桑坦德银行(US)美股招股说明书(2025-01-07版)

Filed Pursuant to Rule 424(b)(5)Registration Statement No. 333-271955 The information in this preliminary prospectus supplement is not complete and may be changed. This preliminaryprospectus supplement and the accompanying prospectus are not an offer to sell these securities nor do they seek anoffer to buy these securities in any jurisdiction where the offer or sale is not permitted. Subject to CompletionPreliminary Prospectus Supplement dated January 7, 2025 PRELIMINARY PROSPECTUS SUPPLEMENT(to prospectus dated May 16, 2023) $ Banco Santander, S.A. $% Senior Non Preferred Fixed Rate Notes due 2030 $% Senior Non Preferred Fixed Rate Notes due 2035 We are offering $principal amount of% Senior Non Preferred Fixed Rate Notes due 2030 (the“2030 Fixed Rate Notes”) and $principal amount of% Senior Non Preferred Fixed Rate Notesdue 2035 (the “2035 Fixed Rate Notes” and, together with the 2030 Fixed Rate Notes, the “Notes”). The 2030 Fixed Rate Notes will bear interest at a rate of% per year. From and including the date ofissuance, interest will be payable semi-annually in arrears on the 2030 Fixed Rate Notes on JanuaryandJulyof each year, beginning on July, 2025. The 2030 Fixed Rate Notes will be due on January, 2030. The 2035 Fixed Rate Notes will bear interest at a rate of% per year. From and including the date ofissuance, interest will be payable semi-annually in arrears on the 2035 Fixed Rate Notes on JanuaryandJulyof each year, beginning on July, 2025. The 2035 Fixed Rate Notes will be due on January, 2035. The Notes will be issued in minimum denominations of $200,000 and integral multiples of $200,000 in excessthereof. The payment obligations of Banco Santander, S.A. (“Banco Santander”) in respect of principal under the Notesconstitute direct, unconditional, unsubordinated and unsecured senior non preferred obligations (créditos ordinariosno preferentes) of Banco Santander and, in accordance with Additional Provision 14.2 of Law 11/2015 (as definedherein), but subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise),upon the insolvency of Banco Santander, such payment obligations rank (i)pari passuamong themselves and withany other Senior Non Preferred Liabilities (as defined herein), (ii) junior to the Senior Higher Priority Liabilities (asdefined herein) (and, accordingly, upon the insolvency of Banco Santander, the payment obligations of BancoSantander in respect of principal under the Notes will be met after payment in full of the Senior Higher Priority Liabilities) and (iii) senior to any present and future subordinated obligations (créditos subordinados) of BancoSantander in accordance with Article 281 of the Spanish Insolvency Law (as defined herein). By its acquisition of the Notes, each holder (which, for the purposes of this clause, includes each holder of abeneficial interest in the Notes) acknowledges, accepts, consents to and agrees to be bound by the terms of theNotes related to the exercise of the Bail-in Power (as defined herein) set forth under“Description of DebtSecurities—Agreement and Acknowledgement with Respect to the Exercise of the Bail-in Power” in theaccompanying prospectus. See“Notice to Investors”on page S-i of this prospectus supplement for furtherinformation. The Notes are not deposits or savings accounts and are not insured by the Federal Deposit Insurance Corporation orany other governmental agency of the Kingdom of Spain, the United States or any other jurisdiction. We may redeem the Notes of any series, in whole but not in part, at 100% of their principal amount plus accrued andunpaid interest (if any) (i) at any time upon the occurrence of certain tax events, (ii) at any time upon Table of Contents the occurrence of certain regulatory events set forth herein or (iii) if 75% or more of the initial aggregate principalamount of such series of Notes (which, for the avoidance of doubt, includes any additional issuances issuedsubsequently and constituting a single series of securities under the Base Indenture (as defined herein) as describedunder “Description of Debt Securities—Additional Issuances” in the accompanying prospectus) have been redeemedor purchased by, or on behalf of, Banco Santander and cancelled. We may not redeem the Notes of any series underother circumstances, and there are no put rights with respect to the Notes of any series. See “Description of theNotes—Redemption and Repurchase.” We intend to apply to list the Notes on the New York Stock Exchange in accordance with its rules. Investing in the Notes involves risks. See “Risk Factors” beginning on page S-13 of this prospectus supplement,page 7 of the accompanying prospectus as well as those discussed under the heading “Risk Factors” in theGroup’s Annual Report on Form 20-F for the year ended December 31, 2023 and under the heading “Part 2.Supplemental Information—Item 4. Risk Factors” in the Group’s Report on Form 6-K filed with the SEC onJul