with the Securities Market legislation, hereby communicates the following:

OTHER RELEVANT INFORMATION

In relation to the "Issuance of Banco Santander, S.A. Internationalization Covered Bonds Series 4 - March 2026" ("Emisión de Cédulas de Internacionalización Banco Santander, S.A. Serie 4 - Marzo 2026"), with ISIN code ES0413900707, for an amount of one billion dolars (USD 1,000,000,000), whose Final Conditions were filed with the Spanish National Securities Market Commission (the "CNMV") on 4 March 2021 (hereinafter, as amended on the 3^rd May 2023, the "Issuance" or the "Series 4")", the Issuer has carried out a process to gather the consent of each and every investor of the Issuance for the purpose of: (i) extending the maturity of the Issuance, and accordingly, (ii) modifying the applicable interest rate which should be applicable from the next interest payment date (excluded) to the new maturity date (included).

In particular, once the consent of the holders representing 100% of the Issuance has been obtained, the following modifications have been made:

-     the maturity date (previously being 4^th March 2026) is extended up to the 4^th September 2030; and

-     the interest rate (previously being Compounded SOFR 6 months plus 53.826 basis points) applicable from the next interest payment date (excluded), i.e., 4^th September 2025, to the new maturity date is: Compounded SOFR 6 months plus 55.942 basis points (as defined in the Final Conditions attached as Annex I).

In everything not expressly described in the preceding paragraphs, the same terms and conditions that were established in the Final Conditions, prior to this modification, will still apply.

New Final Conditions applicable to Series 4 are attached to this notice as Annex I.

Likewise, it is hereby stated that all the necessary communications have been made to the relevant bodies.

The foregoing is hereby disclosed as other relevant information for all relevant purposes.

Boadilla del Monte (Madrid), 29 August 2025

ANNEX I

IMPORTANT INFORMATION

Not a securities offer

This document and the information it contains does not constitute an offer to sell nor the solicitation of an offer to buy any securities.