Company: BCDRF
Filing Date: 2025-07-01
Form Type: 6-K
Source: 0000950103-25-008240
Chunk: 0

Company: Banco Santander, S.A.
Filing Date: 2025-07-01
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 July, 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

<div align='center'>Santander to acquire TSB from Sabadell

for £2.65 billion</div>

| · | The                                                                                 
 all-cash transaction values TSB at 5x 2026 earnings1 post identified cost synergies 
 and 1.45x tangible book value as of 31 March 20252.                                 |

| · | The acquisition would strengthen Santander’s                                                                                          
 position in the UK. Santander intends to integrate TSB in the Santander UK group, enabling it to become the third largest bank in the 
 country by personal current account balances.                                                                                         |

| · | The transaction is expected to generate a return                                                                                  
 on invested capital of over 20%, thereby contributing to an increase in Santander UK’s return on tangible equity from 11% in 2024 
 to 16% in 2028, in line with leading UK peers, with cost synergies of at least £400 million or 13% of the combined business’s     
 cost base.                                                                                                                        |

| · | The acquisition is expected to result in earnings                                                                                     
 per share accretion for Santander from the first year and of c.4% in 2028 while consuming 50 basis points of CET1 capital at closing. 
 The transaction is consistent with Santander’s strategy to carry out bolt-on acquisitions to accelerate organic growth in its core    
 markets while adhering to Santander’s strict capital hierarchy.                                                                       |

| · | The                                                                                     
 transaction will not affect Santander’s distribution policy and 202