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, 2026
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)
Indicate by check mark whether the registrant
files or will file annual reports under cover of Form 20-F or Form 40-F:
Banco Santander,
S.A.
TABLE OF CONTENTS
Item
1
Report of Other Relevant Information dated July 9, 2026
Item 1
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 4 February 2026 (official registry number 3077) (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 July (both inclusive).
The cash amount of the shares purchased to 8 July 2026 as a result of
the execution of the Buyback Programme amounts to 3,756,788,259 Euros, which represents approximately 74.7% 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 17.4% of its outstanding shares as of 2021.
Date
Security
Transaction
Trading venue
Number of shares
Weighted average price (€)
02/07/2026
SAN
Purchase
XMAD
1,319,652
12.2656
03/07/2026
SAN
Purchase
XMAD
2,000,000
12.4069
06/07/2026
SAN
Purchase
XMAD
1,855,755
12.4454
07/07/2026
SAN
Purchase
XMAD
2,000,000
12.5256
08/07/2026
SAN
Purchase
XMAD
3,000,000
11.9252
TOTAL
10,175,407
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 July 2026
ANNEX I
Detailed
information on each of the transactions carried out within the context of the Buy-back Programme between 02/07/2026 and 08/07/2026 (both
inclusive)
(https://www.santander.com/content/dam/santander-com/es/documentos/cumplimiento/do-anexo-i-02-a-08-julio-2026-es.pdf)
SIGNATURE
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.
Banco Santander, S.A.
Date:
July 9, 2026
By:
/s/ Pedro de Mingo Kaminouchi
Name:
Pedro de Mingo Kaminouchi
Title:
Head of Corporate Compliance