Company: BCDRF
Filing Date: 2025-10-30
Form Type: 6-K
Source: 0000950103-25-013924
Chunk: 0

Company: Banco Santander, S.A.
Filing Date: 2025-10-30
Form: 6-K
Chunk 0
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<div align='center'>FORM 6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of October, 2025

Commission File Number: 001-12518

Banco Santander, S.A.

(Exact name of registrant as specified in its charter)

Ciudad Grupo Santander

28660 Boadilla del Monte (Madrid) Spain

(Address of principal executive office)</div>

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

| Form 20-F | X |     | Form 40-F |

<div align='center'>Banco Santander, S.A.

TABLE OF CONTENTS</div>

Item 1

Banco Santander, S.A.,(" Santander") communicates the following :

<div align='center'>OTHER RELEVANT INFORMATION</div>

Santander has been informed by the European Central Bank (“ ECB”), after following its Supervisory Review and Evaluation Process (“ SREP”), of its decision regarding the minimum prudential capital requirements effective as of 1 January 2026.

The ECB’s decision maintains an unchanged Pillar 2 requirement (“ P2R”) of 1.74% at a consolidated level, of which at least 0.98% must be covered with Common Equity Tier 1 capital (“ CET1”). 9 basis points of P2R reflect the capital add-on due to the ECB’s prudential expectations on calendar provisioning in connection with non-performing loans.

The following table shows the minimum CET1 and total capital requirements applicable at the consolidated level as of 1 January 2025 and as of 1 January 2026, as well as Santander's ratios 1as of 30 September 2025:

|               | Minimum       
 Requirement   |               | Data   |
| As            
 of 01/01/2025 | As            
 of 01/01/2026 | As            
 of 30/09/2025 |        |
| CET1          | 9.652%        | 9.85%3        | 13.09% |
| Total         
 Capital       | 13.912%       | 14.11%4       | 17.43% |

The