Company: BCDRF
Filing Date: 2025-12-04
Form Type: 6-K
Source: 0000950103-25-015715
Chunk: 1

Company: Banco Santander, S.A.
Filing Date: 2025-12-04
Form: 6-K
Chunk 1
---
5 | SAN      | Purchase    | AQEU          |           52,716 |                     9.4309 |
| 03/12/2025 | SAN      | Purchase    | XMAD          |        1,855,974 |                     9.4422 |
| 03/12/2025 | SAN      | Purchase    | CEUX          |          128,122 |                     9.4530 |
| 03/12/2025 | SAN      | Purchase    | TQEX          |           38,918 |                     9.4405 |
| 03/12/2025 | SAN      | Purchase    | AQEU          |           76,986 |                     9.4527 |
|            |          |             | TOTAL         |        9,600,000 |                            |

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), 4 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 27/11/2025 and 03/12/2025 (both
inclusive)

(https://www.santander.com/content/dam/santander-com/es/documentos/cumplimiento/do-anexo-i-27-11-a-03-12-2025.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 4, 2025 | Banco Santander, S.A. 
 By:                   | /s/ Pedro de Mingo Kaminouchi |                              |
|:------|:-----------------|:----------------------|:------------------------------|:-----------------------------|
|       |                  |                       | Name:                         | Pedro de Mingo Kaminouchi    |
|       |                  |                       | Title:                        | Head of Corporate Compliance |