National Storage Mechanism | Additional information

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

OTHER RELEVANT INFORMATION

Reference is made to our notice of inside information of 30 July 2025 (official registry number 2844 ) (the "Buyback Commencement Communication"), relating to the buyback programme of own shares (the "Buyback Programme") approved by the Board of Directors of Banco Santander.

Pursuant to article 5 of Regulation (EU) no. 596/2014 on Market Abuse of 16 April 2014, and articles 2.2 and 2.3 of Commission Delegated Regulation (EU) 2016/1052, of 8 March 2016, the Bank informs of the transactions carried out over its own shares between 2 and 8 October 2025 (both inclusive).

The cash amount of the shares purchased to 8 October 2025 as a result of the execution of the Buyback Programme amounts to 603,268,044 Euros, which represents approximately 35.5% of the maximum investment amount of the Buyback Programme. The programme was announced together with its other characteristics through the Buyback Commencement Communication. With these purchases, the Bank has repurchased approximately 14.6% of its outstanding shares as of 2021.

Date	Security	Transaction	Trading venue	Number of shares	Weighted average price (€)
02/10/ 2025	SAN	Purchase	XMAD	1,652,572	8.7684
02/10/ 2025	SAN	Purchase	CEUX	103,730	8.7983
02/10/ 2025	SAN	Purchase	TQEX	21,792	8.8018
02/10/ 2025	SAN	Purchase	AQEU	21,906	8.8044
03/10/ 2025	SAN	Purchase	XMAD	1,062,295	8.7727
03/10/ 2025	SAN	Purchase	CEUX	95,764	8.7710
03/10/ 2025	SAN	Purchase	TQEX	20,346	8.7717
03/10/ 2025	SAN	Purchase	AQEU	21,595	8.7708
06/10/ 2025	SAN	Purchase	XMAD	1,255,767	8.7037
06/10/ 2025	SAN	Purchase	CEUX	69,710	8.7096
06/10/ 2025	SAN	Purchase	TQEX	38,194	8.7124
06/10/ 2025	SAN	Purchase	AQEU	36,329	8.7214
07/10/ 2025	SAN	Purchase	XMAD	1,535,134	8.6447
07/10/ 2025	SAN	Purchase	CEUX	96,482	8.6579
07/10/ 2025	SAN	Purchase	TQEX	22,104	8.6490
07/10/ 2025	SAN	Purchase	AQEU	46,280	8.6648
08/10/ 2025	SAN	Purchase	XMAD	1,437,486	8.7052
08/10/ 2025	SAN	Purchase	CEUX	96,666	8.7003
08/10/ 2025	SAN	Purchase	TQEX	24,895	8.6924
08/10/ 2025	SAN	Purchase	AQEU	40,953	8.7010
			TOTAL	7,700,000

Issuer name : Banco Santander, S.A. - LEI 5493006QMFDDMYWIAM13

Reference of the financial instrument : ordinary shares - Code ISIN ES0113900J37

Detailed information of the transactions carried out within the referred period is attached as Annex I.

Boadilla del Monte (Madrid), 9 October 2025

ANNEX I

Detailed information on each of the transactions carried out within the context of the Buy-back Programme between 02/10/2025 and 08/10/2025 (both inclusive)