Santander Holdings USA, Inc.

EX-1.1 · d297610dex11.htm

EX-1.1
 2
 d297610dex11.htm
 EX-1.1

 Exhibit 1.1

 [Execution Version]

 Santander Holdings USA, Inc.

 $1,000,000,000 5.040% Fixed-to-Floating Rate Senior Notes due
2030
 $750,000,000 5.220% Fixed-to-Floating Rate
Senior Notes due 2032
 $750,000,000 5.701%
 Fixed-to-Floating Rate Senior Notes due 2037

 Underwriting Agreement

 June 2, 2026
 Santander US Capital Markets
LLC
 BofA Securities, Inc.
 Citigroup Global Markets Inc.

 J.P. Morgan Securities LLC
 Morgan Stanley & Co.
LLC
 RBC Capital Markets, LLC
 c/o Santander US Capital
Markets LLC
 437 Madison Avenue
 New York, New York 10022

 c/o BofA Securities, Inc.
 711 5th Avenue

 New York, New York 10022
 c/o Citigroup Global Markets Inc.

 388 Greenwich Street
 New York, New York 10013

 c/o J.P. Morgan Securities LLC
 270 Park Avenue

 New York, New York 10017
 c/o Morgan Stanley & Co. LLC

 1585 Broadway
 New York, New York 10036

 c/o RBC Capital Markets, LLC
 Brookfield Place

 200 Vesey Street, 8th Floor
 New York, New York 10281

 As Representatives of the several Underwriters listed in Schedule I hereto

 To the addressees set forth above:
 Santander Holdings USA,
Inc., a Virginia corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to issue and sell to the several underwriters listed in Schedule I hereto (each an “Underwriter” and collectively, the
“Underwriters”), for whom Santander US Capital Markets LLC (“SanCap”), BofA Securities, Inc., Citigroup Global Markets Inc., J.P. Morgan Securities LLC, Morgan Stanley & Co. LLC and RBC Capital Markets, LLC are
acting as Representatives (the “Representatives” or “you”), as set forth in Schedule I hereto an aggregate of (i) $1,000,000,000 principal amount of the 5.040%
 Fixed-to-Floating Rate Senior Notes due 2030 (the “2030 Notes”), (ii) $750,000,000 principal amount of the 5.220% Fixed-to-Floating Rate Senior Notes due 2032 (the “2032 Notes”) and (iii) $750,000,000 principal amount of the 5.701%
 Fixed-to-Floating Rate Senior Notes due 2037 of the Company (the “2037 Notes” and, together with the 2030 and 2032 Notes, the “Securities”). The
Securities will be issued pursuant to the Senior Debt Indenture, dated as of April 19, 2011, between the Company and Deutsche Bank Trust Company, the trustee (the “Trustee”), as amended and supplemented by the Eighth Supplemental
Indenture, dated as of March 1, 2017, between the Company and the Trustee, and as supplemented by one or more supplemental indentures to be entered into between the Company and the Trustee (together, the “Indenture”).

 As previously announced, on February 3, 2026, Banco Santander, S.A., a Spanish sociedad anónima (“Banco Santander”), which owns all of
the outstanding shares of capital stock of the Company (together with Banco Santander and its affiliates, “Santander”), entered into a Transaction Agreement (the “Transaction Agreement”) with Webster Financial Corporation, a
Delaware corporation (“Webster”), which owns all of the outstanding shares of capital stock of Webster Bank, National Association (“WBNA”), and a wholly-owned subsidiary of Webster incorporated in the State of Virginia
(“Webster Virginia”). Among other things, the Transaction Agreement provides for the merger of Webster with and into Webster Virginia, with Webster Virginia continuing, as the surviving corporation in such merger transaction, and,
immediately afterwards, the acquisition by Banco Santander of all outstanding shares of Webster Virginia common stock through a statutory share exchange, all subject to the terms and conditions of the Transaction Agreement (collectively, the
“HoldCo Transactions”). Following the completion of the HoldCo Transactions, Banco Santander intends to contribute all outstanding shares of Webster Virginia common stock to the Company (the “Webster Virginia Contribution”).
Additionally, following the completion of the Webster Virginia Contribution, Banco Santander intends, but is not required pursuant to the terms of the Transaction Agreement, (i) to merge Webster Virginia with and into the Company, with the
Company continuing as the surviving corporation in such merger; and (ii) to merge WBNA with and into the Bank, with the Bank being the surviving bank of such merger.

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 1. The Company represents and warrants to, and agrees with, each of the Underwriters that:

 (a) A registration statement on Form S-3 (File No. 333-276089), (the “Initial Registration Statement”) in respect of the Securities has been filed with the Securities and Exchange Commission (the “Commission”); the Initial
Registration Statement and any post-effective amendment thereto, each in the form heretofore delivered to you, excluding exhibits to the Initial Registration Statement, but including all documents incorporated
by reference in the prospectus included therein, have become or been declared effective by the Commission in such form; other than a registration statement, if any, increasing the size of the offering (a “Rule 462(b) Registration
Statement”), filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the “Act”), which became effective upon filing, no other document with respect to the Initial Registration Statement or document incorporated
by reference therein, but excluding any Statement of Eligibility (Form T-1) under the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”), has heretofore been filed, or transmitted
for filing, with the Commission (other than prospectuses filed pursuant to Rule 424(b) of the rules and regulations of the Commission under the Act, each in the form heretofore delivered to the Underwriters); and no objection pursuant to Rule
401(g)(2) to the use of the form of, or stop order suspending the effectiveness of, the Initial Registration Statement, any post-effective amendment thereto or any part thereof or the Rule 462(b) Registration Statement, if any, has been issued and
no proceeding for that purpose has been initiated or, to the knowledge of the Company, threatened by the Commission (the base prospectus filed as part of the Initial Registration Statement relating to the Securities, in the form in which it has most
recently been filed with the Commission on or prior to the date of this Agreement and including all documents incorporated by reference therein, is hereinafter called the “Basic Prospectus”; any preliminary prospectus (including any
preliminary prospectus supplement) relating to the Securities filed with the Commission pursuant to Rule 424(b) under the Act is hereinafter called a “Preliminary Prospectus”; the various parts of the Initial Registration Statement
 and the Rule 462(b) Registration Statement, if any, including all exhibits thereto and including any prospectus supplement relating to the Securities that is filed with the Commission and deemed by virtue of Rule 430B under the Act to be part of
the Initial Registration Statement, each as amended at the time such part of the Initial Registration Statement became effective or such part of the Rule 462(b) Registration Statement, if any, became or hereafter becomes effective, are hereinafter
collectively called the “Registration Statement”; the Basic Prospectus, as amended and supplemented by the Preliminary Prospectus and any Issuer Free Writing Prospectus (as defined below) immediately prior to the Applicable Time (as
defined in Section 1(c) hereof), is hereinafter called the “Pricing Prospectus”; the form of the final prospectus relating to the Securities filed with the Commission pursuant to Rule 424(b) under the Act in accordance with
Section 5(a) hereof is hereinafter called the “Prospectus”; any reference herein to the Basic Prospectus, the Pricing Prospectus, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents
incorporated by reference therein pursuant to Item 12 of Form S-3 under the Act, as of the date of such prospectus; any reference to any amendment or supplement to the Basic Prospectus, any Preliminary
Prospectus or the Prospectus shall be deemed to refer to and include any post-effective amendment to the Registration Statement, any prospectus supplement relating to the Securities filed with the Commission pursuant

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to Rule 424(b) under the Act and any documents filed under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and incorporated therein, in each case after the date
of the Basic Prospectus, such Preliminary Prospectus or the Prospectus, as the case may be; any reference to any amendment to the Registration Statement shall be deemed to refer to and include any annual report of the Company filed pursuant to
Section 13(a) or 15(d) of the Exchange Act after the effective date of the Registration Statement that is incorporated by reference in the Registration Statement; and any “issuer free writing prospectus” as defined in Rule 433 under
the Act relating to the Securities is hereinafter called an “Issuer Free Writing Prospectus”);
 (b) No order
preventing or suspending the use of any Preliminary Prospectus or any Issuer Free Writing Prospectus has been issued by the Commission, and each Preliminary Prospectus, at the time of filing thereof, conformed in all material respects to the
requirements of the Act and the Trust Indenture Act, and the rules and regulations of the Commission thereunder, and did not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary
to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided , however , that this representation and warranty shall not apply to any statements or omissions made in reliance upon
and in conformity with information furnished in writing to the Company by the Underwriters, such information consisting solely of the statements set forth in the second and third sentences of the third paragraph and the second sentence of the fourth
paragraph under the heading “Underwriting; Conflicts of Interest” in the Prospectus Supplement (such information, the “Underwriter Information”);

 (c) For the purposes of this Agreement, the “Applicable Time” is 3:41 p.m. (Eastern time) on the date of this
Agreement; the Pricing Prospectus as supplemented by the final term sheet prepared and filed pursuant to Section 5(a) hereof, taken together (collectively, the “Pricing Disclosure Package”) as of the Applicable Time, did not include
any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; and each Issuer Free Writing Prospectus
listed on Schedule II(a) hereto does not conflict with the information contained in the Registration Statement, the Pricing Prospectus or the Prospectus and each such Issuer Free Writing Prospectus, as supplemented by and taken together with
the Pricing Disclosure Package as of the Applicable Time and each Pricing Disclosure Package and Prospectus as of the Time of Delivery, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to
make the statements therein, in the light of the circumstances under which they were made, not misleading; provided , however , that this representation and warranty shall not apply to statements or omissions made in an Issuer Free
Writing Prospectus in reliance upon and in conformity with the Underwriter Information;

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 (d) The documents incorporated by reference in the Pricing Prospectus and
Prospectus, when they became effective or were filed with the Commission, as the case may be, conformed in all material respects to the requirements of the Act or the Exchange Act, as applicable, and the rules and regulations of the Commission
thereunder, and none of such documents contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading; and any further documents so filed
and incorporated by reference in the Prospectus or any further amendment or supplement thereto, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of
the Act or the Exchange Act, as applicable, and the rules and regulations of the Commission thereunder and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make
the statements therein not misleading; provided , however , that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with the Underwriter Information; and no such
documents were filed with the Commission since the Commission’s close of business on the business day immediately prior to the date of this Agreement and prior to the execution of this Agreement, except as set forth on Schedule II(b) hereto;

 (e) The Registration Statement conforms, and the Prospectus and any further amendments or supplements to the Registration
Statement and the Prospectus will conform, in all material respects to the requirements of the Act and the Trust Indenture Act and the rules and regulations of the Commission thereunder and do not and will not, as of the applicable effective date as
to each part of the Registration Statement and as of the applicable filing date as to the Prospectus and any amendment or supplement thereto, contain an untrue statement of a material fact or omit to state a material fact required to be stated
therein or necessary to make the statements therein (in case of the Prospectus only, in the light of the circumstances under which they were made) not misleading; provided , however , that this representation and warranty shall not apply
to (i) any statements or omissions made in reliance upon and in conformity with the Underwriter Information or (ii) any Statement of Eligibility (Form T-1) of the Trustee;

 (f) The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the
Commonwealth of Virginia, with power and authority (corporate and other) to own its properties and conduct its business as described in the Pricing Prospectus, and has been duly qualified as a foreign corporation for the transaction of business and
is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification, except where the failure to so qualify or be in good standing would not, individually
or in the aggregate, have a material adverse effect on the current or future financial position, stockholder’s equity or results of operations of the Company and its subsidiaries, considered as a whole (a “Material Adverse
Effect”). The Company is duly registered as a bank holding company under the Bank Holding Company Act of 1956, as amended (the “BHC Act”);

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 (g) (i) Neither the Company nor Santander Bank, N.A., a wholly-owned
subsidiary of the Company (the “Significant Subsidiary” or the “Bank”) has sustained since the date of the latest audited financial statements included or incorporated by reference in the Pricing Prospectus any material loss
or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the
Pricing Prospectus; and (ii) since the respective dates as of which information is given in the Registration Statement and the Pricing Prospectus, there has not been any material adverse change in the capital stock or long-term debt of the
Company or the Significant Subsidiary or any material adverse change, or any development involving a prospective material adverse change, in or affecting the general affairs, management, financial position, stockholders’ equity or results of
operations of the Company and its subsidiaries, considered as a whole, otherwise than as set forth or contemplated in the Pricing Prospectus;

 (h) The Company and the Significant Subsidiary have good and marketable title to all material real property and good and
marketable title to all material personal property owned by them, in each case free and clear of all liens, encumbrances, claims and defects and imperfections of title except such as are described in the Pricing Prospectus or such as do not
materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by the Company and the Significant Subsidiary, provided , however , that such material real property
and material personal property shall not include any property obtained by the Company or the Significant Subsidiary as the result of a foreclosure upon or a repossession of such property; and any material real property and buildings held under lease
by the Company and the Significant Subsidiary are held by them under valid, subsisting and enforceable leases with such exceptions as are not material and do not materially interfere with the use made and proposed to be made of such property and
buildings by the Company and the Significant Subsidiary;
 (i) The Bank has been duly constituted and is validly existing as
a national banking association under the laws of the United States and previously was a nationally-chartered savings bank chartered under the laws of the United States. The Bank is duly authorized to transact business and is in good standing in each
jurisdiction in which it owns or leases property of a nature, or transacts business of a type, that would make such authorization necessary, except where the failure to so qualify or be in good standing would not, individually or in the aggregate,
have a Material Adverse Effect;
 (j) The Bank is an insured depositary institution under the provisions of the Federal
Deposit Insurance Act, as amended (the “FDIC”), the deposit accounts of the Bank are insured up to applicable limits by the FDIC, all premiums and assessments required to be paid in connection therewith have been paid when due and no
proceedings for the termination or revocation of such insurance are pending or, to the knowledge of the Company, threatened;

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 (k) Other than as set forth or incorporated by reference in the Pricing
Prospectus, the Company and the Bank are in compliance in all material respects with all laws administered by the FDIC, Board of Governors of the Federal Reserve System (the “Federal Reserve Board”), the Office of the Comptroller of the
Currency (the “OCC”), the Consumer Financial Protection Bureau (the “CFPB”), and any other federal and state bank regulatory authorities (together with the FDIC, Federal Reserve Board, OCC and CFPB, the “Bank Regulatory
Authorities”) with jurisdiction over the Company and the Bank;
 (l) Other than as set forth or incorporated by
reference in the Pricing Prospectus, the Company is not subject to any order of the Federal Reserve Board which, as of the date hereof, prohibits the payment of dividends by it or any of its subsidiaries, other than those orders generally applicable
to similarly situated bank holding companies (including, without limitation, dividend payment limitations in connection with the Federal Reserve Board’s capital plan review process);

 (m) The Company has an authorized capitalization as set forth in the Pricing Prospectus, and all of the issued shares of
capital stock of the Company have been duly and validly authorized and issued and are fully paid and non-assessable; and all of the issued shares of capital stock of the Significant Subsidiary of the Company
have been duly and validly authorized and issued, are fully paid and non-assessable and, except for directors’ qualifying shares and except as otherwise set forth in the Pricing Prospectus, are owned
directly or indirectly by the Company, free and clear of all liens or encumbrances;
 (n) The Securities have been duly
authorized and, when issued, delivered and paid for at the Time of Delivery pursuant to this Agreement, will have been duly executed, authenticated, issued and delivered and, assuming the Securities are authenticated by the Trustee in accordance
with the terms of the Indenture, will constitute valid and legally binding obligations of the Company entitled to the benefits provided by the Indenture, under which they are to be issued; the Indenture has been duly authorized and duly qualified
under the Trust Indenture Act and, when executed and delivered by the Company and the Trustee, will constitute a valid and legally binding instrument, enforceable in accordance with its terms, subject, as to enforcement, to bankruptcy, insolvency,
fraudulent transfer, reorganization, moratorium and other laws of general applicability relating to or affecting creditors’ rights and to general equity principles (whether considered in a proceeding at law or in equity); and the Securities
and the Indenture will conform in all material respects to the descriptions thereof in the Pricing Disclosure Package and the Prospectus;

 (o) This Agreement has been duly authorized, executed and delivered by the Company;

 (p) The issue and sale of the Securities and the compliance by the Company with all of the provisions of the Securities, the
Indenture and this Agreement and the consummation of the transactions herein and therein contemplated will not materially conflict with or result in a material breach or violation of any of the terms or provisions of, or constitute a material
default under, any material indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to

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which any of the property or assets of the Company or any of its subsidiaries is subject, nor will such action result in any violation of the provisions of the Certificate of Incorporation or By-laws of the Company or material violation of any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over the Company or the Significant Subsidiary or any of
their properties; and no consent, approval, authorization, order, registration or qualification of or with any such court or governmental agency or body is required for the issue and sale of the Securities or the consummation by the Company of the
transactions contemplated by this Agreement or the Indenture except such as have been obtained under the Act and the Trust Indenture Act and such consents, approvals, authorizations, registrations or qualifications as may be required under state
securities or Blue Sky laws in connection with the purchase and distribution of the Securities by the Underwriters;
 (q)
Neither the Company, the Significant Subsidiary nor any agent acting on their behalf has taken or will take any action that is reasonably likely to cause the issuance, sale or delivery of the Securities or the application of the proceeds thereof by
the Company to violate Regulation T, U or X of the Federal Reserve Board or any other regulation of the Federal Reserve Board, in each case as in effect on the date hereof;

 (r) Other than as set forth or incorporated by reference in the Pricing Prospectus, there are no legal or governmental
proceedings pending to which the Company or the Significant Subsidiary is a party or of which any property of the Company or the Significant Subsidiary is the subject that is reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect;
 (s) Neither the Company nor the Significant Subsidiary is (i) (A) in the case of the Company, in
violation of its Articles of Incorporation, as amended, or (B) in the case of the Significant Subsidiary, in violation of its Articles of Association, as amended, (ii) in violation of its By-laws, as
amended, or (iii) in default in the performance or observance of any material obligation, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which it is a party
or by which it or any of its properties may be bound, except where such defaults under (iii) would not, individually or in the aggregate, have a Material Adverse Effect;

 (t) The (i) statements set forth in the Pricing Prospectus and the Prospectus under the caption “Description of the
Notes,” insofar as they purport to constitute a summary of the terms of the Securities, fairly summarize such provisions in all material respects and (ii) discussion set forth in the Pricing Prospectus and the Prospectus under the caption
“Material U.S. Federal Income Tax Consequences” insofar as it summarizes United States federal income tax law, and subject to the qualifications, exceptions, assumptions and limitations described therein, is accurate in all material
respects;
 (u) The Company is not and, after giving effect to the offering and sale of the Securities and the application
of the proceeds thereof, will not be required to register as an “investment company,” as such term is defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”);

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 (v) At the earliest time after the filing of the Initial Registration
Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) under the Act) of the Securities, the Company was not an “ineligible issuer” as defined in Rule 405 under
the Act;
 (w) Other than as set forth or incorporated by reference in the Pricing Prospectus, (i) the financial
statements of the Company and its consolidated subsidiaries, together with the related notes thereto, incorporated by reference in the Pricing Disclosure Package and the Prospectus present fairly, in all material respects, the consolidated financial
position of the Company and its subsidiaries as of and at the dates indicated and the results of their operations and cash flows for the periods specified and (ii) such financial statements have been prepared in conformity with generally
accepted accounting principles (“GAAP”) as applied in the United States applied on a consistent basis throughout the periods involved, except to the extent indicated in such financial statements or the related notes thereto. The selected
financial data and the summary financial information included in the Pricing Disclosure Package and the Prospectus present fairly, in all material respects, the information shown therein and have been compiled on a basis consistent with that of the
audited financial statements included in the Pricing Disclosure Package and the Prospectus;
 (x) (i) Each of (A) the
audited consolidated financial statements of Webster and its consolidated subsidiaries, together with the related notes thereto and (B) the interim unaudited consolidated financial statement of Webster and its consolidated subsidiaries,
together with the related notes thereto, in each case, incorporated by reference in the Pricing Disclosure Package and the Prospectus present fairly, in all material respects, the consolidated financial position of Webster and its subsidiaries as of
and at the dates indicated and the results of their operations and cash flows for the periods specified, (ii) such financial statements have been prepared in conformity with GAAP applied on a consistent basis throughout the periods involved,
except to the extent indicated in such financial statements or the related notes thereto, and (iii) the Company has complied in all respects with the obligations under the Exchange Act to file financial statements of Webster and its subsidiary
and affiliates in the Company’s filings under the Exchange Act incorporated by reference in the Pricing Disclosure Package and the Prospectus.

 (y) The unaudited pro forma condensed combined financial statements of the Company and Webster, together with the related notes
thereto (the “Pro Forma Financial Statements”), incorporated by reference in the Pricing Disclosure Package and the Prospectus have been prepared in accordance with the Commission’s rules and guidelines with respect to pro forma
financial statements and have been properly presented on the bases described therein, and the assumptions used in the preparation thereof are reasonable, the adjusted used therein are appropriate to give effect to the transactions referred to
therein, the pro forma financial information reflects the proper application of those adjustments to the historical financial statement amounts in the pro forma financial statements, and the Pro Forma Financial Statements present fairly, in all
material respects, the information contained therein. The Pro Forma Financial Statements comply as to form in all material respects with the applicable requirements of Article 11 of Regulation S-X under the
Securities Act.

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 (z) PricewaterhouseCoopers LLP, who has certified certain financial
statements of the Company and its subsidiaries and has audited the Company’s internal control over financial reporting and management’s assessment thereof, is an independent public accounting firm as required by the Act and the rules and
regulations of the Commission thereunder;
 (aa) KPMG LLP, who has certified certain financial statements of Webster and its
subsidiaries and has audited Webster’s internal control over financial reporting and management’s assessment thereof, is an independent public accounting firm as required by the Act and the rules and regulations of the Commission
thereunder;
 (bb) The Company maintains a system of internal control over financial reporting (as such term is defined in
Rule 13a-15(f) under the Exchange Act) that complies with the requirements of the Exchange Act and has been reasonably designed by the Company’s principal executive officer and principal financial
officer, or under their supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. The
Company’s internal control over financial reporting is effective and meets the criteria described in “Internal Control—Integrated Framework (2013)”, issued by the Committee of Sponsoring Organizations of the Treadway
Commission, and the Company is not aware of any material weaknesses in its internal control over financial reporting;
 (cc)
Since the date of the latest audited financial statements included or incorporated by reference in the Prospectus, there has been no change in the Company’s internal control over financial reporting that has materially affected, or is
reasonably likely to materially affect, the Company’s internal control over financial reporting;
 (dd) The Company
maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) under the Exchange Act) that comply with the requirements of the Exchange Act; such disclosure controls and procedures
have been reasonably designed to ensure that material information relating to the Company and its subsidiaries is made known to the Company’s principal executive officer and principal financial officer by others within those entities; and such
disclosure controls and procedures are effective in all material respects;
 (ee) Since December 31, 2025, there has
been no change in the Company’s disclosure controls and procedures that has materially affected, or is reasonably likely to materially affect, the Company’s disclosure controls and procedures;

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 (ff) The operations of the Company and its subsidiaries are and have been
conducted at all times in compliance with applicable federal recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the applicable money laundering statutes of all jurisdictions where the
Company or any of its subsidiaries conducts business, the rules and regulations thereunder and any related or similar rules, regulations or guidelines issued, administered or enforced by any governmental or regulatory agency (collectively, the
“Anti-Money Laundering Laws”) in all material respects and no action, suit or proceeding by or before any court or governmental or regulatory agency, authority or body or any arbitrator involving the Company or any of its subsidiaries
with respect to the Anti-Money Laundering Laws is pending or, to the knowledge of the Company, threatened, that would, individually or in the aggregate, be material to the Company;

 (gg) Neither the Company nor any of its subsidiaries, directors, officers or employees, nor, to the knowledge of the Company,
any agent, or affiliate or other person acting on behalf of the Company or any of its subsidiaries are currently the subject or the target of any sanctions administered or enforced by the U.S. Government, (including, without limitation, the Office
of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”) or the U.S. Department of State and including, without limitation, the designation as a “specially designated national” or “blocked
person”), the United Nations Security Council (“UNSC”), the European Union, His Majesty’s Treasury (“HMT”), or other relevant sanctions authority (collectively, “Sanctions”), nor is the Company or any
of its subsidiaries located, organized or resident in a country or territory that is the subject or the target of Sanctions, including, without limitation, the Crimea Region of Ukraine, the Kherson Region of Ukraine, the Zaporizhzhia Region of
Ukraine, the so-called Donetsk People’s Republic, the so-called Luhansk People’s Republic and any other Covered Region of Ukraine identified pursuant to
Executive Order 14065, Cuba, Iran, North Korea and Syria (each, a “Sanctioned Country”); and the Company will not directly or indirectly use the proceeds of the offering of the Securities hereunder, or lend, contribute or otherwise make
available such proceeds to any subsidiary, joint venture partner or other person or entity (i) to fund or facilitate any activities of or business with any person or entity that, at the time of such funding or facilitation and to the knowledge
of the Company, is the subject or the target of Sanctions or (ii) to fund or facilitate any activities of or business in any Sanctioned Country. For the past 10 years, the Company and its subsidiaries have not knowingly engaged in and are not
now knowingly engaged in any dealings or transactions with any person that at the time of the dealing or transaction is or was the subject or the target of Sanctions or with any Sanctioned Country;

 (hh) Neither the Company nor, to the knowledge of the Company, any of its subsidiaries, directors, officers, any of their
respective employees, agents, affiliates or any other person acting on behalf of the Company or any of its subsidiaries, has taken any action, directly or indirectly, that has violated any provision of the Foreign Corrupt Practices Act of 1977, as
amended (the “FCPA”), or any applicable law or regulation implementing the OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions. The Company and its subsidiaries have instituted, and
maintain and enforce, policies and procedures designed to promote and ensure compliance with all applicable anti-bribery and anti-corruption laws;

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 (ii) Except as would not, individually or in the aggregate, reasonably be
expected to have a Material Adverse Effect (i) each of the Company and its subsidiaries has filed all U.S. federal income and other material tax returns required to be filed through the date hereof, subject to permitted extensions, and has paid
all taxes due and owing thereon, other than those being contested in good faith and for which adequate reserves have been provided in accordance with generally accepted accounting principles, and (ii) except as otherwise disclosed in the
Pricing Disclosure Package and the Prospectus, no tax deficiency has been determined adversely against the Company or any of its subsidiaries or any of their respective properties or assets, nor does the Company have knowledge of any such tax
deficiencies;
 (jj) The interactive data in eXtensible Business Reporting Language included or incorporated by reference in
the Registration Statement, the Preliminary Prospectus, the Pricing Prospectus and the Prospectus accurately presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and
guidelines applicable thereto; and
 (kk) The Company and its subsidiaries have taken commercially reasonable measures to
maintain protections against unauthorized access to, or disruption or failure of, their information technology systems. To the Company’s knowledge, during the past twelve months, neither the Company nor any of its subsidiaries have been
subject to any material unauthorized access to their information technology systems or data maintained by them.
 2. Subject to the terms
and conditions and in reliance upon the representations and warranties herein set forth, the Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company
the principal amount of the Securities set forth opposite the name of such Underwriter in Schedule I hereto, at a purchase price of (i) 99.75% of the principal amount thereof for the 2030 Notes, (ii) 99.65% of the principal amount thereof for the
2032 Notes and (iii) 99.55% of the principal amount thereof for the 2037 Notes.
 3. It is understood that the several Underwriters propose
to offer the Securities for sale upon the terms and conditions set forth in the Pricing Disclosure Package and the Prospectus.
 4. The
Securities to be purchased by each Underwriter hereunder will be represented by one or more definitive global securities in book-entry form which will be deposited by or on behalf of the Company with The Depository Trust Company (“DTC”)
or its designated custodian. The Company will deliver the Securities to SanCap, for the account of each Underwriter, against payment by or on behalf of such Underwriter of the purchase price therefor by wire transfer of Federal (same-day) funds to the account

 12

specified by the Company to SanCap at least twenty-four hours in advance, by causing DTC to credit the Securities to the account of SanCap at DTC. The Company will cause the certificates
representing the Securities to be made available to SanCap for checking prior to the Time of Delivery (as defined below). The time and date of such delivery and payment shall be approximately 9:30 a.m., New York City time, on June 5, 2026 or such
other time and date as SanCap and the Company may agree upon in writing. Such time and date are herein called the “Time of Delivery.”

 (a) The documents to be delivered at the Time of Delivery by or on behalf of the parties hereto pursuant to Section 8
hereof, including the cross-receipt for the Securities and any additional documents requested by the Representatives pursuant to Section 8(i) hereof, will be delivered at the offices of Wachtell, Lipton, Rosen & Katz, 51 West 52 nd Street, New York, New York 10019 (the “Closing Location”), and the Securities will be delivered to the Trustee, all at the Time of Delivery. For the purposes of this Agreement,
“New York Business Day” shall mean each Monday, Tuesday, Wednesday, Thursday and Friday that is not a day on which banking institutions in New York City are generally authorized or obligated by law or executive order to close.

 5. The Company agrees with each of the Underwriters:

 (a) To prepare the Prospectus in a form approved by you and to file such Prospectus pursuant to Rule 424(b) under the Act not
later than the Commission’s close of business on the second business day following the date of this Agreement or such earlier time as may be required under the Act; to make no further amendment or any supplement to the Registration Statement,
the Basic Prospectus or the Prospectus prior to the Time of Delivery which shall be disapproved by you promptly after reasonable notice thereof; to advise you, promptly after it receives notice thereof, of the time when any amendment to the
Registration Statement has been filed or becomes effective or any amendment or supplement to the Prospectus has been filed and to furnish you with copies thereof; to prepare a final term sheet, containing solely a description of the Securities, in a
form approved by you in your reasonable discretion and to file such term sheet pursuant to Rule 433(d) under the Act within the time required by such rule; to file promptly all other material required to be filed by the Company with the
Commission pursuant to Rule 433(d) under the Act; to file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the
Exchange Act subsequent to the date of the Prospectus and for so long as the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is required in connection with the offering or sale of the Securities; to
advise you, promptly after it receives notice thereof, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of any Preliminary Prospectus or other prospectus in respect of the Securities, of the
suspension of the qualification of the Securities for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose, or of any request by the Commission for the amending or supplementing of the
Registration Statement or the Prospectus or for additional information; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of any Preliminary Prospectus or other prospectus or suspending any such
qualification, to promptly use its best efforts to obtain the withdrawal of such order;

 13

 (b) Promptly from time to time to take such action as you may reasonably
request to qualify the Securities for offering and sale under the securities laws of such jurisdictions as you may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long
as may be necessary to complete the distribution of the Securities, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation, to file a general consent to service of process in any
jurisdiction or to become subject to taxation in any jurisdiction in which it is not otherwise subject;
 (c) If by the
third anniversary (the “Renewal Deadline”) of the initial effective date of the Registration Statement, any of the Securities remain unsold by the Underwriters, the Company will file, if it has not already done so and is eligible to do
so, a new shelf registration statement relating to the Securities, in a form reasonably satisfactory to you and will use its best efforts to cause such registration statement to be declared effective within 180 days after the Renewal Deadline. The
Company will take all other action necessary or appropriate to permit the public offering and sale of the Securities to continue as contemplated in the expired registration statement relating to the Securities. References herein to the Registration
Statement shall include such new automatic shelf registration statement or such new shelf registration statement, as the case may be;

 (d) Prior to 10:00 a.m., New York City time, on the New York Business Day next succeeding the date of this Agreement and from
time to time, to use its reasonable best efforts to furnish the Underwriters with electronic copies of the Prospectus in New York City in such quantities as you may reasonably request, and, if the delivery of a prospectus (or in lieu thereof, the
notice referred to in Rule 173(a) under the Act) is required at any time prior to the expiration of nine months after the time of issue of the Prospectus in connection with the offering or sale of the Securities and if at such time any event shall
have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the
circumstances under which they were made when such Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is delivered, not misleading, or, if for any other reason it shall be necessary during such same period to amend
or supplement the Prospectus or to file under the Exchange Act any document incorporated by reference in the Prospectus in order to comply with the Act, the Exchange Act or the Trust Indenture Act, to notify you and upon your request to file such
document and to prepare and furnish without charge to each Underwriter and to any dealer in securities as many written and electronic copies as you may from time to time reasonably request of an amended Prospectus or a supplement to the Prospectus
which will correct such statement or omission or effect such compliance; and in case any Underwriter is required to deliver a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) in connection with sales of any of the
Securities

 14

at any time nine months or more after the time of issue of the Prospectus, upon your request but at the expense of such Underwriter, to prepare and deliver to such Underwriter as many written and
electronic copies as you may request of an amended or supplemented Prospectus complying with Section 10(a)(3) of the Act;

 (e) To make generally available to its security holders as soon as practicable, but in any event not later than sixteen months
after the effective date of the Registration Statement (as defined in Rule 158(c) under the Act), an earnings statement of the Company and its subsidiaries (which need not be audited) complying with Section 11(a) of the Act and the rules and
regulations of the Commission thereunder (including, at the option of the Company, Rule 158 under the Act);
 (f) Without
the prior written consent of the Representatives, during the period beginning from the date hereof and ending at the Time of Delivery, not to offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise
transfer or dispose of, directly or indirectly, or file with the Commission a registration statement under the Act relating to any securities of the Company that are substantially similar to the Securities, or publicly disclose the intention to make
any offer, sale, pledge, disposition or filing;
 (g) If the Company elects to rely upon Rule 462(b), the Company shall file
a Rule 462(b) Registration Statement with the Commission in compliance with Rule 462(b) by 10:00 p.m., Washington, D.C. time, on the date of this Agreement, and the Company shall at the time of filing either pay the Commission the filing fee for the
Rule 462(b) Registration Statement or give irrevocable instructions for the payment of such fee pursuant to Rule 111(b) under the Act; and

 (h) To use the net proceeds received by the Company from the sale of the Securities in the manner specified in the Pricing
Prospectus under the caption “Use of Proceeds.”
 6. (a) (i)The Company represents and agrees that, other than the final term
sheet prepared and filed pursuant to Section 5(a) hereof, without the prior consent of the Representatives, it has not made and will not make any offer relating to the Securities that would constitute a “free writing prospectus” as
defined in Rule 405 under the Act;
 (ii) each Underwriter represents and agrees that, without the prior consent of the
Company and the Representatives, other than one or more term sheets relating to the Securities containing customary information (which, in their final form, will not be inconsistent with the final term sheet) and conveyed to purchasers of
Securities, it has not made and will not make any offer relating to the Securities that would constitute a free writing prospectus; and

 15

 (iii) any such free writing prospectus the use of which has been consented
to by the Company and the Representatives (including the final term sheet prepared and filed pursuant to Section 5(a) hereof) is listed on Schedule II(a) hereto;

 (b) The Company has complied and will comply with the requirements of Rule 433 under the Act applicable to any Issuer Free
Writing Prospectus, including timely filing with the Commission or retention where required and legending; and
 (c) The
Company agrees that if, at any time following issuance of an Issuer Free Writing Prospectus and prior to the Time of Delivery, any event occurred or occurs as a result of which such Issuer Free Writing Prospectus would conflict with the information
in the Registration Statement, the Pricing Prospectus or the Prospectus or would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances
then prevailing, not misleading, the Company will give prompt notice thereof to the Representatives and, if requested by the Representatives, will prepare and furnish without charge to each Underwriter an Issuer Free Writing Prospectus or other
document that will correct such conflict, statement or omission; provided , however , that this representation and warranty shall not apply to any statements or omissions in an Issuer Free Writing Prospectus made in reliance upon and in
conformity with the Underwriter Information.
 7. The Company covenants and agrees with the several Underwriters that the Company will pay
or cause to be paid the following: (i) the fees, disbursements and expenses of the Company’s counsel and accountants in connection with the registration of the Securities under the Act and all other expenses in connection with the
preparation, printing, distribution, reproduction and filing of the Registration Statement, the Basic Prospectus, any Preliminary Prospectus, any Issuer Free Writing Prospectus and the Prospectus and amendments and supplements thereto and the
mailing and delivering of copies thereof to the Underwriters and dealers; (ii) the cost of printing or producing this Agreement, the Indenture, any Blue Sky Memorandum, closing documents (including any compilations thereof) and any other
documents in connection with the offering, purchase, sale and delivery of the Securities; (iii) all expenses in connection with the qualification of the Securities for offering and sale under state securities laws as provided in
Section 5(b) hereof, including the reasonable fees and disbursements of counsel for the Underwriters in connection with such qualification and in connection with the Blue Sky survey(s); (iv) any fees charged by securities rating services for
rating the Securities; (v) any filing fees incident to, and the fees and disbursements of counsel for the Underwriters in connection with, any required reviews by the Financial Industry Regulatory Authority, Inc. of the terms of the sale of the
Securities; (vi) the cost of preparing certificates for the Securities; (vii) the cost and charges of any transfer agent or registrar or dividend disbursing agent; (viii) the fees and expenses of the Trustee and any agent of the
Trustee and the fees and disbursements of counsel for the Trustee in connection with the Indenture and the Securities; and (ix) all other costs and expenses incident to the performance of its obligations hereunder that are not otherwise
specifically provided for in this Section. It is understood, however, that, except as provided in this Section, and Sections 9 and 12 hereof, the Underwriters will pay all of their own costs and expenses, including the fees of their counsel,
transfer taxes on resale of any of the Securities by them, and any advertising expenses connected with any offers they may make.

 16

 8. The obligations of the Underwriters hereunder shall be subject to the condition that all
representations and warranties and other statements of the Company herein are, at and as of the Time of Delivery, true and correct, the condition that the Company shall have performed all of its obligations hereunder theretofore to be performed, and
the following additional conditions:
 (a) The Prospectus shall have been filed with the Commission pursuant to Rule 424(b)
under the Act within the applicable time period prescribed for such filing by the rules and regulations under the Act and in accordance with Section 5(a) hereof; the final term sheet contemplated by Section 5(a) hereof, and any other
material required to be filed by the Company pursuant to Rule 433(d) under the Act shall have been filed with the Commission within the applicable time period prescribed for such filings by Rule 433; if the Company has elected to rely upon Rule
462(b) under the Act, the Rule 462(b) Registration Statement shall have become effective by 10:00 p.m., Washington, D.C. time, on the date of this Agreement; no stop order suspending the effectiveness of the Registration Statement or any part
thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; no stop order suspending or preventing the use of the Prospectus or any Issuer Free Writing Prospectus shall have been
initiated or, to the knowledge of the Company, threatened by the Commission; and all requests for additional information on the part of the Commission shall have been complied with to the reasonable satisfaction of the Representatives;

 (b) Latham & Watkins LLP, counsel for the Underwriters, shall have furnished to you such written opinion or opinions,
dated the Time of Delivery, in form and substance reasonably satisfactory to you, with respect to such matters as the Underwriters may reasonably require, and such counsel shall have received such papers and information as they may reasonably
request to enable them to pass upon such matters;
 (c) (i) Wachtell, Lipton, Rosen & Katz, special counsel for the
Company, shall have furnished to you their written opinion to the effect set forth in Annex I(a), dated as of the Time of Delivery, in form and substance reasonably satisfactory to you and (ii) Lucosky Brookman LLP, Virginia counsel for the
Company, shall have furnished to you their written opinion to the effect set forth in Annex I(b), dated as of the Time of Delivery, in form and substance reasonably satisfactory to you;

 (d) (i) On the date of the Prospectus substantially concurrently with the execution of this Agreement, at 9:30 a.m., New York
City time, on the effective date of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement and also at the Time of Delivery, PricewaterhouseCoopers LLP shall have furnished to you a letter or
letters, dated the respective dates of delivery thereof, in form and substance reasonably satisfactory to you, confirming that they are an independent registered public accounting firm within the meaning of the Act and containing statements and
information of the type customarily included in accountants’ “comfort letters” to

 17

underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the Pricing Disclosure Package and the Prospectus; provided, that
the letter furnished on and dated as of the Time of Delivery shall use a “cut-off” date no more than two business days prior to the Time of Delivery; and

 (ii) On the date of the Prospectus at a time prior to the execution of this Agreement, at 9:30 a.m., New York City time, on the effective date
of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement and also at the Time of Delivery, the Company shall have furnished to the Representatives a certificate, dated the respective dates of
delivery thereof and addressed to the Underwriters, of its treasurer with respect to certain financial data contained in the Pricing Disclosure Package and the Prospectus, providing “management comfort” with respect to such information,
in form and substance reasonably satisfactory to you.
 (e) On the date of the Prospectus substantially concurrently with
the execution of this Agreement, at 9:30 a.m., New York City time, on the effective date of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement and also at the Time of Delivery, KPMG LLP shall
have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance reasonably satisfactory to you, confirming that they are an independent registered public accounting firm within the meaning of the Act
and containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements of Webster and certain financial information contained in the
Registration Statement, the Pricing Disclosure Package and the Prospectus; provided, that the letter furnished on and dated as of the Time of Delivery shall use a “cut-off” date no more than two
business days prior to the Time of Delivery.
 (f) (i) Neither the Company nor the Significant Subsidiary shall have
sustained since the date of the latest audited financial statements included or incorporated by reference in the Pricing Prospectus any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by
insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Prospectus, and (ii) since the respective dates as of which information is given in the Pricing
Prospectus there shall not have been any material change in the capital stock or long-term debt of the Company or the Significant Subsidiary or any change, or any development involving a prospective change, in
or affecting the general affairs, management, financial position, stockholders’ equity or results of operations of the Company and its subsidiaries, otherwise than as set forth or contemplated in the Pricing Prospectus, the effect of which, in
any such case described in clause (i) or (ii), is in your judgment so material and adverse as to make it impracticable or inadvisable to proceed with the public offering or the delivery of the Securities on the terms and in the manner
contemplated in the Prospectus;

 18

 (g) On or after the Applicable Time (i) no downgrading shall have
occurred in the rating accorded the Company’s debt securities or preferred stock by any “nationally recognized statistical rating organization”, as that term is defined by the Commission for purposes of Section 3(a)(62) under
the Exchange Act, and (ii) no such organization shall have publicly announced that it has under surveillance or review (other than an announcement with possible implications of an upgrading) its rating of any of the Company’s debt
securities or preferred stock;
 (h) On or after the Applicable Time there shall not have occurred any of the following:
(i) a suspension or material limitation in trading in securities generally on the New York Stock Exchange; (ii) a suspension or material limitation in trading in the Company’s securities on the New York Stock Exchange;
(iii) a general moratorium on commercial banking activities declared by either Federal or New York State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States;
(iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political
or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (iv) or (v) in your judgment makes it impracticable or inadvisable to proceed with the public offering or the delivery of the
Securities on the terms and in the manner contemplated in the Prospectus;
 (i) The Company shall have complied with the
provisions of Section 5(d) hereof with respect to the furnishing of prospectuses; and
 (j) The Company shall have
furnished or caused to be furnished to you at the Time of Delivery certificates of officers of the Company reasonably satisfactory to you as to the accuracy of the representations and warranties of the Company herein at and as of such Time of
Delivery, as to the performance by the Company of all of its obligations hereunder to be performed at or prior to such Time of Delivery, as to the matters set forth in subsections (a) and (f) of this Section and as to such other matters as you
may reasonably request.
 9. The Company will indemnify and hold harmless each Underwriter against any losses, claims, damages or
liabilities, joint or several, to which such Underwriter may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or
alleged untrue statement of a material fact contained in the Registration Statement, the Basic Prospectus, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, any “issuer
information” filed or required to be filed pursuant to Rule 433(d) under the Act or any Issuer Free Writing Prospectus, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, and will reimburse each Underwriter for any legal or other expenses reasonably incurred by such Underwriter in connection with investigating or defending any such action or claim

 19

as such expenses are incurred; provided , however , that the Company shall not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or
is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in the Registration Statement, the Basic Prospectus, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or
supplement thereto, or any Issuer Free Writing Prospectus, in reliance upon and in conformity with Underwriter Information.

 (a) Each Underwriter will severally and not jointly indemnify and hold harmless the Company against any losses, claims, damages
or liabilities to which the Company may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement
of a material fact contained in the Registration Statement, the Basic Prospectus, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus, or arise out of or
are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement
or alleged untrue statement or omission or alleged omission was made in the Registration Statement, the Basic Prospectus, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer
Free Writing Prospectus, in reliance upon and in conformity with Underwriter Information; and will reimburse the Company for any legal or other expenses reasonably incurred by the Company in connection with investigating or defending any such action
or claim as such expenses are incurred.
 (b) Promptly after receipt by an indemnified party under subsection (a) or
(b) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing of the commencement
thereof; but the omission so to notify the indemnifying party shall not relieve it from any liability which it may have to any indemnified party otherwise than under such subsection. In case any such action shall be brought against any indemnified
party and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to
assume the defense thereof, with counsel reasonably satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and, after notice from the indemnifying party to such
indemnified party of its election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently
incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation. Notwithstanding the foregoing, any indemnified party shall have the right to retain its own counsel, but the fees and expenses
of such counsel shall be at the expense

 20

of such indemnified party unless (i) the indemnifying party and the indemnified party shall have mutually agreed to the contrary; (ii) the indemnifying party has failed within a
reasonable time to retain counsel reasonably satisfactory to the indemnified party; (iii) the indemnified party shall have reasonably concluded that there may be legal defenses available to it that are different from or in addition to those
available to the indemnifying party; or (iv) the named parties in any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would
be inappropriate due to actual or potential differing interest between them. It is understood and agreed that the indemnifying party shall not, in connection with any proceeding or related proceeding, be liable for the fees and expenses of more than
one separate firm (in addition to any one firm of local counsel for each jurisdiction) for all indemnified parties, and that all such fees and expenses of such separate counsel shall be reimbursed as they are incurred. Any such separate firm for any
Underwriter, its affiliates, directors and officers and any control persons of such Underwriter shall be designated in writing by the Underwriter and any such separate firm for the Company, its directors, its officers who signed the Registration
Statement and any control persons of the Company shall be designated in writing by the Company. The indemnifying party shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or
if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify each indemnified party from and against any loss or liability by reason of such settlement or judgment. No indemnifying party shall, without the written
consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder
(whether or not the indemnified party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the indemnified party from all liability arising out of such
action or claim and (ii) does not include any admission of fault, culpability or a failure to act, by or on behalf of any indemnified party.

 (c) If the indemnification provided for in this Section 9 is unavailable to or insufficient to hold harmless an
indemnified party under subsection (a) or (b) above in respect of any losses, claims, damages or liabilities (or actions in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by
such indemnified party as a result of such losses, claims, damages or liabilities (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on
the other from the offering of the Securities. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the indemnified party failed to give the notice required under subsection
(c) above, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the
one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or

 21

actions in respect thereof), as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be
deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in
the table on the cover page of the Prospectus. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company on the one hand or the Underwriters on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company
and the Underwriters agree that it would not be just and equitable if contribution pursuant to this subsection (d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any
other method of allocation which does not take account of the equitable considerations referred to above in this subsection (d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages or liabilities (or actions
in respect thereof) referred to above in this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Securities underwritten by it and distributed to the public were offered
to the public exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within
the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this subsection (d) to contribute are several in
proportion to their respective underwriting obligations and not joint.
 (d) The obligations of the Company under this
Section 9 shall be in addition to any liability that the Company may otherwise have and shall extend, upon the same terms and conditions, to each director, officer, employee and affiliate of each Underwriter and to each person, if any, who
controls any Underwriter within the meaning of the Act and each broker dealer affiliate of any Underwriter; and the obligations of the Underwriters under this Section 9 shall be in addition to any liability which the respective Underwriters may
otherwise have and shall extend, upon the same terms and conditions, to each director, officer, employee and affiliate of the Company and to each person, if any, who controls the Company within the meaning of the Act.

 10. If any Underwriter shall default in its obligation to purchase the Securities that it has agreed to purchase hereunder, you may, in your
discretion and without relieving any defaulting Underwriter from liability for its default, arrange for you or another party or other parties to purchase such Securities on the terms contained herein. If within
 thirty-six hours after such default by any Underwriter you do not arrange for the purchase of such

 22

Securities, then the Company shall be entitled to a further period of thirty-six hours within which to procure another party or other parties satisfactory
to you to purchase such Securities on such terms. In the event that, within the respective prescribed periods, you notify the Company that you have so arranged for the purchase of such Securities, or the Company notifies you that it has so arranged
for the purchase of such Securities, you or the Company shall have the right to postpone the Time of Delivery for a period of not more than seven days, in order to effect whatever changes may thereby be made necessary in the Registration Statement
or the Prospectus, or in any other documents or arrangements, and the Company agrees to file promptly any amendments or supplements to the Registration Statement or the Prospectus which in your opinion may thereby be made necessary. The term
“Underwriter” as used in this Agreement shall include any person substituted under this Section with like effect as if such person had originally been a party to this Agreement with respect to such Securities.

 (a) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters
by you and the Company as provided in subsection (a) above, the aggregate principal amount of such Securities which remains unpurchased does not exceed one-eleventh of the aggregate principal amount of
all the Securities, then the Company shall have the right to require each non-defaulting Underwriter to purchase the principal amount of Securities which such Underwriter agreed to purchase hereunder and, in
addition, to require each non-defaulting Underwriter to purchase its pro rata share (based on the principal amount of Securities which such Underwriter agreed to purchase hereunder) of the Securities of such
defaulting Underwriter or Underwriters for which such arrangements have not been made; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

 (b) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters
by you and the Company as provided in subsection (a) above, the aggregate principal amount of such Securities which remains unpurchased exceeds one-eleventh of the aggregate principal amount of all the
Securities, or if the Company shall not exercise the right described in subsection (b) above to require non-defaulting Underwriters to purchase the Securities of a defaulting Underwriter or Underwriters,
then this Agreement shall thereupon terminate, without liability on the part of any non-defaulting Underwriter to the Company and without any liability on the part of the Company to any Underwriter, except for
the expenses to be borne by the Company and the Underwriters as provided in Section 7 hereof and the indemnity and contribution agreements in Section 9 hereof; but nothing herein shall relieve a defaulting Underwriter from liability for
its default.
 11. The respective indemnities, agreements, representations, warranties and other statements of the Company and the several
Underwriters, as set forth in this Agreement or made by or on behalf of them, respectively, pursuant to this Agreement, shall remain in full force and effect, regardless of any investigation (or any statement as to the results thereof) made by or on
behalf of any Underwriter or any controlling person of any Underwriter, or the Company, or any officer or director or controlling person of the Company, and shall survive delivery of and payment for the Securities.

 23

 12. If this Agreement shall be terminated pursuant to Section 10 hereof, the Company
shall not then be under any liability to any Underwriter except as provided in Sections 7, 9 and 22 hereof; but, if for any other reason (excluding the default by one or more of the Underwriters in its or their respective obligations), the
Securities are not delivered by or on behalf of the Company as provided herein, the Company will reimburse the Underwriters through SanCap for all reasonable
 out-of-pocket expenses approved in writing by SanCap, including reasonable fees and disbursements of counsel, reasonably incurred by the Underwriters in making
preparations for the purchase, sale and delivery of the Securities, but the Company shall then be under no further liability to any Underwriter except as provided in Sections 7, 9 and 22 hereof.

 13. In all dealings hereunder, you shall act on behalf of each of the Underwriters, and the parties hereto shall be entitled to act and rely
upon any statement, request, notice or agreement on behalf of any Underwriter made or given by the Representatives on behalf of the Underwriters.

 All statements, requests, notices and agreements hereunder shall be in writing, and if to the Underwriters shall be delivered or sent by mail,
telex or facsimile transmission to the Underwriters in the care of the Representatives via (i) Santander US Capital Markets LLC, 437 Madison Avenue, New York, New York 10022, Attention: Debt Capital Markets, facsimile: (212) 407-0930; (ii) BofA Securities, Inc., 114 W. 47 th Street,
 NY8-114-07-01, New York, New York 10036, Attention: High Grade Transaction Management/Legal, facsimile: (212) 901-7881; (iii) Citigroup Global Markets Inc., 388 Greenwich Street, New York, New York 10013, Attention: General Counsel, facsimile number: +1 (646) 291-1469; (iv) J.P.
Morgan Securities LLC, 270 Park Avenue, New York, New York 10017, Attention: Legal Department; (v) Morgan Stanley & Co. LLC, 1585 Broadway, New York, New York 10036, Attention: Equity Syndicate Desk, with a copy to the Legal
Department; and (vi) RBC Capital Markets, LLC, 200 Vesey Street, 8th Floor New York, New York, 10281, Attention: Legal Department, and if to the Company shall be delivered or sent by mail, telex or facsimile transmission to the address of the
Company set forth in the Registration Statement, Attention: Chief Legal Officer; provided , however , that any notice to an Underwriter pursuant to Section 9(c) hereof shall be delivered or sent by mail, telex or facsimile
transmission to such Underwriter at its address set forth in its Underwriters’ questionnaire, or telex constituting such questionnaire, which address will be supplied to the Company by you upon request. Any such statements, requests, notices
or agreements shall take effect upon receipt thereof.
 In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include
the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients.

 24

 14. This Agreement shall be binding upon, and inure solely to the benefit of, the
Underwriters, the Company and, to the extent provided in Sections 9 and 11 hereof, the officers and directors of the Company and each person who controls the Company or any Underwriter, and their respective heirs, executors, administrators,
successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. No purchaser of any of the Securities from any Underwriter shall be deemed a successor or assign by reason merely of such purchase.

 15. Time shall be of the essence of this Agreement. As used herein, the term “business day” shall mean any day when the
Commission’s office in Washington, D.C. is open for business.
 16. The Company acknowledges and agrees that (i) the purchase
and sale of the Securities pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other, (ii) in connection
therewith and with the process leading to such transaction each Underwriter is acting solely as a principal and not the agent or fiduciary of the Company, (iii) no Underwriter has assumed an advisory or fiduciary responsibility in favor of the
Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) or any other obligation to the Company except the
obligations expressly set forth in this Agreement and (iv) the Company has consulted its own legal and financial advisors to the extent it deemed appropriate. The Company agrees that it will not claim that the Underwriters, or any of them, has
rendered advisory services of any nature or respect, or owes a fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

 17. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriters, or
any of them, with respect to the subject matter hereof.
 18. THIS AGREEMENT AND ANY MATTERS RELATED TO THIS TRANSACTION SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICT OF LAWS THAT WOULD RESULT IN THE APPLICATION OF ANY LAW OTHER THAN THE LAWS OF THE STATE OF NEW YORK. The Company agrees
that any suit or proceeding arising in respect of this agreement or our engagement will be tried exclusively in the U.S. District Court for the Southern District of New York or, if that court does not have subject matter jurisdiction, in any state
court located in The City and County of New York and the Company agrees to submit to the jurisdiction of, and to venue in, such courts.

 19. THE COMPANY AND EACH OF THE UNDERWRITERS HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT
TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

 25

 20. This Agreement may be executed by any one or more of the parties hereto in any number of
counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same instrument. Any signature (including, without limitation, (x) any electronic symbol or process attached to, or
associated with, a contract or other record and adopted by a person with the intent to sign, authenticate or accept such contract or record and (y) any facsimile, E-pencil or .pdf signature) hereto or to
any other certificate, agreement or document related to this Agreement, and any contract formation or record-keeping, in each case, through electronic means, shall have the same legal validity and enforceability as a manually executed signature or
use of a paper-based record-keeping system to the fullest extent permitted by applicable law. For the avoidance of doubt, the foregoing also applies to any amendment, extension or renewal of this Agreement. Each of the parties to this Agreement
represents and warrants to the other parties that it has the corporate capacity and authority to execute this Agreement through electronic means and there are no restrictions for doing so in that party’s constitutive documents.

 21. Notwithstanding anything herein to the contrary, the Company is authorized to disclose to any persons the U.S. federal and state income
tax treatment and tax structure of the potential transaction and all materials of any kind (including tax opinions and other tax analyses) provided to the Company relating to that treatment and structure, without the Underwriters imposing any
limitation of any kind. For this purpose, “tax structure” is limited to any facts that may be relevant to that treatment.
 22.
Recognition of the U.S. Special Resolution Regimes.
 (a) In the event that any Underwriter that is a Covered Entity becomes
subject to a proceeding under a U.S. Special Resolution Regime, the transfer from such Underwriter of this Agreement, and any interest and obligation in or under this Agreement, will be effective to the same extent as the transfer would be effective
under the U.S. Special Resolution Regime if this Agreement, and any such interest and obligation, were governed by the laws of the United States or a state of the United States.

 (b) In the event that any Underwriter that is a Covered Entity or a BHC Act Affiliate of such Underwriter becomes subject to a
proceeding under a U.S. Special Resolution Regime, Default Rights under this Agreement that may be exercised against such Underwriter are permitted to be exercised to no greater extent than such Default Rights could be exercised under the U.S.
Special Resolution Regime if this Agreement were governed by the laws of the United States or a state of the United States.

 (c) As used in this section:

 (i) “BHC Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted
in accordance with, 12 U.S.C. § 1841(k).
 (ii) “Covered Entity” means any of the following:

 (1) a “covered entity” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b);

 26

 (2) a “covered bank” as that term is defined in, and
interpreted in accordance with, 12 C.F.R. § 47.3(b); or
 (3) a “covered FSI” as that term is defined in,
and interpreted in accordance with, 12 C.F.R. § 382.2(b).
 (iii) “Default Right” has the meaning assigned
to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable.

 (iv) “U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations
promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

 [ Signature Page Follows ]

 27

 If the foregoing is in accordance with your understanding, please sign and return to us
counterparts hereof, and upon the acceptance hereof by you, on behalf of each of the Underwriters, this letter and such acceptance hereof shall constitute a binding agreement between each of the Underwriters and the Company. It is understood that
your acceptance of this letter on behalf of each of the Underwriters is pursuant to the authority set forth in a form of Agreement among Underwriters, the form of which shall be submitted to the Company for examination upon request, but without
warranty on your part as to the authority of the signers thereof.

 Very truly yours,

 SANTANDER HOLDINGS USA, INC.

 By:

 /s/ Corey Henry

 Name: Corey Henry

 Title: Senior Vice President

 [Signature Page to
Underwriting Agreement]

 Accepted as of the date hereof:

 SANTANDER US CAPITAL MARKETS LLC

 By:

 /s/ Richard Zobkiw

 Name: Richard Zobkiw

 Title: Executive Director

 [Signature Page to
Underwriting Agreement]

 Accepted as of the date hereof:

 BOFA SECURITIES, INC.

 By:

 /s/ Anthony Aceto

 Name: Anthony Aceto

 Title: Managing Director

 [Signature Page to
Underwriting Agreement]

 Accepted as of the date hereof:

 CITIGROUP GLOBAL MARKETS INC.

 By:

 /s/ Adam D. Bordner

 Name: Adam D. Bordner

 Title: Managing Director

 [Signature Page to
Underwriting Agreement]

 Accepted as of the date hereof:

 J.P. MORGAN SECURITIES LLC

 By:

 /s/ Stephen L. Sheiner

 Name: Stephen L. Sheiner

 Title: Executive Director

 [Signature Page to
Underwriting Agreement]

 Accepted as of the date hereof:

 MORGAN STANLEY & CO. LLC

 By:

 /s/ Hector Vazquez

 Name: Hector Vazquez

 Title: Managing Director

 [Signature Page to
Underwriting Agreement]

 Accepted as of the date hereof:

 RBC CAPITAL MARKETS, LLC

 By:

 /s/ Jay Anderson

 Name: Jay Anderson

 Title: Managing Director & Head of US FIG DCM

 [Signature Page to
Underwriting Agreement]

 SCHEDULE I

 Underwriters

 Amount of

 2030 Notes to
 be
Purchased

 Amount of 2032
Notes to be
Purchased

 Amount of

 2037 Notes to
be Purchased

 Santander US Capital Markets LLC

 $
 490,000,000

 $
 367,500,000

 $
 367,500,000

 BofA Securities, Inc.

 90,000,000

 67,500,000

 67,500,000

 Citigroup Global Markets Inc.

 90,000,000

 67,500,000

 67,500,000

 J.P. Morgan Securities LLC

 90,000,000

 67,500,000

 67,500,000

 Morgan Stanley & Co. LLC

 90,000,000

 67,500,000

 67,500,000

 RBC Capital Markets, LLC

 90,000,000

 67,500,000

 67,500,000

 Blaylock Van, LLC

 20,000,000

 15,000,000

 15,000,000

 Lloyds Securities Inc.

 20,000,000

 15,000,000

 15,000,000

 MUFG Securities Americas Inc.

 20,000,000

 15,000,000

 15,000,000

 Total

 $
 1,000,000,000

 $
 750,000,000

 $
 750,000,000

 SCHEDULE II(a)

 ISSUER FREE WRITING PROSPECTUSES
 Final Pricing
Terms and Conditions dated June 2, 2026.
 [Attached hereto.]

 SCHEDULE II(b)

 None.

 ANNEX I(a)

 Form of Wachtell, Lipton, Rosen & Katz Opinions

 [Attached hereto.]

 ANNEX I(b)

 Form of Lucosky Brookman LLP Opinions

 [Attached hereto.]

EX-4.3 · d297610dex43.htm

EX-4.3
 3
 d297610dex43.htm
 EX-4.3

 Exhibit 4.3

 SANTANDER HOLDINGS USA, INC.

 Company
 to

 DEUTSCHE BANK TRUST COMPANY AMERICAS

 Trustee
 Thirty-Seventh
Supplemental Indenture
 SENIOR DEBT SECURITIES

 Dated as of June 5, 2026

 TABLE OF CONTENTS

 ARTICLE 1 SCOPE OF THIRTY-SEVENTH SUPPLEMENTAL INDENTURE

 2

 Section 1.01

 Scope

 2

 ARTICLE 2 DEFINITIONS

 2

 Section 2.01

 Definitions and Other Provisions of General Application

 2

 ARTICLE 3 FORM AND TERMS OF THE 2030 NOTES

 5

 Section 3.01

 Form and Dating

 5

 Section 3.02

 Terms of the Notes

 5

 ARTICLE 4 FORM AND TERMS OF THE 2032 NOTES

 18

 Section 4.01

 Form and Dating

 18

 Section 4.02

 Terms of the Notes

 18

 ARTICLE 5 FORM AND TERMS OF THE 2037 NOTES

 31

 Section 5.01

 Form and Dating

 31

 Section 5.02

 Terms of the Notes

 31

 ARTICLE 6 SUPPLEMENTAL INDENTURES

 44

 Section 6.01

 Supplemental Indentures

 44

 ARTICLE 7 MISCELLANEOUS

 44

 Section 7.01

 Trust Indenture Act of 1939

 44

 Section 7.02

 Governing Law

 44

 Section 7.03

 Duplicate Originals; Counterparts

 44

 Section 7.04

 Separability

 44

 Section 7.05

 Ratification

 44

 Section 7.06

 Effectiveness

 45

 Section 7.07

 Successors

 45

 Section 7.08

 Trustee’s Disclaimer

 45

 EXHIBIT A – Form of 5.040%
 Fixed-to-Floating Rate Senior Note due 2030
 EXHIBIT B – Form of
5.220% Fixed-to-Floating Rate Senior Notes due 2032
 EXHIBIT C –
Form of 5.701% Fixed-to-Floating Rate Senior Note due 2037

 i

 THIRTY-SEVENTH SUPPLEMENTAL INDENTURE

 THIRTY-SEVENTH SUPPLEMENTAL INDENTURE (this “ Thirty-Seventh Supplemental Indenture ”), dated as of June 5, 2026,
between SANTANDER HOLDINGS USA, INC., a corporation duly organized and existing under the laws of the Commonwealth of Virginia (the “ Company ”), having its principal office at 75 State Street, Boston, Massachusetts 02109, and
Deutsche Bank Trust Company Americas, a New York banking corporation, having a corporate trust office c/o Trust and Agency Services, 1 Columbus Circle, 4th Floor, Mail Stop: NYC01-0417, New York, NY 10019, as Trustee (the
“ Trustee ”).
 RECITALS OF THE COMPANY

 WHEREAS , the Company and the Trustee executed and delivered an Indenture, dated as of April 19, 2011 (the “ Base
Indenture ”) to provide for the issuance by the Company from time to time of its unsecured debentures, notes or other evidences of indebtedness (the “ Securities ”);

 WHEREAS , the Company amended the Base Indenture pursuant to the Eighth Supplemental Indenture, dated as of March 1, 2017, between
the Company and the Trustee (the “ Eighth Supplemental Indenture ,” and the Base Indenture, as amended by the Eighth Supplemental Indenture and as supplemented by this Thirty-Seventh Supplemental Indenture, the
“ Indenture ”);
 WHEREAS , Sections 2.01, 3.01 and 9.01 of the Base Indenture provide that the Company, when
authorized by a Board Resolution, and the Trustee, at any time and from time to time, may enter into one or more indentures supplemental to the Indenture, without the consent of any Holders, to, among other things, establish the terms of Securities
of any series as permitted by the Indenture;
 WHEREAS , the issuance and sale of (i) $1,000,000,000 aggregate principal amount of a
new series of the Securities of the Company designated as its 5.040% Fixed-to-Floating Rate Senior Notes due 2030 (the “ 2030 Notes ”), (ii)
$750,000,000 aggregate principal amount of a new series of the Securities of the Company designated as its 5.220% Fixed-to-Floating Rate Senior Notes due 2032 (the
“ 2032 Notes ”) and (iii) $750,000,000 aggregate principal amount of a new series of the Securities of the Company designated as its 5.701%
 Fixed-to-Floating Rate Senior Notes due 2037 (the “ 2037 Notes ” and, together with the 2030 Notes and the 2032 Notes, the “ Notes ”)
have been authorized by resolutions adopted by the board of directors of the Company;
 WHEREAS , the Company desires to issue and
sell the Notes as of the date hereof;
 WHEREAS , the Company desires to establish the terms of the Notes;

 WHEREAS , all things necessary to make this Thirty-Seventh Supplemental Indenture a legal and binding supplement to the Base Indenture
in accordance with its terms and the terms of the Base Indenture have been done;
 WHEREAS , the Company has complied with all
conditions precedent provided for in the Base Indenture relating to this Thirty-Seventh Supplemental Indenture; and

 WHEREAS , the Company has requested that the Trustee execute and deliver this
Thirty-Seventh Supplemental Indenture.
 NOW, THEREFORE:

 For and in consideration of the premises stated herein and the purchase of the Notes by the Holders thereof, the Company and the Trustee
covenant and agree, for the equal and proportionate benefit of the Holders of the Notes, as follows:
 ARTICLE 1

 SCOPE OF THIRTY-SEVENTH SUPPLEMENTAL INDENTURE

 Section 1.01 Scope . This Thirty-Seventh Supplemental Indenture constitutes a supplement to the Base Indenture and an integral part
of the Indenture and shall be read together with the Base Indenture and Eighth Supplemental Indenture as though all the provisions thereof are contained in one instrument. Except as expressly amended by the Eighth Supplemental Indenture and
Thirty-Seventh Supplemental Indenture, the terms and provisions of the Base Indenture shall remain in full force and effect. Notwithstanding the foregoing, this Thirty-Seventh Supplemental Indenture shall only apply to the Notes.

 ARTICLE 2
 DEFINITIONS

 Section 2.01 Definitions and Other Provisions of General Application . For all purposes of this Thirty-Seventh Supplemental
Indenture unless otherwise specified herein:
 (a) all terms used in this Thirty-Seventh Supplemental Indenture which are not otherwise
defined herein shall have the meanings they are given in the Base Indenture, as amended by the Eighth Supplemental Indenture;
 (b) the
provisions of general application stated in Sections 1.02 through 1.15 of the Base Indenture shall apply to this Thirty-Seventh Supplemental Indenture, except that the words “ herein ,” “ hereof ,”
“ hereto ” and “ hereunder ” and other words of similar import refer to this Thirty-Seventh Supplemental Indenture as a whole and not to the Base Indenture or any particular Article, Section or other subdivision of
the Base Indenture or this Thirty-Seventh Supplemental Indenture and the phrases “in writing” or “written” as used herein shall be deemed to include PDFs, e-mails and other electronic
means of transmission, unless otherwise indicated;
 (c) Section 1.01 of the Base Indenture is amended and supplemented, solely with respect
to the 2030 Notes, by inserting the following additional defined terms in their appropriate alphabetical positions:
 “ 2030 Fixed
Rate Period ” means from (and including) the Issue date to (but excluding) June 5, 2029.
 “ 2030 Fixed Rate Period
Interest Payment Date ” means semi-annually in arrears each June 5 and December 5, commencing on December 5, 2026, and ending on June 5, 2029.

 2

 “ 2030 Floating Rate Interest Period ” means the period beginning on (and
including) a 2030 Floating Rate Period Interest Payment Date and ending on (but excluding) the next succeeding 2030 Floating Rate Period Interest Payment Date during the Floating Rate Period; provided that the first Floating Rate Interest Period
will begin on (and include) June 5, 2029 and will end on (but exclude) the first 2030 Floating Rate Period Interest Payment Date.

 “ 2030 Floating Rate Period ” means from (and including) June 5, 2029 to (but excluding) the 2030 Maturity Date.

 “ 2030 Floating Rate Period Interest Payment Date ” means quarterly in arrears on September 5, 2029,
December 5, 2029, March 5, 2030 and the 2030 Maturity Date.
 “ 2030 Interest Determination Date ” means
the second U.S. Government Securities Business Day preceding the applicable 2030 Floating Rate Period Interest Payment Date.

 “ Business Day ” means any day, other than a Saturday or Sunday, that is neither a legal holiday nor a day on which banking
institutions in the City of New York are authorized or required by law, regulation or executive order to close.
 “ Issue
Date ” means June 5, 2026.
 (d) Section 1.01 of the Base Indenture is amended and supplemented, solely with respect to the
2032 Notes, by inserting the following additional defined terms in their appropriate alphabetical positions:
 “ 2032 Fixed Rate
Period ” means from (and including) the Issue date to (but excluding) June 5, 2031.
 “ 2032 Fixed Rate Period
Interest Payment Date ” means semi-annually in arrears each June 5 and December 5, commencing on December 5, 2026, and ending on June 5, 2031.

 “ 2032 Floating Rate Interest Period ” means the period beginning on (and including) a 2032 Floating Rate Period Interest
Payment Date and ending on (but excluding) the next succeeding 2032 Floating Rate Period Interest Payment Date during the Floating Rate Period; provided that the first Floating Rate Interest Period will begin on (and include) June 5, 2031 and
will end on (but exclude) the first 2032 Floating Rate Period Interest Payment Date.
 “ 2032 Floating Rate Period ” means
from (and including) June 5, 2031 to (but excluding) the 2032 Maturity Date.
 “ 2032 Floating Rate Period Interest
Payment Date ” means quarterly in arrears on September 5, 2031, December 5, 2031, March 5, 2032 and the 2032 Maturity Date.

 “ 2032 Interest Determination Date ” means the second U.S. Government Securities Business Day preceding the applicable
2032 Floating Rate Period Interest Payment Date.

 3

 “ Business Day ” means any day, other than a Saturday or Sunday, that is
neither a legal holiday nor a day on which banking institutions in the City of New York are authorized or required by law, regulation or executive order to close.

 “ Issue Date ” means June 5, 2026.

 (e) Section 1.01 of the Base Indenture is amended and supplemented, solely with respect to the 2037 Notes, by inserting the following
additional defined terms in their appropriate alphabetical positions:
 “ 2037 Fixed Rate Period ” means from (and
including) the Issue date to (but excluding) June 5, 2036.
 “ 2037 Fixed Rate Period Interest Payment Date ” means
semi-annually in arrears each June 5 and June 5, commencing on June 5, 2026, and ending on June 5, 2036.

 “ 2037 Floating Rate Interest Period ” means the period beginning on (and including) a 2037 Floating Rate Period Interest
Payment Date and ending on (but excluding) the next succeeding 2037 Floating Rate Period Interest Payment Date during the 2037 Floating Rate Period; provided that the first 2037 Floating Rate Interest Period will begin on (and include) June 5,
2036 and will end on (but exclude) the first 2037 Floating Rate Period Interest Payment Date.
 “ 2037 Floating Rate
Period ” means from (and including) June 5, 2036 to (but excluding) the 2037 Maturity Date.
 “ 2037 Floating Rate
Period Interest Payment Date ” means quarterly in arrears on September 5, 2036, December 5, 2036, March 5, 2037 and the 2037 Maturity Date.

 “ 2037 Interest Determination Date ” means the second U.S. Government Securities Business Day preceding the applicable 2037
Floating Rate Period Interest Payment Date.
 “ Business Day ” means any day, other than a Saturday or Sunday, that is
neither a legal holiday nor a day on which banking institutions in the City of New York are authorized or required by law, regulation or executive order to close.

 “ Issue Date ” means June 5, 2026.

 (f) Section 2.02 of the Base Indenture is amended and supplemented, solely with respect to the Notes, by revising the second to last paragraph
of the “Form of Face of Security” to read in its entirety as follows:
 Unless the certificate of authentication hereon has been
executed by the Trustee referred to on the reverse hereof by manual or electronic signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.

 4

 ARTICLE 3

 FORM AND TERMS OF THE 2030 NOTES

 Section 3.01 Form and Dating .

 (a) The 2030 Notes and the Certificate of Authentication shall be substantially in the form of Exhibit A attached hereto. The 2030 Notes
may have notations, a legend or legends or endorsements as may be required to comply with any law or with any rules of any securities exchange or usage. Each 2030 Note shall be dated the date of its authentication.

 (b) The terms contained in the 2030 Notes shall constitute, and are hereby expressly made, a part of the Indenture as supplemented by this
Thirty-Seventh Supplemental Indenture and the Company and the Trustee, by their execution and delivery of this Thirty-Seventh Supplemental Indenture, expressly agree to such terms and provisions and to be bound thereby.

 Section 3.02 Terms of the Notes . The following terms relating to the 2030 Notes are hereby established:

 (a) Title . The 2030 Notes shall constitute a series of Securities having the title “Santander Holdings USA, Inc. 5.040% Fixed-to-Floating Rate Senior Notes due 2030,” and the CUSIP number shall be “80282K BS4.”

 (b) Principal Amount . The aggregate principal amount of the 2030 Notes that may be authenticated and delivered under the Indenture, as
amended hereby, shall be $1,000,000,000 on the Issue Date. Provided that no Covenant Breach or Event of Default has occurred and is continuing with respect to the 2030 Notes, the Company may, without notice to or the consent of the Holders, create
and issue additional Securities having the same terms as, and ranking equally and ratably with, the 2030 Notes in all respects and so that such additional 2030 Notes will be consolidated and form a single series with, and have the same terms as to
status, redemption or otherwise as, the 2030 Notes initially issued.
 (c) Person to Whom Interest is Payable . Interest payable, and
punctually paid or duly provided for, on any 2030 Interest Payment Date will be paid to the Person in whose name the 2030 Notes are registered at the close of business on the Regular Record Date for such interest, which shall be the close of
business fifteen (15) calendar days (whether or not a Business Day) immediately preceding a 2030 Fixed Rate Period Interest Payment Date or a 2030 Floating Rate Period Interest Payment Date (together, the “ 2030 Interest Payment
Dates ” and, each, a “ 2030 Interest Payment Date ”). Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the
Person in whose name this Note is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of the 2030 Notes of this series not less
than 10 days prior to such Special Record Date, or be paid at any time in any other lawful manner and as provided for in the Base Indenture.

 5

 (d) Maturity Date . The entire outstanding principal of the 2030 Notes shall be
payable on June 5, 2030 (the “ 2030 Maturity Date ”). If the 2030 Maturity Date or the date of any repayment of the 2030 Notes falling within the 2030 Fixed Rate Period is not a Business Day, interest and principal shall be
payable on the next succeeding Business Day, but interest on that payment shall not accrue during the period from and after the 2030 Maturity Date.

 (e) Interest .

 (1) With respect to the 2030 Fixed Rate Period, the rate at which the 2030 Notes shall bear interest shall be 5.040% per annum
(the “ 2030 Initial Interest Rate ”). Interest will be calculated on the basis of twelve 30-day months or, in the case of an incomplete month, the actual number of days elapsed, in each
case assuming a 360-day year.
 (2) During the 2030 Floating Rate Period, the rate
at which the 2030 Notes shall bear interest shall be equal to the Benchmark (as defined below) plus 1.104% per annum (the “ 2030 Margin ”). Interest will be calculated on the basis of the actual number of days in each 2030 Floating
Rate Interest Period, assuming a 360-day year. In no event will the interest payable on the 2030 Notes be less than zero.

 (3) In the event that any scheduled 2030 Interest Payment Date (other than the 2030 Maturity Date) for the 2030 Notes falls on
a day that is not a Business Day, then payment of interest payable on such 2030 Interest Payment Date shall be postponed to the next succeeding Business Day (and no interest on such payment will accrue for the period from and after such scheduled
2030 Interest Payment Date); provided that, during the 2030 Floating Rate Period, if that Business Day falls in the next succeeding calendar month, such 2030 Floating Rate Period Interest Payment Date will be the immediately preceding Business Day.
If any such 2030 Floating Rate Period Interest Payment Date (other than the 2030 Maturity Date) is postponed or brought forward as described above, the payment of interest due on such postponed or brought forward 2030 Floating Rate Period Interest
Payment Date will include interest accrued to but excluding such postponed or brought forward 2030 Floating Rate Period Interest Payment Date.

 (4) If a Redemption Date or repayment of the 2030 Notes falls within the 2030 Floating Rate Period but does not occur on a 2030
Floating Rate Period Interest Payment Date, (i) the related 2030 Interest Determination Date shall be deemed to be the date that is two U.S. Government Securities Business Days prior to such Redemption Date or repayment, (ii) the related
Observation Period shall be deemed to end on (but exclude) the related 2030 Interest Determination Date for such Redemption Date or repayment, (iii) the 2030 Floating Rate Period will be deemed to be shortened accordingly and
(iv) corresponding adjustments will be deemed to be made to the Compounded SOFR Index Rate formula.
 (f) Calculation of Benchmark;
Definitions . For the purposes of this Section 3.02, capitalized terms used but not otherwise defined in this section shall have the following meanings:

 (1) “ Benchmark ” means, initially, the Compounded SOFR Index Rate; provided that if a Benchmark Transition
Event and related Benchmark Replacement Date have occurred with respect to SOFR or the then-current Benchmark, then “Benchmark” means the applicable Benchmark Replacement.

 6

 (2) “ Benchmark Replacement ” means the first alternative
set forth in the order below that shall be determined by the Company or its designee (in consultation with the Company) as of the Benchmark Replacement Date:

 a. the sum of: (a) the alternate rate of interest that has been selected or recommended by the Relevant Governmental Body
as the replacement for the then-current Benchmark for the applicable Corresponding Tenor (if any) and (b) the Benchmark Replacement Adjustment;

 b. the sum of: (a) the ISDA Fallback Rate and (b) the Benchmark Replacement Adjustment; and

 c. the sum of: (a) the alternate rate of interest that has been selected by the Company or its designee (in consultation
with the Company) as the replacement for the then-current Benchmark for the applicable Corresponding Tenor giving due consideration to any industry-accepted rate of interest as a replacement for the then-current Benchmark for U.S. dollar-denominated
floating rate notes at such time and (b) the Benchmark Replacement Adjustment.
 (3) “ Benchmark Replacement
Adjustment ” means the first alternative set forth in the order below that can be determined by the Company or its designee (in consultation with the Company) as of the Benchmark Replacement Date:

 a. the spread adjustment (which may be a positive or negative value or zero) that has been (i) selected or recommended by
the Relevant Governmental Body or (ii) determined by the Company or its designee (in consultation with the Company) in accordance with the method for calculating or determining such spread adjustment that has been selected or recommended by the
Relevant Governmental Body, in each case for the applicable Unadjusted Benchmark Replacement;
 b. if the applicable
Unadjusted Benchmark Replacement is equivalent to the ISDA Fallback Rate, then the ISDA Fallback Adjustment; or
 c. the
spread adjustment (which may be a positive or negative value or zero) that has been selected by the Company or its designee (in consultation with the Company) giving due consideration to industry-accepted spread adjustments (if any), or method for
calculating or determining such spread adjustment, for the replacement of the then-current Benchmark with the applicable Unadjusted Benchmark Replacement for U.S. dollar-denominated floating rate notes at such time.

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 (4) “ Benchmark Replacement Date ” means the earliest to
occur of the following events with respect to the then-current Benchmark (including any daily published component used in the calculation thereof):

 a. in the case of clause (a) or (b) of the definition of “Benchmark Transition Event,” the later of
(i) the date of the public statement or publication of information referenced therein and (ii) the date on which the administrator of the Benchmark permanently or indefinitely ceases to provide the Benchmark (or such component); or

 b. in the case of clause (c) of the definition of “Benchmark Transition Event,” the date of the public
statement or publication of information referenced therein.
 For the avoidance of doubt, if the event giving rise to the Benchmark
Replacement Date occurs on the same day as, but earlier than, the Reference Time in respect of any determination, the Benchmark Replacement Date will be deemed to have occurred prior to the Reference Time for such determination.

 (5) “ Benchmark Transition Event ” means the occurrence of one or more of the following events with respect to
the then-current Benchmark (including any daily published component used in the calculation thereof):
 a. a public
statement or publication of information by or on behalf of the administrator of the Benchmark (or such component) announcing that such administrator has ceased or will cease to provide the Benchmark (or such component), permanently or indefinitely,
provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the Benchmark (or such component);

 b. a public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark (or
such component), the central bank for the currency of the Benchmark (or such component), an insolvency official with jurisdiction over the administrator for the Benchmark (or such component), a resolution authority with jurisdiction over the
administrator for the Benchmark (or such component) or a court or an entity with similar insolvency or resolution authority over the administrator for the Benchmark (or such component), which states that the administrator of the Benchmark (or such
component) has ceased or will cease to provide the Benchmark (or such component) permanently or indefinitely, provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the
Benchmark (or such component); or

 8

 c. a public statement or publication of information by the regulatory
supervisor for the administrator of the Benchmark announcing that the Benchmark is no longer representative.
 (6)
“ Compounded SOFR Index Rate ” means, in relation to a Floating Rate Interest Period, the rate computed by the calculation agent in accordance with the following formula (and the resulting percentage will be rounded if necessary to
the nearest seventh decimal place, with 0.00000005 being rounded upwards):

 Where:

 “d” is the number of calendar days from (and including) SOFR Index Start to
(but excluding) SOFR Index End (being the number of calendar days in the Observation Period);

 “ SOFR Index Start ” is the SOFR Index value for the day which
is two U.S. Government Securities Business Days preceding the first date of the relevant 2030 Floating Rate Interest Period; and

 “ SOFR Index End ” is the SOFR Index value for the day which is
two U.S. Government Securities Business Days preceding the 2030 Floating Rate Period Interest Payment Date relating to such 2030 Floating Rate Interest Period;

 (7) “ Corresponding Tenor ” with respect to a Benchmark Replacement means a tenor (including overnight) having
approximately the same length (disregarding Business Day adjustments) as the applicable tenor for the then-current Benchmark.

 (8) “ designee ” means an affiliate or any other agent of the Company.

 (9) “ ISDA Fallback Rate ” means the rate that would apply for derivatives transactions referencing the ISDA
Definitions to be effective upon the occurrence of an index cessation date with respect to the Benchmark for the applicable tenor excluding the applicable ISDA Fallback Adjustment.

 (10) “ ISDA Definitions ” means the 2006 ISDA Definitions published by the International Swaps and Derivatives
Association, Inc. (“ ISDA ”) or any successor thereto, as amended or supplemented from time to time, or any successor definitional booklet for interest rate derivatives published from time to time.

 (11) “ ISDA Fallback Adjustment ” means the spread adjustment (which may be a positive or negative value or
zero) that would apply for derivatives transactions referencing the ISDA.

 9

 (12) “ NY Federal Reserve’s website ” means the
website of the Federal Reserve Bank of New York (the “NY Federal Reserve”), currently at http://www.newyorkfed.org, or any successor website of the NY Federal Reserve or the website of any successor administrator of the Secured Overnight
Financing Rate.
 (13) “ Observation Period ” means, in respect of each 2030 Floating Rate Interest Period,
the period from (and including) the day falling two U.S. Government Securities Business Days prior to the first day of the relevant Floating Rate Interest Period to (but excluding) the day falling two U.S. Government Securities Business Days prior
to the relevant 2030 Floating Rate Period Interest Payment Date for such 2030 Floating Rate Interest Period.
 (14)
“ Reference Time ” means (1) if the Benchmark is Compounded SOFR Index Rate, the SOFR Determination Time, and (2) if the Benchmark is not Compounded SOFR Index Rate, the time determined by the Company or its designee (in
consultation with the Company) in accordance with the Benchmark Replacement Conforming Changes.
 (15) “ Relevant
Governmental Body ” means the Federal Reserve and/or the NY Federal Reserve, or a committee officially endorsed or convened by the Federal Reserve and/or the NY Federal Reserve or any successor thereto.

 (16) “ Relevant Rules ” means, at any time, the laws, regulations, requirements, guidelines and policies
relating to capital adequacy (including, without limitation, as to leverage, total loss-absorbing capacity, or regulatory long-term debt requirements) then in effect in the United States and applicable to the Company from time to time and any
regulations, requirements, guidelines and policies relating to capital adequacy adopted from time to time (whether or not such requirements, guidelines or policies are applied generally or specifically to the Company or to the Company and any of its
holding or subsidiary companies or any subsidiary of any such holding company).
 (17) “ SOFR ” means, with
respect to any U.S. Government Securities Business Day, the rate determined by the calculation agent in accordance with the following provisions:

 a. the Secured Overnight Financing Rate published for such U.S. Government Securities Business Day as such rate appears on the
NY Federal Reserve’s website on the immediately following U.S. Government Securities Business Day at the SOFR Determination Time.

 b. if the rate does not so appear, the Secured Overnight Financing Rate published on the NY Federal Reserve’s website
for the first preceding U.S. Government Securities Business Day for which the Secured Overnight Financing Rate was published on the NY Federal Reserve’s website.

 (18) “ SOFR Administrator ” means the Federal Reserve Bank of New York (or a successor administrator of SOFR).

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 (19) “ SOFR Administrator’s Website ” means the
website of the Federal Reserve Bank of New York, currently at http://www.newyorkfed.org, or any successor source.
 (20)
“ SOFR Determination Time ” means, with respect to any U.S. Government Securities Business Day, 3:00 p.m. (New York City time) on such U.S. Government Securities Business Day.

 (21) “ SOFR Index ” means, with respect to any U.S. Government Securities Business Day:

 a. the SOFR Index value as published by the SOFR Administrator as such index appears on the SOFR Administrator’s Website
at the SOFR Determination Time; provided that
 b. if a SOFR Index value does not so appear as specified in (a) above
at the SOFR Determination Time, then (i) if a Benchmark Transition Event and its related Benchmark Replacement Date have not occurred with respect to SOFR, then Compounded SOFR Index Rate shall be the rate determined pursuant to
Section 3.02(g) or (ii) if a Benchmark Transition Event and its related Benchmark Replacement Date have occurred in respect of SOFR, then Compounded SOFR Index Rate shall be the rate determined pursuant to Section 3.02(h).

 (22) “ Unadjusted Benchmark Replacement ” means the Benchmark Replacement excluding the Benchmark Replacement
Adjustment.
 (23) “ U.S. Government Securities Business Day ” means any day except for a Saturday, Sunday
or a day on which the Securities Industry and Financial Markets Association recommends that the fixed income departments of its members be closed for the entire day for purposes of trading in U.S. government securities.

 Notwithstanding clauses (a) and (b) of the definition of “SOFR” above, if the Company or its designee (in consultation with
the Company) determines on or prior to the relevant 2030 Interest Determination Date that a Benchmark Transition Event and related Benchmark Replacement Date have occurred with respect to SOFR, then the “Benchmark Transition Provisions”
set forth below will thereafter apply to all determinations of the rate of interest payable on the 2030 Notes during the 2030 Floating Rate Period.

 In accordance with and subject to the Benchmark Transition Provisions, after a Benchmark Transition Event and related Benchmark Replacement
Date have occurred, the amount of interest that will be payable for each interest period on the 2030 Notes during the 2030 Floating Rate Period will be determined by reference to a rate per annum equal to the Benchmark Replacement plus the Margin.

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 (g) SOFR Index Unavailability . If SOFR Index Start or SOFR Index End is not published on the relevant 2030 Interest Determination Date and a Benchmark Transition Event and its related
Benchmark Replacement Date have not occurred with respect to SOFR, “ Compounded SOFR Index Rate ” shall mean, for the relevant interest period for which such index is not available, the rate of return on a daily compounded interest
investment calculated in accordance with the formula for SOFR Averages, and definitions required for such formula, published on the SOFR Administrator’s Website at https://www.newyorkfed.org/markets/treasury-repo-reference-rates-information
(or such successor website). For the purposes of this provision, references in the SOFR Averages compounding formula and related definitions to “calculation period” shall be replaced with “Observation Period” and the words
“that is, 30-, 90-, or 180- calendar days” shall be removed. If the daily SOFR (“ SOFRi ”) does not
so appear for any day, “i” in the Observation Period, SOFRi for such day “i” shall be SOFR published in respect of the first preceding U.S. Government Securities Business Day for which SOFR was published on the SOFR
Administrator’s Website.
 (h) Benchmark Transition .

 (1) If the Company or its designee (in consultation with the Company) determine that a Benchmark Transition Event and related
Benchmark Replacement Date have occurred prior to the applicable Reference Time in respect of any determination of the Benchmark on any date, the applicable Benchmark Replacement shall replace the then-current Benchmark for all purposes relating to
the 2030 Notes during the 2030 Floating Rate Period in respect of such determination on such date and all determinations on all subsequent dates; provided that, if the Company or its designee (in consultation with the Company) are unable to or do
not determine a Benchmark Replacement in accordance with this Section 3.02 prior to 5:00 p.m. (New York City time) on the relevant 2030 Interest Determination Date, the interest rate for the related 2030 Floating Rate Interest Period shall be
equal to the interest rate in effect for the immediately preceding 2030 Floating Rate Interest Period or, in the case of the 2030 Interest Determination Date prior to the first 2030 Floating Rate Period Interest Payment Date, the 2030 Initial
Interest Rate.
 (2) In connection with the implementation of a Benchmark Replacement, the Company or its designee (in
consultation with the Company) shall have the right to make changes to (1) any 2030 Interest Determination Date, 2030 Floating Rate Period Interest Payment Date, Reference Time, business day convention or 2030 Floating Rate Interest Period,
(2) the manner, timing and frequency of determining the rate and amounts of interest that are payable on the 2030 Notes during the 2030 Floating Rate Period and the conventions relating to such determination and calculations with respect to
interest, (3) rounding conventions, (4) tenors and (5) any other terms or provisions of the 2030 Notes during the 2030 Floating Rate Period, in each case that the Company or its designee (in consultation with the Company) determines,
from time to time, to be appropriate to reflect the determination and implementation of such Benchmark Replacement in a manner substantially consistent with market practice (or, if the Company or its designee (in consultation with the Company)
decides that implementation of any portion of such market practice is not administratively feasible or determine that no market practice for use of the Benchmark Replacement exists, in such other manner as the Company or its designee (in
consultation with the Company) determines is appropriate (acting in good faith)) (the “ Benchmark Replacement Conforming Changes ”). Any Benchmark Replacement Conforming Changes will apply to the 2030 Notes for all future
2030 Floating Rate Interest Periods.

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 (3) The Company shall promptly give notice of the determination of the
Benchmark Replacement, the Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes to the Trustee, the paying agent, the calculation agent and the Holders of the 2030 Notes; provided that failure to provide such notice will
have no impact on the effectiveness of, or otherwise invalidate, any such determination.
 (4) All determinations,
decisions, elections and any calculations made by the Company or its designee for the purposes of determining the Benchmark Replacement, the Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes will be conclusive and
binding on the Holders of the 2030 Notes, the Company, the calculation agent, the Trustee and the paying agent, absent manifest error. If made by the Company’s designee, such determinations, decisions, elections and calculations will be made
after consulting with the Company, and its designees will not make any such determination, decision, election or calculation to which the Company objects. Notwithstanding anything to the contrary in this Thirty-Seventh Supplemental Indenture or the
2030 Notes, any determinations, decisions, calculations or elections made in accordance with this Section 3.02(h) shall become effective without consent from the Holders of the 2030 Notes or any other party.

 (5) Any determination, decision or election relating to the Benchmark will be made by the Company on the basis described above.
The calculation agent shall have no liability for not making any such determination, decision or election. In addition, the Company may designate an entity (which may be an affiliate of the Company) to make any determination, decision or election
that the Company has the right to make in connection with the determination of the Benchmark.
 (6) Notwithstanding any
other provision set forth herein, no Benchmark Replacement shall be adopted, nor shall the applicable Benchmark Replacement Adjustment be applied, nor shall any Benchmark Replacement Conforming Changes be made, if in the Company’s
determination, the same could reasonably be expected to prejudice the qualification of the 2030 Notes as eligible liabilities or loss absorbing capacity instruments for the purposes of the Relevant Rules.

 (7) By its acquisition of the 2030 Notes, each Holder of the 2030 Notes (including each Holder of a beneficial interest in the
2030 Notes) (i) acknowledges, accepts, consents and agrees to be bound by the Company’s or its designee’s determination of a Benchmark Transition Event, a Benchmark Replacement Date, the Benchmark Replacement, the Benchmark
Replacement Adjustment and any Benchmark Replacement Conforming Changes, including as may occur without any prior notice from the Company and without the need for the Company to obtain any further consent from such Holder of the 2030 Notes,
(ii) shall waive any and all claims, in law and/or in equity, against the Trustee, the paying agent and the calculation agent or the Company’s designee for, agree not to initiate a suit against the Trustee, the paying agent and the

 13

calculation agent or the Company’s designee in respect of, and agree that none of the Trustee, the paying agent or the calculation agent or the Company’s designee shall be liable for,
the determination of or the Company’s failure or delay to determine any Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming
Changes, and any losses suffered in connection therewith and (iii) shall agree that none of the Trustee, the paying agent or the calculation agent or the Company’s designee shall have any obligation to determine, confirm or verify any
Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes (including any adjustments thereto), including in the event of any failure
or delay by the Company to determine any Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes.

 (8) Except as set forth herein, all percentages resulting from any calculation of any interest rate for the 2030 Notes shall be
rounded, if necessary, to the nearest one hundred thousandth of a percentage point, with five one-millionths of a percentage point rounded upward (e.g., 9.876545% (or .09876545) would be rounded to 9.87655%
(or .0987655)), and all dollar amounts shall be rounded to the nearest cent, with one-half cent being rounded upward.

 (i) Place of Payment of Principal and Interest . Payment of the principal of (and premium, if any) and interest on the 2030 Notes will be
made at the office or agency of the Company maintained for that purpose in New York, New York, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts against
surrender of any Note in the case of any payment due at the 2030 Maturity Date; provided , however , that (i) if any Note is a Global Security, payments shall be made in respect of such Note pursuant to the Applicable Procedures of
the Depositary as in effect from time to time, and (ii) if any Note is not a Global Security, payment of interest in respect of such Note will be made by check mailed to the address of the Person entitled thereto as such address shall appear in
the Security Register at the close of business on the Regular Record Date for such interest. Notwithstanding the foregoing, if any Note is not a Global Security and has a principal amount of at least $1,000,000, upon request, the Company will pay
any amount that becomes due on such Note by wire transfer of immediately available funds to an account at a bank in New York City, on the due date. To request such a wire payment, the Holder of such Note must give the Paying Agent appropriate wire
transfer instructions at least five Business Days before the requested wire payment is due. In the case of any interest payment due on a 2030 Interest Payment Date, the instructions must be given by the person or entity who is the Holder on the
relevant Regular Record Date. Any wire instructions, once properly given, will remain in effect unless and until new instructions are given in the manner described above.

 14

 (j) Optional Redemption .

 (1) On or after December 2, 2026 (180 days after the Issue Date) (or, if additional 2030 Notes are issued, beginning 180
days after the Issue Date of such additional 2030 Notes), and prior to the 2030 First Par Call Date, the Company may redeem the 2030 Notes at its option, in whole or in part, at any time and from time to time, at a Redemption Price (expressed as a
percentage of principal amount and rounded to three decimal places), equal to the greater of:
 a. (i) The sum of the
present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the 2030 Notes matured on the 2030 First Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 15 basis points less (ii) interest accrued to the date of redemption, and

 b. 100% of the principal amount of the 2030 Notes to be redeemed,

 plus in either case, accrued and unpaid interest thereon to the redemption date.

 (2) On the 2030 First Par Call Date, the Company may redeem the 2030 Notes, in whole but not in part, or on or after
May 5, 2030 (which is the date that is one month prior to the 2030 Maturity Date), in whole or in part, at any time and from time to time, in each case at a redemption price equal to 100% of the principal amount of the 2030 Notes being redeemed
plus accrued and unpaid interest thereon to the redemption date.
 In the case of a partial redemption, selection of the 2030 Notes for
redemption will be made pro rata, by lot or by such other method as required by the rules of DTC. No 2030 Notes of a principal amount of $2,000 or less will be redeemed in part. If any Note is to be redeemed in part only, the notice of redemption
that relates to the Note will state the portion of the principal amount of the note to be redeemed. A new Note in a principal amount equal to the unredeemed portion of the Note will be issued in the name of the Holder of the note upon surrender for
cancellation of the original Note. For so long as the 2030 Notes are held by DTC (or another depositary), the redemption of the 2030 Notes shall be done in accordance with the policies and procedures of the depositary.

 Unless the Company defaults in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the 2030
Notes or portions thereof called for redemption.
 Neither the Trustee nor the calculation agent shall be responsible for or have any
responsibility to determine or make any calculations in connection with any redemption.
 Notice of any redemption will be mailed or
electronically delivered at least 10 days but not more than 60 days before the redemption date to each Holder of the 2030 Notes to be redeemed, and at least fifteen days before the redemption date to the Trustee.

 (3) Solely for the purposes of this Section 3.02(j), the following terms shall have the following meanings:

 15

 a. “ 2030 First Par Call Date ” means June 5, 2029
(one year prior to the 2030 Maturity Date).
 b. “ Treasury Rate ” means, with respect to any redemption
date, the yield determined by the Company in accordance with the following two paragraphs:
 The Treasury Rate shall be determined by the
Company after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third Business Day preceding the redemption date based upon the
yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as “Selected Interest Rates
(Daily)—H.15” (or any successor designation or publication) (“H.15”) under the caption “U.S. government securities—Treasury constant maturities—Nominal” (or any successor caption or heading)
(“H.15 TCM”). In determining the Treasury Rate, the Company shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the 2030 First Par Call Date
(the “Remaining Life”); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter
than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the 2030 First Par Call Date on a straight-line basis (using the actual number of days) using such
yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the
Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant
maturity from the redemption date.
 If on the third Business Day preceding the redemption date H.15 TCM is no longer published, the
Company shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second Business Day preceding such redemption date of the United States Treasury
security maturing on, or with a maturity that is closest to, the 2030 First Par Call Date, as applicable. If there is no United States Treasury security maturing on the 2030 First Par Call Date but there are two or more United States Treasury
securities with a maturity date equally distant from the 2030 First Par Call Date, one with a maturity date preceding the 2030 First Par Call Date and one with a maturity date following the 2030 First Par Call Date,

 16

the Company shall select the United States Treasury security with a maturity date preceding the 2030 First Par Call Date. If there are two or more United States Treasury securities maturing on
the 2030 First Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Company shall select from among these two or more United States Treasury securities the United States Treasury security
that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the
semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States
Treasury security, and rounded to three decimal places. The Company’s actions and determinations in determining the redemption price shall be conclusive and binding for all purposes, absent manifest error.

 (4) If the Redemption Date is not a Business Day, interest and principal shall be payable on the next succeeding Business Day,
but interest on that payment shall not accrue during the period from and after the Redemption Date.
 (k) Sinking Fund . There shall
be no sinking fund for the 2030 Notes.
 (l) Denomination . The 2030 Notes shall be in minimum denominations of $2,000 and integral
multiples of $1,000 in excess thereof.
 (m) Currency of the Notes . The 2030 Notes shall be denominated, and payment of
principal and interest of the 2030 Notes shall be payable in, the currency of the United States of America.
 (n) Currency of
Payment . The principal of and interest on the 2030 Notes shall be payable in the currency of the United States of America.
 (o)
 Defeasance . Article 13 of the Base Indenture shall apply to the 2030 Notes.
 (p) Registered Form . The 2030 Notes shall
be issuable as registered Global Securities, and the depositary for the 2030 Notes shall be The Depository Trust Company, New York, New York (“ DTC ”) or any successor depositary appointed by the Company within 90 days of the
termination of services of DTC (or any successor to DTC). Sections 2.04 and 3.05 of the Base Indenture shall apply to the 2030 Notes.
 (q)
 Covenants . The covenants set forth in Article 10 of the Base Indenture shall apply to the 2030 Notes.
 (r) Additional Terms .
Other terms applicable to the 2030 Notes are as otherwise provided for below.

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 ARTICLE 4

 FORM AND TERMS OF THE 2032 NOTES

 Section 4.01 Form and Dating .

 (a) The 2032 Notes and the Certificate of Authentication shall be substantially in the form of Exhibit A attached hereto. The 2032 Notes
may have notations, a legend or legends or endorsements as may be required to comply with any law or with any rules of any securities exchange or usage. Each 2032 Note shall be dated the date of its authentication.

 (b) The terms contained in the 2032 Notes shall constitute, and are hereby expressly made, a part of the Indenture as supplemented by this
Thirty-Seventh Supplemental Indenture and the Company and the Trustee, by their execution and delivery of this Thirty-Seventh Supplemental Indenture, expressly agree to such terms and provisions and to be bound thereby.

 Section 4.02 Terms of the Notes . The following terms relating to the 2032 Notes are hereby established:

 (a) Title . The 2032 Notes shall constitute a series of Securities having the title “Santander Holdings USA, Inc. 5.220% Fixed-to-Floating Rate Senior Notes due 2032,” and the CUSIP number shall be “80282K BT2.”

 (b) Principal Amount . The aggregate principal amount of the 2032 Notes that may be authenticated and delivered under the Indenture, as
amended hereby, shall be $750,000,000 on the Issue Date. Provided that no Covenant Breach or Event of Default has occurred and is continuing with respect to the 2032 Notes, the Company may, without notice to or the consent of the Holders, create and
issue additional Securities having the same terms as, and ranking equally and ratably with, the 2032 Notes in all respects and so that such additional 2032 Notes will be consolidated and form a single series with, and have the same terms as to
status, redemption or otherwise as, the 2032 Notes initially issued.
 (c) Person to Whom Interest is Payable . Interest payable, and
punctually paid or duly provided for, on any 2032 Interest Payment Date will be paid to the Person in whose name the 2032 Notes are registered at the close of business on the Regular Record Date for such interest, which shall be the close of
business fifteen (15) calendar days (whether or not a Business Day) immediately preceding a 2032 Fixed Rate Period Interest Payment Date or a 2032 Floating Rate Period Interest Payment Date (together, the “ 2032 Interest Payment
Dates ” and, each, a “ 2032 Interest Payment Date ”). Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the
Person in whose name this Note is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of the 2032 Notes of this series not less
than 10 days prior to such Special Record Date, or be paid at any time in any other lawful manner and as provided for in the Base Indenture.

 (d) Maturity Date . The entire outstanding principal of the 2032 Notes shall be payable on June 5, 2032 (the “ 2032 Maturity
Date ”). If the 2032 Maturity Date or the date of any repayment of the 2032 Notes falling within the 2032 Fixed Rate Period is not a Business Day, interest and principal shall be payable on the next succeeding Business Day, but interest on
that payment shall not accrue during the period from and after the 2032 Maturity Date.

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 (e) Interest .

 (1) With respect to the 2032 Fixed Rate Period, the rate at which the 2032 Notes shall bear interest shall be 5.220% per annum
(the “ 2032 Initial Interest Rate ”). Interest will be calculated on the basis of twelve 30-day months or, in the case of an incomplete month, the actual number of days elapsed, in each
case assuming a 360-day year.
 (2) During the 2032 Floating Rate Period, the rate
at which the 2032 Notes shall bear interest shall be equal to the Benchmark (as defined below) plus 1.276% per annum (the “ 2032 Margin ”). Interest will be calculated on the basis of the actual number of days in each 2032 Floating
Rate Interest Period, assuming a 360-day year. In no event will the interest payable on the 2032 Notes be less than zero.

 (3) In the event that any scheduled 2032 Interest Payment Date (other than the 2032 Maturity Date) for the 2032 Notes falls on
a day that is not a Business Day, then payment of interest payable on such 2032 Interest Payment Date shall be postponed to the next succeeding Business Day (and no interest on such payment will accrue for the period from and after such scheduled
2032 Interest Payment Date); provided that, during the 2032 Floating Rate Period, if that Business Day falls in the next succeeding calendar month, such 2032 Floating Rate Period Interest Payment Date will be the immediately preceding Business Day.
If any such 2032 Floating Rate Period Interest Payment Date (other than the 2032 Maturity Date) is postponed or brought forward as described above, the payment of interest due on such postponed or brought forward 2032 Floating Rate Period Interest
Payment Date will include interest accrued to but excluding such postponed or brought forward 2032 Floating Rate Period Interest Payment Date.

 (4) If a Redemption Date or repayment of the 2032 Notes falls within the 2032 Floating Rate Period but does not occur on a 2032
Floating Rate Period Interest Payment Date, (i) the related 2032 Interest Determination Date shall be deemed to be the date that is two U.S. Government Securities Business Days prior to such Redemption Date or repayment, (ii) the related
Observation Period shall be deemed to end on (but exclude) the related 2032 Interest Determination Date for such Redemption Date or repayment, (iii) the 2032 Floating Rate Period will be deemed to be shortened accordingly and
(iv) corresponding adjustments will be deemed to be made to the Compounded SOFR Index Rate formula.
 (f) Calculation of Benchmark;
Definitions . For the purposes of this Section 3.02, capitalized terms used but not otherwise defined in this section shall have the following meanings:

 19

 (1) “ Benchmark ” means, initially, the Compounded SOFR
Index Rate; provided that if a Benchmark Transition Event and related Benchmark Replacement Date have occurred with respect to SOFR or the then-current Benchmark, then “Benchmark” means the applicable Benchmark Replacement.

 (2) “ Benchmark Replacement ” means the first alternative set forth in the order below that shall be
determined by the Company or its designee (in consultation with the Company) as of the Benchmark Replacement Date:
 a. the
sum of: (a) the alternate rate of interest that has been selected or recommended by the Relevant Governmental Body as the replacement for the then-current Benchmark for the applicable Corresponding Tenor (if any) and (b) the Benchmark
Replacement Adjustment;
 b. the sum of: (a) the ISDA Fallback Rate and (b) the Benchmark Replacement Adjustment;
and
 c. the sum of: (a) the alternate rate of interest that has been selected by the Company or its designee (in
consultation with the Company) as the replacement for the then-current Benchmark for the applicable Corresponding Tenor giving due consideration to any industry-accepted rate of interest as a replacement for the then-current Benchmark for U.S.
dollar-denominated floating rate notes at such time and (b) the Benchmark Replacement Adjustment.
 (3)
“ Benchmark Replacement Adjustment ” means the first alternative set forth in the order below that can be determined by the Company or its designee (in consultation with the Company) as of the Benchmark Replacement Date:

 a. the spread adjustment (which may be a positive or negative value or zero) that has been (i) selected or recommended by
the Relevant Governmental Body or (ii) determined by the Company or its designee (in consultation with the Company) in accordance with the method for calculating or determining such spread adjustment that has been selected or recommended by the
Relevant Governmental Body, in each case for the applicable Unadjusted Benchmark Replacement;
 b. if the applicable
Unadjusted Benchmark Replacement is equivalent to the ISDA Fallback Rate, then the ISDA Fallback Adjustment; or
 c. the
spread adjustment (which may be a positive or negative value or zero) that has been selected by the Company or its designee (in consultation with the Company) giving due consideration to industry-accepted spread adjustments (if any), or method for
calculating or determining such spread adjustment, for the replacement of the then-current Benchmark with the applicable Unadjusted Benchmark Replacement for U.S. dollar-denominated floating rate notes at such time.

 20

 (4) “ Benchmark Replacement Date ” means the earliest to
occur of the following events with respect to the then-current Benchmark (including any daily published component used in the calculation thereof):

 a. in the case of clause (a) or (b) of the definition of “Benchmark Transition Event,” the later of
(i) the date of the public statement or publication of information referenced therein and (ii) the date on which the administrator of the Benchmark permanently or indefinitely ceases to provide the Benchmark (or such component); or

 b. in the case of clause (c) of the definition of “Benchmark Transition Event,” the date of the public
statement or publication of information referenced therein.
 For the avoidance of doubt, if the event giving rise to the Benchmark
Replacement Date occurs on the same day as, but earlier than, the Reference Time in respect of any determination, the Benchmark Replacement Date will be deemed to have occurred prior to the Reference Time for such determination.

 (5) “ Benchmark Transition Event ” means the occurrence of one or more of the following events with respect to
the then-current Benchmark (including any daily published component used in the calculation thereof):
 a. a public
statement or publication of information by or on behalf of the administrator of the Benchmark (or such component) announcing that such administrator has ceased or will cease to provide the Benchmark (or such component), permanently or indefinitely,
provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the Benchmark (or such component);

 b. a public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark (or
such component), the central bank for the currency of the Benchmark (or such component), an insolvency official with jurisdiction over the administrator for the Benchmark (or such component), a resolution authority with jurisdiction over the
administrator for the Benchmark (or such component) or a court or an entity with similar insolvency or resolution authority over the administrator for the Benchmark (or such component), which states that the administrator of the Benchmark (or such
component) has ceased or will cease to provide the Benchmark (or such component) permanently or indefinitely, provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the
Benchmark (or such component); or

 21

 c. a public statement or publication of information by the regulatory
supervisor for the administrator of the Benchmark announcing that the Benchmark is no longer representative.
 (6)
“ Compounded SOFR Index Rate ” means, in relation to a Floating Rate Interest Period, the rate computed by the calculation agent in accordance with the following formula (and the resulting percentage will be rounded if necessary to
the nearest seventh decimal place, with 0.00000005 being rounded upwards):

 Where:

 “d” is the number of calendar days from (and including) SOFR Index Start to
(but excluding) SOFR Index End (being the number of calendar days in the Observation Period);

 “ SOFR Index Start ” is the SOFR Index value for the day which
is two U.S. Government Securities Business Days preceding the first date of the relevant 2032 Floating Rate Interest Period; and

 “ SOFR Index End ” is the SOFR Index value for the day which is
two U.S. Government Securities Business Days preceding the 2032 Floating Rate Period Interest Payment Date relating to such 2032 Floating Rate Interest Period;

 (7) “ Corresponding Tenor ” with respect to a Benchmark Replacement means a tenor (including overnight) having
approximately the same length (disregarding Business Day adjustments) as the applicable tenor for the then-current Benchmark.

 (8) “ designee ” means an affiliate or any other agent of the Company.

 (9) “ ISDA Fallback Rate ” means the rate that would apply for derivatives transactions referencing the ISDA
Definitions to be effective upon the occurrence of an index cessation date with respect to the Benchmark for the applicable tenor excluding the applicable ISDA Fallback Adjustment.

 (10) “ ISDA Definitions ” means the 2006 ISDA Definitions published by the International Swaps and Derivatives
Association, Inc. (“ ISDA ”) or any successor thereto, as amended or supplemented from time to time, or any successor definitional booklet for interest rate derivatives published from time to time.

 (11) “ ISDA Fallback Adjustment ” means the spread adjustment (which may be a positive or negative value or
zero) that would apply for derivatives transactions referencing the ISDA.

 22

 (12) “ NY Federal Reserve’s website ” means the
website of the Federal Reserve Bank of New York (the “NY Federal Reserve”), currently at http://www.newyorkfed.org, or any successor website of the NY Federal Reserve or the website of any successor administrator of the Secured Overnight
Financing Rate.
 (13) “ Observation Period ” means, in respect of each 2032 Floating Rate Interest Period,
the period from (and including) the day falling two U.S. Government Securities Business Days prior to the first day of the relevant Floating Rate Interest Period to (but excluding) the day falling two U.S. Government Securities Business Days prior
to the relevant 2032 Floating Rate Period Interest Payment Date for such 2032 Floating Rate Interest Period.
 (14)
“ Reference Time ” means (1) if the Benchmark is Compounded SOFR Index Rate, the SOFR Determination Time, and (2) if the Benchmark is not Compounded SOFR Index Rate, the time determined by the Company or its designee (in
consultation with the Company) in accordance with the Benchmark Replacement Conforming Changes.
 (15) “ Relevant
Governmental Body ” means the Federal Reserve and/or the NY Federal Reserve, or a committee officially endorsed or convened by the Federal Reserve and/or the NY Federal Reserve or any successor thereto.

 (16) “ Relevant Rules ” means, at any time, the laws, regulations, requirements, guidelines and policies
relating to capital adequacy (including, without limitation, as to leverage, total loss-absorbing capacity, or regulatory long-term debt requirements) then in effect in the United States and applicable to the Company from time to time and any
regulations, requirements, guidelines and policies relating to capital adequacy adopted from time to time (whether or not such requirements, guidelines or policies are applied generally or specifically to the Company or to the Company and any of its
holding or subsidiary companies or any subsidiary of any such holding company).
 (17) “ SOFR ” means, with
respect to any U.S. Government Securities Business Day, the rate determined by the calculation agent in accordance with the following provisions:

 a. the Secured Overnight Financing Rate published for such U.S. Government Securities Business Day as such rate appears on the
NY Federal Reserve’s website on the immediately following U.S. Government Securities Business Day at the SOFR Determination Time.

 b. if the rate does not so appear, the Secured Overnight Financing Rate published on the NY Federal Reserve’s website
for the first preceding U.S. Government Securities Business Day for which the Secured Overnight Financing Rate was published on the NY Federal Reserve’s website.

 (18) “ SOFR Administrator ” means the Federal Reserve Bank of New York (or a successor administrator of SOFR).

 23

 (19) “ SOFR Administrator’s Website ” means the
website of the Federal Reserve Bank of New York, currently at http://www.newyorkfed.org, or any successor source.
 (20)
“ SOFR Determination Time ” means, with respect to any U.S. Government Securities Business Day, 3:00 p.m. (New York City time) on such U.S. Government Securities Business Day.

 (21) “ SOFR Index ” means, with respect to any U.S. Government Securities Business Day:

 a. the SOFR Index value as published by the SOFR Administrator as such index appears on the SOFR Administrator’s Website
at the SOFR Determination Time; provided that
 b. if a SOFR Index value does not so appear as specified in (a) above
at the SOFR Determination Time, then (i) if a Benchmark Transition Event and its related Benchmark Replacement Date have not occurred with respect to SOFR, then Compounded SOFR Index Rate shall be the rate determined pursuant to
Section 3.02(g) or (ii) if a Benchmark Transition Event and its related Benchmark Replacement Date have occurred in respect of SOFR, then Compounded SOFR Index Rate shall be the rate determined pursuant to Section 3.02(h).

 (22) “ Unadjusted Benchmark Replacement ” means the Benchmark Replacement excluding the Benchmark Replacement
Adjustment.
 (23) “ U.S. Government Securities Business Day ” means any day except for a Saturday, Sunday
or a day on which the Securities Industry and Financial Markets Association recommends that the fixed income departments of its members be closed for the entire day for purposes of trading in U.S. government securities.

 Notwithstanding clauses (a) and (b) of the definition of “SOFR” above, if the Company or its designee (in consultation with
the Company) determines on or prior to the relevant 2032 Interest Determination Date that a Benchmark Transition Event and related Benchmark Replacement Date have occurred with respect to SOFR, then the “Benchmark Transition Provisions”
set forth below will thereafter apply to all determinations of the rate of interest payable on the 2032 Notes during the 2032 Floating Rate Period.

 In accordance with and subject to the Benchmark Transition Provisions, after a Benchmark Transition Event and related Benchmark Replacement
Date have occurred, the amount of interest that will be payable for each interest period on the 2032 Notes during the 2032 Floating Rate Period will be determined by reference to a rate per annum equal to the Benchmark Replacement plus the Margin.

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 (g) SOFR Index Unavailability . If SOFR Index Start or SOFR Index End is not published on the relevant 2032 Interest Determination Date and a Benchmark Transition Event and its related
Benchmark Replacement Date have not occurred with respect to SOFR, “ Compounded SOFR Index Rate ” shall mean, for the relevant interest period for which such index is not available, the rate of return on a daily compounded interest
investment calculated in accordance with the formula for SOFR Averages, and definitions required for such formula, published on the SOFR Administrator’s Website at https://www.newyorkfed.org/markets/treasury-repo-reference-rates-information
(or such successor website). For the purposes of this provision, references in the SOFR Averages compounding formula and related definitions to “calculation period” shall be replaced with “Observation Period” and the words
“that is, 30-, 90-, or 180- calendar days” shall be removed. If the daily SOFR (“ SOFRi ”) does not
so appear for any day, “i” in the Observation Period, SOFRi for such day “i” shall be SOFR published in respect of the first preceding U.S. Government Securities Business Day for which SOFR was published on the SOFR
Administrator’s Website.
 (h) Benchmark Transition .

 (1) If the Company or its designee (in consultation with the Company) determine that a Benchmark Transition Event and related
Benchmark Replacement Date have occurred prior to the applicable Reference Time in respect of any determination of the Benchmark on any date, the applicable Benchmark Replacement shall replace the then-current Benchmark for all purposes relating to
the 2032 Notes during the 2032 Floating Rate Period in respect of such determination on such date and all determinations on all subsequent dates; provided that, if the Company or its designee (in consultation with the Company) are unable to or do
not determine a Benchmark Replacement in accordance with this Section 3.02 prior to 5:00 p.m. (New York City time) on the relevant 2032 Interest Determination Date, the interest rate for the related 2032 Floating Rate Interest Period shall be
equal to the interest rate in effect for the immediately preceding 2032 Floating Rate Interest Period or, in the case of the 2032 Interest Determination Date prior to the first 2032 Floating Rate Period Interest Payment Date, the 2032 Initial
Interest Rate.
 (2) In connection with the implementation of a Benchmark Replacement, the Company or its designee (in
consultation with the Company) shall have the right to make changes to (1) any 2032 Interest Determination Date, 2032 Floating Rate Period Interest Payment Date, Reference Time, business day convention or 2032 Floating Rate Interest Period,
(2) the manner, timing and frequency of determining the rate and amounts of interest that are payable on the 2032 Notes during the 2032 Floating Rate Period and the conventions relating to such determination and calculations with respect to
interest, (3) rounding conventions, (4) tenors and (5) any other terms or provisions of the 2032 Notes during the 2032 Floating Rate Period, in each case that the Company or its designee (in consultation with the Company) determines,
from time to time, to be appropriate to reflect the determination and implementation of such Benchmark Replacement in a manner substantially consistent with market practice (or, if the Company or its designee (in consultation with the Company)
decides that implementation of any portion of such market practice is not administratively feasible or determine that no market practice for use of the Benchmark Replacement exists, in such other manner as the Company or its designee (in
consultation with the Company) determines is appropriate (acting in good faith)) (the “ Benchmark Replacement Conforming Changes ”). Any Benchmark Replacement Conforming Changes will apply to the 2032 Notes for all future
2032 Floating Rate Interest Periods.

 25

 (3) The Company shall promptly give notice of the determination of the
Benchmark Replacement, the Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes to the Trustee, the paying agent, the calculation agent and the Holders of the 2032 Notes; provided that failure to provide such notice will
have no impact on the effectiveness of, or otherwise invalidate, any such determination.
 (4) All determinations,
decisions, elections and any calculations made by the Company or its designee for the purposes of determining the Benchmark Replacement, the Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes will be conclusive and
binding on the Holders of the 2032 Notes, the Company, the calculation agent, the Trustee and the paying agent, absent manifest error. If made by the Company’s designee, such determinations, decisions, elections and calculations will be made
after consulting with the Company, and its designees will not make any such determination, decision, election or calculation to which the Company objects. Notwithstanding anything to the contrary in this Thirty-Seventh Supplemental Indenture or the
2032 Notes, any determinations, decisions, calculations or elections made in accordance with this Section 3.02(h) shall become effective without consent from the Holders of the 2032 Notes or any other party.

 (5) Any determination, decision or election relating to the Benchmark will be made by the Company on the basis described above.
The calculation agent shall have no liability for not making any such determination, decision or election. In addition, the Company may designate an entity (which may be an affiliate of the Company) to make any determination, decision or election
that the Company has the right to make in connection with the determination of the Benchmark.
 (6) Notwithstanding any
other provision set forth herein, no Benchmark Replacement shall be adopted, nor shall the applicable Benchmark Replacement Adjustment be applied, nor shall any Benchmark Replacement Conforming Changes be made, if in the Company’s
determination, the same could reasonably be expected to prejudice the qualification of the 2032 Notes as eligible liabilities or loss absorbing capacity instruments for the purposes of the Relevant Rules.

 (7) By its acquisition of the 2032 Notes, each Holder of the 2032 Notes (including each Holder of a beneficial interest in the
2032 Notes) (i) acknowledges, accepts, consents and agrees to be bound by the Company’s or its designee’s determination of a Benchmark Transition Event, a Benchmark Replacement Date, the Benchmark Replacement, the Benchmark
Replacement Adjustment and any Benchmark Replacement Conforming Changes, including as may occur without any prior notice from the Company and without the need for the Company to obtain any further consent from such Holder of the 2032 Notes,
(ii) shall waive any and all claims, in law and/or in equity, against the Trustee, the paying agent and the calculation agent or the Company’s designee for, agree not to initiate a suit against the Trustee, the paying agent and the

 26

calculation agent or the Company’s designee in respect of, and agree that none of the Trustee, the paying agent or the calculation agent or the Company’s designee shall be liable for,
the determination of or the Company’s failure or delay to determine any Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming
Changes, and any losses suffered in connection therewith and (iii) shall agree that none of the Trustee, the paying agent or the calculation agent or the Company’s designee shall have any obligation to determine, confirm or verify any
Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes (including any adjustments thereto), including in the event of any failure
or delay by the Company to determine any Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes.

 (8) Except as set forth herein, all percentages resulting from any calculation of any interest rate for the 2032 Notes shall be
rounded, if necessary, to the nearest one hundred thousandth of a percentage point, with five one-millionths of a percentage point rounded upward (e.g., 9.876545% (or .09876545) would be rounded to 9.87655%
(or .0987655)), and all dollar amounts shall be rounded to the nearest cent, with one-half cent being rounded upward.

 (i) Place of Payment of Principal and Interest . Payment of the principal of (and premium, if any) and interest on the 2032 Notes will be
made at the office or agency of the Company maintained for that purpose in New York, New York, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts against
surrender of any Note in the case of any payment due at the 2032 Maturity Date; provided , however , that (i) if any Note is a Global Security, payments shall be made in respect of such Note pursuant to the Applicable Procedures of
the Depositary as in effect from time to time, and (ii) if any Note is not a Global Security, payment of interest in respect of such Note will be made by check mailed to the address of the Person entitled thereto as such address shall appear in
the Security Register at the close of business on the Regular Record Date for such interest. Notwithstanding the foregoing, if any Note is not a Global Security and has a principal amount of at least $1,000,000, upon request, the Company will pay
any amount that becomes due on such Note by wire transfer of immediately available funds to an account at a bank in New York City, on the due date. To request such a wire payment, the Holder of such Note must give the Paying Agent appropriate wire
transfer instructions at least five Business Days before the requested wire payment is due. In the case of any interest payment due on a 2032 Interest Payment Date, the instructions must be given by the person or entity who is the Holder on the
relevant Regular Record Date. Any wire instructions, once properly given, will remain in effect unless and until new instructions are given in the manner described above.

 27

 (j) Optional Redemption .

 (1) On or after December 2, 2026 (180 days after the Issue Date) (or, if additional 2032 Notes are issued, beginning 180
days after the Issue Date of such additional 2032 Notes), and prior to the 2032 First Par Call Date, the Company may redeem the 2032 Notes at its option, in whole or in part, at any time and from time to time, at a Redemption Price (expressed as a
percentage of principal amount and rounded to three decimal places), equal to the greater of:
 a. (i) The sum of the
present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the 2032 Notes matured on the 2032 First Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 20 basis points less (ii) interest accrued to the date of redemption, and

 b. 100% of the principal amount of the 2032 Notes to be redeemed,

 plus in either case, accrued and unpaid interest thereon to the redemption date.

 (2) On the 2032 First Par Call Date, the Company may redeem the 2032 Notes, in whole but not in part, or on or after
May 5, 2032 (which is the date that is one month prior to the 2032 Maturity Date), in whole or in part, at any time and from time to time, in each case at a redemption price equal to 100% of the principal amount of the 2032 Notes being redeemed
plus accrued and unpaid interest thereon to the redemption date.
 In the case of a partial redemption, selection of the 2032 Notes for
redemption will be made pro rata, by lot or by such other method as required by the rules of DTC. No 2032 Notes of a principal amount of $2,000 or less will be redeemed in part. If any Note is to be redeemed in part only, the notice of redemption
that relates to the Note will state the portion of the principal amount of the note to be redeemed. A new Note in a principal amount equal to the unredeemed portion of the Note will be issued in the name of the Holder of the note upon surrender for
cancellation of the original Note. For so long as the 2032 Notes are held by DTC (or another depositary), the redemption of the 2032 Notes shall be done in accordance with the policies and procedures of the depositary.

 Unless the Company defaults in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the 2032
Notes or portions thereof called for redemption.
 Neither the Trustee nor the calculation agent shall be responsible for or have any
responsibility to determine or make any calculations in connection with any redemption.
 Notice of any redemption will be mailed or
electronically delivered at least 10 days but not more than 60 days before the redemption date to each Holder of the 2032 Notes to be redeemed, and at least fifteen days before the redemption date to the Trustee.

 (3) Solely for the purposes of this Section 3.02(j), the following terms shall have the following meanings:

 28

 a. “ 2032 First Par Call Date ” means June 5, 2031
(one year prior to the 2032 Maturity Date).
 b. “ Treasury Rate ” means, with respect to any redemption
date, the yield determined by the Company in accordance with the following two paragraphs:
 The Treasury Rate shall be determined by the
Company after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third Business Day preceding the redemption date based upon the
yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as “Selected Interest Rates
(Daily)—H.15” (or any successor designation or publication) (“H.15”) under the caption “U.S. government securities—Treasury constant maturities—Nominal” (or any successor caption or heading)
(“H.15 TCM”). In determining the Treasury Rate, the Company shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the 2032 First Par Call Date
(the “Remaining Life”); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter
than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the 2032 First Par Call Date on a straight-line basis (using the actual number of days) using such
yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the
Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant
maturity from the redemption date.
 If on the third Business Day preceding the redemption date H.15 TCM is no longer published, the
Company shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second Business Day preceding such redemption date of the United States Treasury
security maturing on, or with a maturity that is closest to, the 2032 First Par Call Date, as applicable. If there is no United States Treasury security maturing on the 2032 First Par Call Date but there are two or more United States Treasury
securities with a maturity date equally distant from the 2032 First Par Call Date, one with a maturity date preceding the 2032 First Par Call Date and one with a maturity date following the 2032 First Par Call Date,

 29

the Company shall select the United States Treasury security with a maturity date preceding the 2032 First Par Call Date. If there are two or more United States Treasury securities maturing on
the 2032 First Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Company shall select from among these two or more United States Treasury securities the United States Treasury security
that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the
semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States
Treasury security, and rounded to three decimal places. The Company’s actions and determinations in determining the redemption price shall be conclusive and binding for all purposes, absent manifest error.

 (4) If the Redemption Date is not a Business Day, interest and principal shall be payable on the next succeeding Business Day,
but interest on that payment shall not accrue during the period from and after the Redemption Date.
 (k) Sinking Fund . There shall
be no sinking fund for the 2032 Notes.
 (l) Denomination . The 2032 Notes shall be in minimum denominations of $2,000 and integral
multiples of $1,000 in excess thereof.
 (m) Currency of the Notes . The 2032 Notes shall be denominated, and payment of
principal and interest of the 2032 Notes shall be payable in, the currency of the United States of America.
 (n) Currency of
Payment . The principal of and interest on the 2032 Notes shall be payable in the currency of the United States of America.
 (o)
 Defeasance . Article 13 of the Base Indenture shall apply to the 2032 Notes.
 (p) Registered Form . The 2032 Notes shall
be issuable as registered Global Securities, and the depositary for the 2032 Notes shall be The Depository Trust Company, New York, New York (“ DTC ”) or any successor depositary appointed by the Company within 90 days of the
termination of services of DTC (or any successor to DTC). Sections 2.04 and 3.05 of the Base Indenture shall apply to the 2032 Notes.
 (q)
 Covenants . The covenants set forth in Article 10 of the Base Indenture shall apply to the 2032 Notes.
 (r) Additional Terms .
Other terms applicable to the 2032 Notes are as otherwise provided for below.

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 ARTICLE 5

 FORM AND TERMS OF THE 2037 NOTES

 Section 5.01 Form and Dating .

 (a) The 2037 Notes and the Certificate of Authentication shall be substantially in the form of Exhibit C attached hereto. The 2037 Notes
may have notations, a legend or legends or endorsements as may be required to comply with any law or with any rules of any securities exchange or usage. Each 2037 Note shall be dated the date of its authentication.

 (b) The terms contained in the 2037 Notes shall constitute, and are hereby expressly made, a part of the Indenture as supplemented by this
Thirty-Seventh Supplemental Indenture and the Company and the Trustee, by their execution and delivery of this Thirty-Seventh Supplemental Indenture, expressly agree to such terms and provisions and to be bound thereby.

 Section 5.02 Terms of the Notes . The following terms relating to the 2037 Notes are hereby established:

 (a) Title . The 2037 Notes shall constitute a series of Securities having the title

 “Santander Holdings USA, Inc. 5.701% Fixed-to-Floating Rate Senior Notes
due 2037,” and the CUSIP number shall be “80282K BU9.”
 (b) Principal Amount . The aggregate principal amount of
the 2037 Notes that may be authenticated and delivered under the Indenture, as amended hereby, shall be $750,000,000 on the Issue Date. Provided that no Covenant Breach or Event of Default has occurred and is continuing with respect to the 2037
Notes, the Company may, without notice to or the consent of the Holders, create and issue additional Securities having the same terms as, and ranking equally and ratably with, the 2037 Notes in all respects and so that such additional 2037 Notes
will be consolidated and form a single series with, and have the same terms as to status, redemption or otherwise as, the 2037 Notes initially issued.

 (c) Person to Whom Interest is Payable . Interest payable, and punctually paid or duly provided for, on any 2037 Interest Payment Date
will be paid to the Person in whose name the 2037 Notes are registered at the close of business on the Regular Record Date for such interest, which shall be the close of business fifteen (15) calendar days (whether or not a Business Day)
immediately preceding a 2037 Fixed Rate Period Interest Payment Date or a 2037 Floating Rate Period Interest Payment Date (together, the “ 2037 Interest Payment Dates ” and, each, a “ 2037 Interest Payment Date ”).
Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Note is registered at the close of business on a
Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of the 2037 Notes of this series not less than 10 days prior to such Special Record Date, or be paid at any time in
any other lawful manner and as provided for in the Base Indenture.

 31

 (d) Maturity Date . The entire outstanding principal of the 2037 Notes shall be
payable on June 5, 2037 (the “ 2037 Maturity Date ”). If the 2037 Maturity Date or the date of any repayment of the 2037 Notes falling within the 2037 Fixed Rate Period is not a Business Day, interest and principal shall be
payable on the next succeeding Business Day, but interest on that payment shall not accrue during the period from and after the 2037 Maturity Date.

 (e) Interest .

 (1) With respect to the 2037 Fixed Rate Period, the rate at which the 2037 Notes shall bear interest shall be 5.701% per annum
(the “ 2037 Initial Interest Rate ”). Interest will be calculated on the basis of twelve 30-day months or, in the case of an incomplete month, the actual number of days elapsed, in each case
assuming a 360-day year.
 (2) During the 2037 Floating Rate Period, the rate at
which the 2037 Notes shall bear interest shall be equal to the Benchmark (as defined below) plus 1.596% per annum (the “ 2037 Margin ”). Interest will be calculated on the basis of the actual number of days in each 2037 Floating
Rate Interest Period, assuming a 360-day year. In no event will the interest payable on the 2037 Notes be less than zero.

 (3) In the event that any scheduled 2037 Interest Payment Date (other than the 2037 Maturity Date) for the 2037 Notes falls on
a day that is not a Business Day, then payment of interest payable on such 2037 Interest Payment Date shall be postponed to the next succeeding Business Day (and no interest on such payment will accrue for the period from and after such scheduled
2037 Interest Payment Date); provided that, during the 2037 Floating Rate Period, if that Business Day falls in the next succeeding calendar month, such 2037 Floating Rate Period Interest Payment Date will be the immediately preceding Business Day.
If any such 2037 Floating Rate Period Interest Payment Date (other than the 2037 Maturity Date) is postponed or brought forward as described above, the payment of interest due on such postponed or brought forward 2037 Floating Rate Period Interest
Payment Date will include interest accrued to but excluding such postponed or brought forward 2037 Floating Rate Period Interest Payment Date.

 (4) If a Redemption Date or repayment of the 2037 Notes falls within the 2037 Floating Rate Period but does not occur on a 2037
Floating Rate Period Interest Payment Date, (i) the related 2037 Interest Determination Date shall be deemed to be the date that is two U.S. Government Securities Business Days prior to such Redemption Date or repayment, (ii) the related
Observation Period shall be deemed to end on (but exclude) the related 2037 Interest Determination Date for such Redemption Date or repayment, (iii) the 2037 Floating Rate Period will be deemed to be shortened accordingly and
(iv) corresponding adjustments will be deemed to be made to the Compounded SOFR Index Rate formula.
 (f) Calculation of Benchmark;
Definitions . For the purposes of this Section 3.02, capitalized terms used but not otherwise defined in this section shall have the following meanings:

 32

 (1) “ Benchmark ” means, initially, the Compounded SOFR
Index Rate; provided that if a Benchmark Transition Event and related Benchmark Replacement Date have occurred with respect to SOFR or the then-current Benchmark, then “Benchmark” means the applicable Benchmark Replacement.

 (2) “ Benchmark Replacement ” means the first alternative set forth in the order below that shall be
determined by the Company or its designee (in consultation with the Company) as of the Benchmark Replacement Date:
 a. the
sum of: (a) the alternate rate of interest that has been selected or recommended by the Relevant Governmental Body as the replacement for the then-current Benchmark for the applicable Corresponding Tenor (if any) and (b) the Benchmark
Replacement Adjustment;
 b. the sum of: (a) the ISDA Fallback Rate and (b) the Benchmark Replacement Adjustment;
and
 c. the sum of: (a) the alternate rate of interest that has been selected by the Company or its designee (in
consultation with the Company) as the replacement for the then-current Benchmark for the applicable Corresponding Tenor giving due consideration to any industry-accepted rate of interest as a replacement for the then-current Benchmark for U.S.
dollar-denominated floating rate notes at such time and (b) the Benchmark Replacement Adjustment.
 (3)
“ Benchmark Replacement Adjustment ” means the first alternative set forth in the order below that can be determined by the Company or its designee (in consultation with the Company) as of the Benchmark Replacement Date:

 a. the spread adjustment (which may be a positive or negative value or zero) that has been (i) selected or recommended by
the Relevant Governmental Body or (ii) determined by the Company or its designee (in consultation with the Company) in accordance with the method for calculating or determining such spread adjustment that has been selected or recommended by the
Relevant Governmental Body, in each case for the applicable Unadjusted Benchmark Replacement;
 b. if the applicable
Unadjusted Benchmark Replacement is equivalent to the ISDA Fallback Rate, then the ISDA Fallback Adjustment; or
 c. the
spread adjustment (which may be a positive or negative value or zero) that has been selected by the Company or its designee (in consultation with the Company) giving due consideration to industry-accepted spread adjustments (if any), or method for
calculating or determining such spread adjustment, for the replacement of the then- current Benchmark with the applicable Unadjusted Benchmark Replacement for U.S. dollar-denominated floating rate notes at such time.

 33

 (4) “ Benchmark Replacement Date ” means the earliest to
occur of the following events with respect to the then-current Benchmark (including any daily published component used in the calculation thereof):

 a. in the case of clause (a) or (b) of the definition of “Benchmark Transition Event,” the later of
(i) the date of the public statement or publication of information referenced therein and (ii) the date on which the administrator of the Benchmark permanently or indefinitely ceases to provide the Benchmark (or such component); or

 b. in the case of clause (c) of the definition of “Benchmark Transition Event,” the date of the public
statement or publication of information referenced therein.
 For the avoidance of doubt, if the event giving rise to the Benchmark
Replacement Date occurs on the same day as, but earlier than, the Reference Time in respect of any determination, the Benchmark Replacement Date will be deemed to have occurred prior to the Reference Time for such determination.

 (5) “ Benchmark Transition Event ” means the occurrence of one or more of the following events with respect to
the then-current Benchmark (including any daily published component used in the calculation thereof):
 a. a public
statement or publication of information by or on behalf of the administrator of the Benchmark (or such component) announcing that such administrator has ceased or will cease to provide the Benchmark (or such component), permanently or indefinitely,
provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the Benchmark (or such component);

 b. a public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark (or
such component), the central bank for the currency of the Benchmark (or such component), an insolvency official with jurisdiction over the administrator for the Benchmark (or such component), a resolution authority with jurisdiction over the
administrator for the Benchmark (or such component) or a court or an entity with similar insolvency or resolution authority over the administrator for the Benchmark (or such component), which states that the administrator of the Benchmark (or such
component) has ceased or will cease to provide the Benchmark (or such component) permanently or indefinitely, provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the
Benchmark (or such component); or

 34

 c. a public statement or publication of information by the regulatory
supervisor for the administrator of the Benchmark announcing that the Benchmark is no longer representative.
 (6)
“ Compounded SOFR Index Rate ” means, in relation to a Floating Rate Interest Period, the rate computed by the calculation agent in accordance with the following formula (and the resulting percentage will be rounded if necessary to
the nearest seventh decimal place, with 0.00000005 being rounded upwards):

 Where:

 “d” is the number of calendar days from (and including) SOFR Index Start to
(but excluding) SOFR Index End (being the number of calendar days in the Observation Period);

 “ SOFR Index Start ” is the SOFR Index value for the day which
is two U.S. Government Securities Business Days preceding the first date of the relevant 2037 Floating Rate Interest Period; and

 “ SOFR Index End ” is the SOFR Index value for the day which is
two U.S. Government Securities Business Days preceding the 2037 Floating Rate Period Interest Payment Date relating to such 2037 Floating Rate Interest Period;

 (7) “ Corresponding Tenor ” with respect to a Benchmark Replacement means a tenor (including overnight) having
approximately the same length (disregarding Business Day adjustments) as the applicable tenor for the then-current Benchmark.

 (8) “ designee ” means an affiliate or any other agent of the Company.

 (9) “ ISDA Fallback Rate ” means the rate that would apply for derivatives transactions referencing the ISDA
Definitions to be effective upon the occurrence of an index cessation date with respect to the Benchmark for the applicable tenor excluding the applicable ISDA Fallback Adjustment.

 (10) “ ISDA Definitions ” means the 2006 ISDA Definitions published by the International Swaps and Derivatives
Association, Inc. (“ ISDA ”) or any successor thereto, as amended or supplemented from time to time, or any successor definitional booklet for interest rate derivatives published from time to time.

 (11) “ ISDA Fallback Adjustment ” means the spread adjustment (which may be a positive or negative value or
zero) that would apply for derivatives transactions referencing the ISDA.

 35

 (12) “ NY Federal Reserve’s website ” means the
website of the Federal Reserve Bank of New York (the “NY Federal Reserve”), currently at http://www.newyorkfed.org, or any successor website of the NY Federal Reserve or the website of any successor administrator of the Secured Overnight
Financing Rate.
 (13) “ Observation Period ” means, in respect of each 2037 Floating Rate Interest Period,
the period from (and including) the day falling two U.S. Government Securities Business Days prior to the first day of the relevant 2037 Floating Rate Interest Period to (but excluding) the day falling two U.S. Government Securities Business Days
prior to the relevant 2037 Floating Rate Period Interest Payment Date for such Floating Rate Interest Period.
 (14)
“ Reference Time ” means (1) if the Benchmark is Compounded SOFR Index Rate, the SOFR Determination Time, and (2) if the Benchmark is not Compounded SOFR Index Rate, the time determined by the Company or its designee (in
consultation with the Company) in accordance with the Benchmark Replacement Conforming Changes.
 (15) “ Relevant
Governmental Body ” means the Federal Reserve and/or the NY Federal Reserve, or a committee officially endorsed or convened by the Federal Reserve and/or the NY Federal Reserve or any successor thereto.

 (16) “ Relevant Rules ” means, at any time, the laws, regulations, requirements, guidelines and policies
relating to capital adequacy (including, without limitation, as to leverage, TLAC, or regulatory long-term debt requirements) then in effect in the United States and applicable to the Company from time to time and any regulations, requirements,
guidelines and policies relating to capital adequacy adopted from time to time (whether or not such requirements, guidelines or policies are applied generally or specifically to the Company or to the Company and any of its holding or subsidiary
companies or any subsidiary of any such holding company).
 (17) “ SOFR ” means, with respect to any U.S.
Government Securities Business Day, the rate determined by the calculation agent in accordance with the following provisions:

 a. the Secured Overnight Financing Rate published for such U.S. Government Securities Business Day as such rate appears on the
NY Federal Reserve’s website on the immediately following U.S. Government Securities Business Day at the SOFR Determination Time.

 b. if the rate does not so appear, the Secured Overnight Financing Rate published on the NY Federal Reserve’s website
for the first preceding U.S. Government Securities Business Day for which the Secured Overnight Financing Rate was published on the NY Federal Reserve’s website.

 (18) “ SOFR Administrator ” means the Federal Reserve Bank of New York (or a successor administrator of SOFR).

 36

 (19) “ SOFR Administrator’s Website ” means the
website of the Federal Reserve Bank of New York, currently at http://www.newyorkfed.org, or any successor source.
 (20)
“ SOFR Determination Time ” means, with respect to any U.S. Government Securities Business Day, 3:00 p.m. (New York City time) on such U.S. Government Securities Business Day.

 (21) “ SOFR Index ” means, with respect to any U.S. Government Securities Business Day:

 a. the SOFR Index value as published by the SOFR Administrator as such index appears on the SOFR Administrator’s Website
at the SOFR Determination Time; provided that
 b. if a SOFR Index value does not so appear as specified in (a) above
at the SOFR Determination Time, then (i) if a Benchmark Transition Event and its related Benchmark Replacement Date have not occurred with respect to SOFR, then Compounded SOFR Index Rate shall be the rate determined pursuant to
Section 3.02(g) or (ii) if a Benchmark Transition Event and its related Benchmark Replacement Date have occurred in respect of SOFR, then Compounded SOFR Index Rate shall be the rate determined pursuant to Section 3.02(h).

 (22) “ Unadjusted Benchmark Replacement ” means the Benchmark Replacement excluding the Benchmark Replacement
Adjustment.
 (23) “ U.S. Government Securities Business Day ” means any day except for a Saturday, Sunday
or a day on which the Securities Industry and Financial Markets Association recommends that the fixed income departments of its members be closed for the entire day for purposes of trading in U.S. government securities.

 Notwithstanding clauses (a) and (b) of the definition of “SOFR” above, if the Company or its designee (in consultation with
the Company) determines on or prior to the relevant 2037 Interest Determination Date that a Benchmark Transition Event and related Benchmark Replacement Date have occurred with respect to SOFR, then the “Benchmark Transition Provisions”
set forth below will thereafter apply to all determinations of the rate of interest payable on the 2037 Notes during the 2037 Floating Rate Period.

 In accordance with and subject to the Benchmark Transition Provisions, after a Benchmark Transition Event and related Benchmark Replacement
Date have occurred, the amount of interest that will be payable for each interest period on the 2037 Notes during the 2037 Floating Rate Period will be determined by reference to a rate per annum equal to the Benchmark Replacement plus the Margin.

 37

 (g) SOFR Index Unavailability . If SOFR Index Start or SOFR Index End is not published on the relevant 2037 Interest Determination Date and a Benchmark Transition Event and its related
Benchmark Replacement Date have not occurred with respect to SOFR, “ Compounded SOFR Index Rate ” shall mean, for the relevant interest period for which such index is not available, the rate of return on a daily compounded interest
investment calculated in accordance with the formula for SOFR Averages, and definitions required for such formula, published on the SOFR Administrator’s Website at https://www.newyorkfed.org/markets/treasury-repo-reference-rates-information
(or such successor website). For the purposes of this provision, references in the SOFR Averages compounding formula and related definitions to “calculation period” shall be replaced with “Observation Period” and the words
“that is, 30-, 90-, or 180- calendar days” shall be removed. If the daily SOFR (“ SOFRi ”) does not
so appear for any day, “i” in the Observation Period, SOFRi for such day “i” shall be SOFR published in respect of the first preceding U.S. Government Securities Business Day for which SOFR was published on the SOFR
Administrator’s Website.
 (h) Benchmark Transition .

 (1) If the Company or its designee (in consultation with the Company) determine that a Benchmark Transition Event and related
Benchmark Replacement Date have occurred prior to the applicable Reference Time in respect of any determination of the Benchmark on any date, the applicable Benchmark Replacement shall replace the then-current Benchmark for all purposes relating to
the 2037 Notes during the 2037 Floating Rate Period in respect of such determination on such date and all determinations on all subsequent dates; provided that, if the Company or its designee (in consultation with the Company) are unable to or do
not determine a Benchmark Replacement in accordance with this Section 3.02 prior to 5:00 p.m. (New York City time) on the relevant 2037 Interest Determination Date, the interest rate for the related 2037 Floating Rate Interest Period shall be
equal to the interest rate in effect for the immediately preceding 2037 Floating Rate Interest Period or, in the case of the 2037 Interest Determination Date prior to the first 2037 Floating Rate Period Interest Payment Date, the 2037 Initial
Interest Rate.
 (2) In connection with the implementation of a Benchmark Replacement, the Company or its designee (in
consultation with the Company) shall have the right to make changes to (1) any 2037 Interest Determination Date, 2037 Floating Rate Period Interest Payment Date, Reference Time, business day convention or 2037 Floating Rate Interest Period,
(2) the manner, timing and frequency of determining the rate and amounts of interest that are payable on the 2037 Notes during the 2037 Floating Rate Period and the conventions relating to such determination and calculations with respect to
interest, (3) rounding conventions, (4) tenors and (5) any other terms or provisions of the 2037 Notes during the 2037 Floating Rate Period, in each case that the Company or its designee (in consultation with the Company) determines,
from time to time, to be appropriate to reflect the determination and implementation of such Benchmark Replacement in a manner substantially consistent with market practice (or, if the Company or its designee (in consultation with the Company)
decides that implementation of any portion of such market practice is not administratively feasible or determine that no market practice for use of the Benchmark Replacement exists, in such other manner as the Company or its designee (in
consultation with the Company) determines is appropriate (acting in good faith)) (the “ Benchmark Replacement Conforming Changes ”). Any Benchmark Replacement Conforming Changes will apply to the 2037 Notes for all future
2037 Floating Rate Interest Periods.

 38

 (3) The Company shall promptly give notice of the determination of the
Benchmark Replacement, the Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes to the Trustee, the paying agent, the calculation agent and the Holders of the 2037 Notes; provided that failure to provide such notice will
have no impact on the effectiveness of, or otherwise invalidate, any such determination.
 (4) All determinations,
decisions, elections and any calculations made by the Company or its designee for the purposes of determining the Benchmark Replacement, the Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes will be conclusive and
binding on the Holders of the 2037 Notes, the Company, the calculation agent, the Trustee and the paying agent, absent manifest error. If made by the Company’s designee, such determinations, decisions, elections and calculations will be made
after consulting with the Company, and its designees will not make any such determination, decision, election or calculation to which the Company objects. Notwithstanding anything to the contrary in this Thirty-Seventh Supplemental Indenture or the
2037 Notes, any determinations, decisions, calculations or elections made in accordance with this Section 3.02(h) shall become effective without consent from the Holders of the 2037 Notes or any other party.

 (5) Any determination, decision or election relating to the Benchmark will be made by the Company on the basis described above.
The calculation agent shall have no liability for not making any such determination, decision or election. In addition, the Company may designate an entity (which may be an affiliate of the Company) to make any determination, decision or election
that the Company has the right to make in connection with the determination of the Benchmark.
 (6) Notwithstanding any
other provision set forth herein, no Benchmark Replacement shall be adopted, nor shall the applicable Benchmark Replacement Adjustment be applied, nor shall any Benchmark Replacement Conforming Changes be made, if in the Company’s
determination, the same could reasonably be expected to prejudice the qualification of the 2037 Notes as eligible liabilities or loss absorbing capacity instruments for the purposes of the Relevant Rules.

 (7) By its acquisition of the 2037 Notes, each Holder of the 2037 Notes (including each Holder of a beneficial interest in the
2037 Notes) (i) acknowledges, accepts, consents and agrees to be bound by the Company’s or its designee’s determination of a Benchmark Transition Event, a Benchmark Replacement Date, the Benchmark Replacement, the Benchmark
Replacement Adjustment and any Benchmark Replacement Conforming Changes, including as may occur without any prior notice from the Company and without the need for the Company to obtain any further consent from such Holder of the 2037 Notes,
(ii) shall waive any and all claims, in law and/or in equity, against the Trustee, the paying agent and the calculation agent or the Company’s designee for, agree not to initiate a suit against the Trustee, the paying agent and the

 39

calculation agent or the Company’s designee in respect of, and agree that none of the Trustee, the paying agent or the calculation agent or the Company’s designee shall be liable for,
the determination of or the Company’s failure or delay to determine any Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming
Changes, and any losses suffered in connection therewith and (iii) shall agree that none of the Trustee, the paying agent or the calculation agent or the Company’s designee shall have any obligation to determine, confirm or verify any
Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes (including any adjustments thereto), including in the event of any failure
or delay by the Company to determine any Benchmark Transition Event, any Benchmark Replacement Date, any Benchmark Replacement, any Benchmark Replacement Adjustment and any Benchmark Replacement Conforming Changes.

 (8) Except as set forth herein, all percentages resulting from any calculation of any interest rate for the 2037 Notes shall be
rounded, if necessary, to the nearest one hundred thousandth of a percentage point, with five one-millionths of a percentage point rounded upward (e.g., 9.876545% (or .09876545) would be rounded to 9.87655%
(or .0987655)), and all dollar amounts shall be rounded to the nearest cent, with one-half cent being rounded upward.

 (i) Place of Payment of Principal and Interest . Payment of the principal of (and premium, if any) and interest on the 2037 Notes will be
made at the office or agency of the Company maintained for that purpose in New York, New York, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts against
surrender of any Note in the case of any payment due at the 2037 Maturity Date; provided , however , that (i) if any Note is a Global Security, payments shall be made in respect of such Note pursuant to the Applicable Procedures of
the Depositary as in effect from time to time, and (ii) if any Note is not a Global Security, payment of interest in respect of such Note will be made by check mailed to the address of the Person entitled thereto as such address shall appear in
the Security Register at the close of business on the Regular Record Date for such interest. Notwithstanding the foregoing, if any Note is not a Global Security and has a principal amount of at least $1,000,000, upon request, the Company will pay
any amount that becomes due on such Note by wire transfer of immediately available funds to an account at a bank in New York City, on the due date. To request such a wire payment, the Holder of such Note must give the Paying Agent appropriate wire
transfer instructions at least five Business Days before the requested wire payment is due. In the case of any interest payment due on a 2037 Interest Payment Date, the instructions must be given by the person or entity who is the Holder on the
relevant Regular Record Date. Any wire instructions, once properly given, will remain in effect unless and until new instructions are given in the manner described above.

 (j) Optional Redemption .

 (1) On or after December 2, 2026 (180 days after the Issue Date) (or, if additional 2037 Notes are issued, beginning 180
days after the Issue Date of such additional 2037 Notes), and prior to the 2037 First Par Call Date, the Company may redeem the 2037 Notes at its option, in whole or in part, at any time and from time to time, at a Redemption Price (expressed as a
percentage of principal amount and rounded to three decimal places), equal to the greater of:

 40

 a. (i) The sum of the present values of the remaining scheduled payments of
principal and interest thereon discounted to the redemption date (assuming the 2037 Notes matured on the 2037 First Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 20 basis points less (ii) interest accrued to the date of redemption, and

 b. 100% of the principal amount of the 2037 Notes to be redeemed, plus in either case, accrued and unpaid interest thereon to
the redemption date.
 (2) On the 2037 First Par Call Date, the Company may redeem the 2037 Notes, in whole but not in part,
or on or after March 5, 2037 (which is the date that is three months prior to the 2037 Maturity Date), in whole or in part, at any time and from time to time, in each case at a redemption price equal to 100% of the principal amount of the 2037
Notes being redeemed plus accrued and unpaid interest thereon to the redemption date.
 In the case of a partial redemption, selection of
the 2037 Notes for redemption will be made pro rata, by lot or by such other method as required by the rules of DTC. No 2037 Notes of a principal amount of $2,000 or less will be redeemed in part. If any Note is to be redeemed in part only, the
notice of redemption that relates to the Note will state the portion of the principal amount of the note to be redeemed. A new Note in a principal amount equal to the unredeemed portion of the Note will be issued in the name of the Holder of the
note upon surrender for cancellation of the original Note. For so long as the 2037 Notes are held by DTC (or another depositary), the redemption of the 2037 Notes shall be done in accordance with the policies and procedures of the depositary.

 Unless the Company defaults in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the 2037
Notes or portions thereof called for redemption.
 Neither the Trustee nor the calculation agent shall be responsible for or have any
responsibility to determine or make any calculations in connection with any redemption.
 Notice of any redemption will be mailed or
electronically delivered at least 10 days but not more than 60 days before the redemption date to each Holder of the 2037 Notes to be redeemed, and at least fifteen days before the redemption date to the Trustee.

 (3) Solely for the purposes of this Section 3.02(j), the following terms shall have the following meanings:

 41

 a. “ 2037 First Par Call Date ” means June 5,
2036 (one year prior to the 2037 Maturity Date).
 b. “ Treasury Rate ” means, with respect to any
redemption date, the yield determined by the Company in accordance with the following two paragraphs:
 The Treasury Rate shall be
determined by the Company after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are post…

EX-5.1 · d297610dex51.htm

EX-5.1
 4
 d297610dex51.htm
 EX-5.1

 Exhibit 5.1

 [Letterhead of Wachtell, Lipton, Rosen & Katz]

 June 5, 2026
 Santander Holdings USA, Inc.

 75 State Street
 Boston, Massachusetts 02109

 Re:
 Issuance of 5.040%
 Fixed-to-Floating Rate Senior Notes due 2030, 5.220% Fixed-to-Floating Rate Senior Notes
due 2032 and 5.701% Fixed-to-Floating Rate Senior Notes due 2037 by Santander Holdings USA, Inc.

 Ladies and Gentlemen:
 We have acted as special
counsel to Santander Holdings USA, Inc., a Virginia corporation (the “ Company ”), in connection with the offering and sale by the Company of $1,000,000,000 aggregate principal amount of 5.040% Fixed-to-Floating Rate Senior Notes due 2030, $750,000,000 aggregate principal amount of Fixed-to-Floating Rate Senior Notes due
2032 and $750,000,000 aggregate principal amount of 5.701% Fixed-to-Floating Rate Senior Notes due 2037 (collectively, the “ Securities ”) in an
underwritten public offering pursuant to the Underwriting Agreement, dated June 2, 2026, between the Company and Santander US Capital Markets LLC, BofA Securities, Inc., Citigroup Global Markets Inc., J.P. Morgan Securities LLC, Morgan
Stanley & Co. LLC and RBC Capital Markets, for themselves and as representatives of the several underwriters listed therein (the “ Underwriting Agreement ”). The Securities are to be issued pursuant to that certain Senior
Debt Indenture, dated as of April 19, 2011 (the “ Senior Debt Indenture ”), between the Company and Deutsche Bank Trust Company Americas, as trustee (the “ Trustee ”), as amended by the Eighth Supplemental
Indenture, dated as of March 1, 2017 (the “ Eighth Supplemental Indenture ”), between the Company and the Trustee and as supplemented by the Thirty-Sixth Supplemental Indenture, dated as of the date hereof (together with the
Senior Debt Indenture and the Eighth Supplemental Indenture, the “ Indenture ”), between the Company and the Trustee.

 Santander Holdings USA, Inc.

 June 5, 2026
 Page 2

 We have examined: (i) the Registration Statement on Form
 S-3 (Registration No. 333-276089) filed with the Securities and Exchange Commission (the “ Commission ”) under the Securities Act of 1933, as
amended (the “ Securities Act ”), on December 15, 2023 by the Company; (ii) the preliminary prospectus dated June 2, 2026 forming a part thereof (the “ Preliminary Prospectus ”); (iii) the final
prospectus dated June 2, 2026 in the form filed with the Commission pursuant to Rule 424(b) under the Securities Act on June 4, 2026 (the “ Final Prospectus ”, and together with the Preliminary Prospectus, the
“ Prospectus ”) in connection with the offering and sale by the Company of the Securities; (iv) the Indenture; (v) the forms of the Securities and (vi) such other corporate records, certificates and other documents
and such matters of law, in each case, as we have deemed necessary or appropriate.
 In rendering this opinion, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to authentic original documents of all documents submitted to us as copies and the legal capacity of all individuals executing such
documents. As to any facts material to this opinion which we did not independently establish or verify, we have, with your consent, relied upon the statements, certificates and representations of the public officials, officers of the Company and
other representatives of parties to the Indenture and the Securities. We have also assumed the valid authorization, execution and delivery of the Indenture and the Securities by each party thereto other than the Company, and we have assumed that
each such other party (in the case of parties which are not natural persons) has been duly organized and is validly existing and in good standing under its jurisdiction of organization, that each such other party has the legal capacity, power and
authority to perform its obligations thereunder and that each of the Indenture and the Securities constitutes the valid and binding obligation of all such other parties, enforceable against them in accordance with its terms.

 Based upon the foregoing and subject to the qualifications, assumptions and limitations stated herein, we are of the opinion that the
Securities constitute a valid and legally binding obligation of the Company, enforceable against the Company in accordance with their terms.

 The opinion set forth above is subject to the effects of (i) bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium
and other similar laws relating to or affecting the enforcement of creditors’ rights generally, (ii) general equitable principles (whether considered in a proceeding in equity or at law) and (iii) an implied covenant of good faith
and fair dealing.
 We express no opinion as to whether, or the extent to which, the laws of any particular jurisdiction apply to the
subject matter hereof, including, without limitation, the enforceability of the governing law provision contained in any Securities or in any agreement and we express no opinion as to the enforceability of any indemnification or contribution
provisions contained in any agreement insofar as enforcement of these provisions may be limited by applicable federal securities laws or principles of public policy.

 We are members of the Bar of the State of New York. This opinion is limited to the laws of the State of New York and the federal securities
laws of the United States, and we express no opinion as to the effect on the matters covered by this opinion of the laws of any other jurisdiction.

 Insofar as the opinions expressed herein relate to or are dependent upon matters governed by the laws of the Commonwealth of Virginia, we have
relied, without independent investigation, upon the opinion dated the date hereof of Lucosky Brookman LLP, special counsel to the Company.

 Santander Holdings USA, Inc.

 June 5, 2026
 Page 3

 We hereby consent to the filing of this opinion as Exhibit 5.1 to the Company’s Current
Report on Form 8-K filed with the Commission on the date hereof and to the reference to us under the caption “Validity of the Notes” in the Prospectus that forms a part of the Registration
Statement. In giving such consent, we do not thereby admit that we are an expert within the meaning of Section 7 of the Act. We assume no obligation to advise the Company or any other person, or to make any investigations, as to any legal
developments or factual matters arising subsequent to the date hereof that might affect the opinions expressed herein.
 Very truly yours,

 /s/ Wachtell, Lipton, Rosen & Katz

EX-5.2 · d297610dex52.htm

EX-5.2
 5
 d297610dex52.htm
 EX-5.2

 Exhibit 5.2

 June 5, 2026

 Board of Directors
 Santander Holdings USA, Inc.

 75 State Street
 Boston, Massachusetts 02109

 Ladies and Gentlemen:
 Santander Holdings USA,
Inc., a Virginia corporation (the “ Company ”) filed ae Registration Statement on Form S-3 (File No. 333-276089) (the “ Registration
Statement ”) with the Securities and Exchange Commission (the “ SEC ”) in connection with the registration under the Securities Act of 1933, as amended (the “ Act ”), of certain securities, including the
Debt Securities of the Company, and the issuance by the Company of up to $1,000,000,000 aggregate principal amount of the 5.040% Fixed-to-Floating Rate Senior Notes due
2030, $750,000,000 aggregate principal amount of the 5.220% Fixed-to-Floating Rate Senior Notes due 2032 and $750,000,000 aggregate principal amount of the 5.701% Fixed-to-Floating Rate Senior Notes due 2037 (collectively the “ Notes ”) as described in the Company’s Prospectus, dated December 15, 2023 (the
“ Prospectus ”) and Prospectus Supplement, dated June 2, 2026 (the “ Prospectus Supplement ”). The Registration Statement became effective on December 15, 2023. We have acted as special counsel to the
Company in connection with the issuance of the Notes. This opinion letter is being furnished in accordance with the requirements of Item 16 of Form S-3 and Item 601(b)(5)(i) of Regulation S-K promulgated under the Act.
 The Notes are being issued pursuant to a Senior Debt Indenture, dated
April 19, 2011 (the “ Senior Debt Indenture ”), between the Company and Deutsche Bank Trust Company Americas, as trustee (the “ Trustee ”), as amended by the Eighth Supplemental Indenture, dated as of
March 1, 2017 (the “ Eighth Supplemental Indenture ”) between the Company and the Trustee, and as supplemented by the Thirty-seventh Supplemental Indenture, dated June 5, 2026 (the “ Thirty-seventh Supplemental
Indenture ” and collectively with the Eighth Supplemental Indenture and the Senior Debt Indenture, the “ Indenture ”), between the Company and the Trustee. The Notes are being offered to the public pursuant to an
underwriting agreement, dated June 2, 2026 (the “ Underwriting Agreement ”), by and among the Company, and the Underwriters listed in Schedule I to the Underwriting Agreement. Capitalized terms used and not defined herein shall
have the meanings assigned to them in the Registration Statement or the Underwriting Agreement.

 Documents Reviewed

 In connection with this opinion letter, we have examined the following documents:

 (a) the Registration Statement;

 (b) the Prospectus;
 (c) the
Prospectus Supplement;
 (d) the Indenture; and

 (e) the Underwriting Agreement.

 In addition, we have examined and relied upon the following:

 a certificate from the assistant secretary of the Company certifying as to (A) true, correct and complete copies of the
Amended and Restated Articles of Incorporation and the Amended and Restated Bylaws of the Company and (B) the resolutions of the Board of Directors of the Company adopted on or as of January 27, 2011, December 9, 2016,
December 14, 2023 and November 24, 2025;
 a certificate dated June 4, 2026 issued by the Office of the Clerk
of the State Corporation Commission of the Commonwealth of Virginia attesting to the corporate status of the Company in the Commonwealth of Virginia (the “Good Standing Certificate”); and

 originals, or copies identified to our satisfaction as being true copies, of such other records, documents and instruments as
we have deemed necessary for the purposes of this opinion letter.
 “ Applicable Law ” means the law of the Commonwealth of
Virginia.
 Assumptions Underlying Our Opinions

 For all purposes of the opinions expressed herein, we have assumed, without independent investigation, the following:

 (a) Factual Matters . To the extent that we have reviewed and relied upon (i) certificates of the Company or authorized
representatives thereof and (ii) certificates and assurances from public officials, all of such certificates and assurances are accurate with regard to factual matters.

 (b) Authentic and Conforming Documents . All documents submitted to us as originals are authentic, complete and accurate, and all
documents submitted to us as copies conform to authentic original documents.

 2

 Our Opinions

 Based on and subject to the foregoing and the exclusions, qualifications, limitations and other assumptions set forth in this opinion letter,
we are of the opinion that:
 1. Organizational Status . The Company is a validly existing corporation and is in good standing under
the laws of the Commonwealth of Virginia, as of the date set forth in the Good Standing Certificate.
 2. Authorization . The Company
has the corporate power and authority to issue the Notes and has taken all necessary corporate action to authorize the issuance of the Notes.

 Qualification and Limitation Applicable to Our Opinions

 The opinions set forth above are limited to the Applicable Law, and we do not express any opinion concerning any other law.

 Miscellaneous
 The
foregoing opinion is being furnished only for the purpose referred to in the first paragraph of this opinion letter. Our opinions are based on statutes, regulations and administrative and judicial interpretations which are subject to change. We
undertake no responsibility to update or supplement these opinions subsequent to the date hereof. We hereby consent to the filing of this opinion as an exhibit to the Company’s Current Report on Form 8-K
and the incorporation of this opinion by reference in the Registration Statement and to references to us under the caption “Validity of Offered Securities” appearing in the prospectus that is part of the Registration Statement and under
the caption “Validity of the Notes” appearing in the prospectus supplement relating to the Notes. In giving this consent, we do not admit that we are within the category of persons whose consent is required by Section 7 of the
Securities Act or the rules and regulations of the SEC promulgated thereunder.
 Very truly yours,

 /s/ Lucosky Brookman LLP

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