桑坦德银行美股招股说明书(2026-04-09版)

$3,650,000,000 Banco Santander, S.A. $400,000,000 Senior Non Preferred Floating Rate Notes due 2029 $1,000,000,000 4.600% Senior Non Preferred Fixed Rate Notes due 2029$1,250,000,000 4.867% Senior Non Preferred Fixed Rate Notes due 2031$1,000,000,000 5.437% Senior Non Preferred Fixed Rate Notes due 2036 We are offering $400,000,000 principal amount of Senior Non Preferred Floating Rate Notes due 2029 (the “2029 Floating Rate Notes”),$1,000,000,000 principal amount of 4.600% Senior Non Preferred Fixed Rate Notes due 2029 (the “2029 Fixed Rate Notes”), $1,250,000,000 principalamount of 4.867% Senior Non Preferred Fixed Rate Notes due 2031 (the “2031 Fixed Rate Notes”), and $1,000,000,000 principal amount of 5.437%Senior Non Preferred Fixed Rate Notes due 2036 (the “2036 Fixed Rate Notes” and, together with the 2029 Floating Rate Notes, the 2029 Fixed RateNotes and the 2031 Fixed Rate Notes, the “Notes”). The 2029 Floating Rate Notes will bear interest at the 2029 Floating Rate Interest Rate (as defined herein). From and including the date ofissuance, interest will be payable quarterly in arrears on the 2029 Floating Rate Notes on January15, April15, July15 and October15 of each year,beginning on July15, 2026. Unless we redeem the 2029 Floating Rate Notes earlier, the 2029 Floating Rate Notes will be due on April15, 2029. The 2029 Fixed Rate Notes will bear interest at a rate of 4.600% per year. From and including the date of issuance, interest will be payable semi-annually in arrears on the 2029 Fixed Rate Notes on April15 and October15 of each year, beginning on October15, 2026. Unless we redeem the 2029Fixed Rate Notes earlier, the 2029 Fixed Rate Notes will be due on April15, 2029. The 2031 Fixed Rate Notes will bear interest at a rate of 4.867% per year. From and including the date of issuance, interest will be payable semi-annually in arrears on the 2031 Fixed Rate Notes on April15 and October15 of each year, beginning on October15, 2026. Unless we redeem the 2031Fixed Rate Notes earlier, the 2031 Fixed Rate Notes will be due on April15, 2031. The 2036 Fixed Rate Notes will bear interest at a rate of 5.437% per year. From and including the date of issuance, interest will be payable semi-annually in arrears on the 2036 Fixed Rate Notes on April15 and October15 of each year, beginning on October15, 2026. Unless we redeem the 2036Fixed Rate Notes earlier, the 2036 Fixed Rate Notes will be due on April15, 2036. 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 Banco Santander and, in accordance withAdditional Provision 14.2 of Law 11/2015 (as defined herein) (but subject to any other ranking that may apply as a result of any mandatory provision oflaw (or otherwise)), upon the insolvency of Banco Santander, such payment obligations rank (i)pari passuamong themselves and with any other SeniorNon Preferred Liabilities (as defined herein), (ii) junior to the Senior Higher Priority Liabilities (as defined herein) (and, accordingly, upon theinsolvency of Banco Santander, Table of Contents the payment obligations 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 in accordance withArticle281 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 a beneficial interest in theNotes) acknowledges, accepts, consents to and agrees to be bound by the terms of the Notes related to the exercise of the Bail-in Power (asdefined herein) set forth under“Description of Debt Securities—Agreement and Acknowledgement with Respect to the Exercise of the Bail-inPower” in the accompanying prospectus. See“Notice to Investors”on page S-i of this prospectus supplement for further information. 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. Subject to the terms and conditions under “Description of the Notes—Redemption and Repurchase,” we may redeem the Notes of any series, inwhole but not in part, at 100% of their principal amount plus accrued and unpaid interest (if any), (i) at any time upon the occurrence of a Tax Event (asdefined herein), (ii) at any time upon the occurrence of a TLAC/MREL Disqualification Event (as defined herein) or (iii)if 75% or more of the initialaggregate principal amount of such series of Notes have been redeemed or purchased by, or on