Company: BCDRF
Filing Date: 2025-12-11
Form Type: 6-K
Source: 0000950103-25-015982
Chunk: 1

Company: Banco Santander, S.A.
Filing Date: 2025-12-11
Form: 6-K
Chunk 1
---
    35,951 |            9.5119 |
| 10/12/2025 | SAN      | Purchase    | XMAD    | 1,839,866 |            9.5493 |
| 10/12/2025 | SAN      | Purchase    | CEUX    |   117,976 |            9.5517 |
| 10/12/2025 | SAN      | Purchase    | TQEX    |    42,158 |            9.5515 |
|            |          |             | TOTAL   | 7,100,000 |                   |

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), 11 December 2025

1

<div align='center'>ANNEX I</div>

Detailed information on each of the transactions carried out within the context of the Buy-back Programme between 04/12/2025 and 10/12/2025 (both inclusive)

(https://www.santander.com/content/dam/santander-com/es/documentos/cumplimiento/do-anexo-i-04-a-10-12-2025.pdf)

2

<div align='center'>SIGNATURE</div>

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

| Date: | December 11, 2025 |     | Banco Santander, S.A. 
 By:                   | /s/ Pedro de Mingo Kaminouchi |                              |
|:------|:------------------|:----|:----------------------|:------------------------------|:-----------------------------|
|       |                   |     |                       | Name:                         | Pedro de Mingo Kaminouchi    |
|       |                   |     |                       | Title:                        | Head of Corporate Compliance |