![\"\"\/](\"https:\/\/www.europesays.com\/spain\/wp-content\/uploads\/2026\/06\/1782388513_41_image_002.jpg\")
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FORM 6-K<\/p>\n
\u00a0<\/p>\n
SECURITIES AND EXCHANGE COMMISSION<\/p>\n
Washington, D.C. 20549<\/p>\n
\u00a0<\/p>\n
Report of Foreign Issuer<\/p>\n
\u00a0<\/p>\n
Pursuant to Rule 13a-16 or 15d-16 of\u00a0<\/p>\n
the Securities Exchange Act of 1934<\/p>\n
\u00a0<\/p>\n
For the month of June, 2026<\/p>\n
\u00a0<\/p>\n
Commission File Number: 001-12518<\/p>\n
\u00a0<\/p>\n
Banco Santander, S.A.\u00a0<\/p>\n
(Exact name of
\nregistrant as specified in its charter)<\/p>\n
\u00a0<\/p>\n
Ciudad Grupo Santander<\/p>\n
28660 Boadilla del Monte (Madrid) Spain<\/p>\n
(Address of principal
\nexecutive office)<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
Indicate by check mark whether the registrant
\nfiles or will file annual reports under cover of Form 20-F or Form 40-F:<\/p>\n
\u00a0<\/p>\n
\u00a0
\n Form 20-F
\n \u00a0X
\n \u00a0
\n Form 40-F
\n \u00a0
\n \u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
Banco Santander,
\nS.A.<\/p>\n
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TABLE OF CONTENTS<\/p>\n
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Item\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0
\n \u00a0<\/p>\n
1
\n Report of Other Relevant Information dated June 25, 2026<\/p>\n
\u00a0<\/p>\n
Item
\n1<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
Banco Santander, S.A. (the \u201cBank\u201d
\nor \u201cBanco Santander\u201d), in compliance with the Securities Market legislation, hereby communicates the following:<\/p>\n
\u00a0<\/p>\n
OTHER RELEVANT INFORMATION<\/p>\n
\u00a0<\/p>\n
Reference is made
\nto our notice of inside information of 4 February 2026 (official registry number 3077) (the \u201cBuyback Commencement Communication\u201d),
\nrelating to the buyback programme of own shares (the \u201cBuyback Programme\u201d) approved by the Board of Directors of Banco
\nSantander.<\/p>\n
\u00a0<\/p>\n
Pursuant to article 5 of Regulation (EU) no. 596\/2014
\non 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
\ninforms of the transactions carried out over its own shares between 18 and 24 June (both inclusive).<\/p>\n
\u00a0<\/p>\n
The cash amount of the shares purchased to 24 June
\n2026 as a result of the execution of the Buyback Programme amounts to 3,531,794,091 Euros, which represents approximately 70.2% of the
\nmaximum investment amount of the Buyback Programme. The programme was announced together with its other characteristics through the Buyback
\nCommencement Communication. With these purchases, the Bank has repurchased approximately 17.3% of its outstanding shares as of 2021.<\/p>\n
\u00a0<\/p>\n
Date
\n Security
\n Transaction
\n Trading venue
\n Number of shares<\/p>\n
Weighted average<\/p>\n
price (\u20ac)<\/p>\n
18\/06\/2026
\n SAN
\n Purchase
\n XMAD
\n 1,000,000
\n 11.8792<\/p>\n
19\/06\/2026
\n SAN
\n Purchase
\n XMAD
\n 4,000,000
\n 11.9306<\/p>\n
22\/06\/2026
\n SAN
\n Purchase
\n XMAD
\n 3,912,305
\n 11.9552<\/p>\n
23\/06\/2026
\n SAN
\n Purchase
\n XMAD
\n 3,095,432
\n 11.9281<\/p>\n
24\/06\/2026
\n SAN
\n Purchase
\n XMAD
\n 1,000,000
\n 11.9117<\/p>\n
\u00a0
\n \u00a0
\n \u00a0
\n TOTAL
\n 13,007,737
\n \u00a0<\/p>\n
\u00a0<\/p>\n
Issuer name: Banco Santander, S.A. – LEI
\n5493006QMFDDMYWIAM13<\/p>\n
\u00a0<\/p>\n
Reference of the financial instrument: ordinary
\nshares – Code ISIN ES0113900J37<\/p>\n
\u00a0<\/p>\n
Detailed information of the transactions carried
\nout within the referred period is attached as Annex I.<\/p>\n
\u00a0<\/p>\n
Boadilla del Monte (Madrid), 25 June 2026
\n<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
![\"\"\/](\"https:\/\/www.europesays.com\/spain\/wp-content\/uploads\/2026\/06\/1782388514_383_image_001.jpg\")
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\u00a0<\/p>\n
ANNEX I<\/p>\n
\u00a0<\/p>\n
Detailed information on each of the transactions
\ncarried out within the context of the Buy-back Programme between 18\/06\/2026 and 24\/06\/2026 (both inclusive)<\/p>\n
\u00a0<\/p>\n
(https:\/\/www.santander.com\/content\/dam\/santander-com\/es\/documentos\/cumplimiento\/do-anexo-i-18-a-24-junio-2026-es.pdf)<\/p>\n
\u00a0<\/p>\n
SIGNATURE<\/p>\n
\u00a0<\/p>\n
Pursuant to the
\nrequirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned,
\nthereunto duly authorized.<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n
\u00a0
\n Banco Santander, S.A.<\/p>\n
\u00a0
\n \u00a0<\/p>\n
\u00a0
\n \u00a0<\/p>\n
Date:
\n June 25, 2026
\n By:
\n \/s\/ Pedro de Mingo Kaminouchi<\/p>\n
\u00a0
\n \u00a0
\n \u00a0
\n Name:
\n Pedro de Mingo Kaminouchi<\/p>\n
\u00a0
\n \u00a0
\n \u00a0
\n Title:
\n Head of Corporate Compliance<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"\u00a0 \u00a0 \u00a0 \u00a0 FORM 6-K \u00a0 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 \u00a0 Report of Foreign…\n","protected":false},"author":2,"featured_media":12427,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[121],"tags":[20687,144,680,1431,20686,7458,1240,20688],"class_list":["post-45825","post","type-post","status-publish","format-standard","has-post-thumbnail","category-banco-santander","tag-6-k-report","tag-banco-santander","tag-capital-return","tag-european-bank","tag-own-shares","tag-san","tag-share-buyback","tag-xmad"],"_links":{"self":[{"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/posts\/45825","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/comments?post=45825"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/posts\/45825\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/media\/12427"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/media?parent=45825"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/categories?post=45825"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/spain\/wp-json\/wp\/v2\/tags?post=45825"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}