桑坦德银行美股招股说明书(2025-10-30版)

$ Banco Santander, S.A. $Senior Non Preferred Floating Rate Notes due 2030$% 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 Floating Rate Notes due 2030 (the “2030 Floating RateNotes”), $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 Notes due 2035 (the “2035 Fixed Rate Notes” and,together with the 2030 Floating Rate Notes and the 2030 Fixed Rate Notes, the “Notes”). The 2030 Floating Rate Notes will bear interest at the 2030 Floating Rate Interest Rate (as defined herein). From and includingthe date of issuance, interest will be payable quarterly in arrears on the 2030 Floating Rate Notes on February, May,Augustand Novemberof each year, beginning on February, 2026. Unless we redeem the 2030 Floating Rate Notesearlier, the 2030 Floating Rate Notes will be due on November, 2030. The 2030 Fixed Rate Notes will bear interest at a rate of% per year. From and including the date of issuance, interest willbe payable semi-annually in arrears on the 2030 Fixed Rate Notes on Mayand Novemberof each year, beginningon May, 2026. Unless we redeem the 2030 Fixed Rate Notes earlier, the 2030 Fixed Rate Notes will be due on November,2030. The 2035 Fixed Rate Notes will bear interest at a rate of% per year. From and including the date of issuance, interest willbe payable semi-annually in arrears on the 2035 Fixed Rate Notes on Mayand Novemberof each year, beginning on May, 2026. Unless we redeem the 2035 Fixed Rate Notes earlier, the 2035 Fixed Rate Notes will be due on November, 2035. The Notes will be issued in minimum denominations of $200,000 and integral multiples of $200,000 in excess thereof. The payment obligations of Banco Santander, S.A. (“Banco Santander”) in respect of principal under the Notes constitute direct,unconditional, unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of BancoSantander and, in accordance with Additional Provision 14.2 of Law 11/2015 (as defined herein), but subject to any other ranking thatmay apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander, such paymentobligations rank (i)pari passuamong themselves and with any other Senior Non Preferred Liabilities (as defined herein), (ii) juniorto the Senior Higher Priority Liabilities (as defined herein) (and, accordingly, upon the insolvency of Banco Santander, the paymentobligations of Banco Santander in respect of principal under the Notes will be met after payment in full of the Senior Higher PriorityLiabilities) and (iii)senior to any present and future subordinated obligations (créditos subordinados) of Banco Santander inaccordance with Article 281 of the Spanish Insolvency Law (as defined herein). The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectussupplement and the accompanying prospectus are not an offer to sell these securities nor do they seek an offer to buy these securitiesin any jurisdiction where the offer or sale is not permitted.By its acquisition of the Notes, each holder (which, for the purposes of this clause, includes each holder of a beneficialinterest in the Notes) acknowledges, accepts, consents to and agrees to be bound by the terms of the Notes related to theexercise of theBail-inPower (as defined herein) set forth under“Description of Debt Securities—Agreement andAcknowledgement with Respect to the Exercise of theBail-inPower” in the accompanying prospectus. See“Notice to Investors”on pageS-iof this prospectus supplement for further information. Table of Contents The Notes are not deposits or savings accounts and are not insured by the Federal Deposit Insurance Corporation or any other governmentalagency 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 and unpaid interest (if any)(i) atany time upon the occurrence of certain tax events, (ii)at any time upon the occurrence of certain regulatory events set forth herein or (iii)if 75% ormore of the initial aggregate principal amount 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 described under “Description of DebtSecurities—Additional Issuances” in the accompanying prospectus) have been redeemed or purchased by, or on behalf of, Banco Santander andcancelled. We may not redeem the Notes of any series under other circumstances, and there are no put rights with respect to the Notes of any series. See“Description of the Notes—Redemption and Repurchase.” We intend to apply to list the Notes on