Form of Master Global Note for the Subordinated Senior B Notes

Exhibit 4.3(b)

THIS MASTER GLOBAL NOTE IS AN OBLIGATION OF SOLELY M&T BANK CORPORATION AND IS NOT A DEPOSIT OR OTHER OBLIGATION OF MANUFACTURERS AND TRADERS TRUST COMPANY, WILMINGTON TRUST, NATIONAL ASSOCIATION OR ANY OTHER BANK AND IS NOT INSURED OR GUARANTEED BY THE FEDERAL DEPOSIT INSURANCE CORPORATION OR ANY OTHER GOVERNMENTAL AGENCY OR INSURER.

EACH PURCHASER OR HOLDER OF THIS MASTER GLOBAL NOTE OR ANY INTEREST THEREIN WILL BE DEEMED TO HAVE REPRESENTED BY ITS PURCHASE OR HOLDING OF THIS MASTER GLOBAL NOTE OR ANY INTEREST THEREIN THAT (A) IT IS NOT A PLAN (INCLUDING A PENSION, PROFIT-SHARING OR OTHER EMPLOYEE BENEFIT PLAN SUBJECT TO THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), AND AN ENTITY SUCH AS A COLLECTIVE INVESTMENT FUND, A PARTNERSHIP, A SEPARATE ACCOUNT WHOSE UNDERLYING ASSETS INCLUDE THE ASSETS OF SUCH PLANS, AN INDIVIDUAL RETIREMENT ACCOUNT, A KEOGH PLAN FOR SELFEMPLOYED INDIVIDUALS AND ANY OTHER PLAN THAT IS SUBJECT TO SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE “CODE”)) AND ITS PURCHASE, HOLDING AND SUBSEQUENT DISPOSITION OF THIS MASTER GLOBAL NOTE OR ANY INTEREST THEREIN IS NOT MADE ON BEHALF OF OR WITH “PLAN ASSETS” OF ANY PLAN WITHIN THE MEANING OF U.S. DEPARTMENT OF LABOR REGULATION SECTION 2510.3-101 AS MODIFIED BY ERISA SECTION 3(42), OR (B) ITS PURCHASE, HOLDING AND SUBSEQUENT DISPOSITION OF THIS MASTER GLOBAL NOTE OR ANY INTEREST THEREIN WILL NOT RESULT IN A NONEXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE. IN ADDITION, EACH PURCHASER OR HOLDER OF THIS MASTER GLOBAL NOTE OR ANY INTEREST THEREIN WILL BE DEEMED TO HAVE REPRESENTED BY ITS PURCHASE OR HOLDING OF THIS MASTER GLOBAL NOTE OR ANY INTEREST THEREIN THAT SUCH PURCHASE, HOLDING AND SUBSEQUENT DISPOSITION IS NOT AND WILL NOT BE PROHIBITED UNDER SIMILAR RULES TO THE “PROHIBITED TRANSACTION” RULES OF ERISA OR SECTION 4975 OF THE CODE UNDER OTHER APPLICABLE LAWS OR REGULATIONS.

THIS SECURITY IS SUBORDINATED, AS TO PRINCIPAL, INTEREST AND PREMIUM, AND ADDITIONAL AMOUNTS, IF ANY, TO ALL “SENIOR INDEBTEDNESS” AND “OTHER FINANCIAL OBLIGATIONS” OF M&T BANK CORPORATION, INCLUDING ALL OBLIGATIONS TO M&T BANK CORPORATION’S GENERAL CREDITORS (OTHER THAN OBLIGATIONS TO TRADE CREDITORS INCURRED IN THE ORDINARY COURSE OF M&T BANK CORPORATION’S BUSINESS). THIS SECURITY IS NOT SECURED BY ANY ASSETS OF M&T BANK CORPORATION OR BY THE ASSETS OF ANY OF ITS SUBSIDIARIES OR AFFILIATES, IS NOT GUARANTEED BY ANY OF M&T BANK CORPORATION’S SUBSIDIARIES OR AFFILIATES, AND IS INELIGIBLE AS COLLATERAL TO SECURE A LOAN OR EXTENSION OF CREDIT FROM M&T BANK CORPORATION OR ANY OF ITS SUBSIDIARIES.

If the registered owner of this Master Global Note (as indicated below) is The Depository Trust Company (“DTC”) or a nominee of DTC, this Master Global Note is a Global Security, is subject to all applicable procedures of DTC, and the following legend applies:

Unless this certificate is presented by an authorized representative of The Depository Trust Company (the “Depository”) to the issuer or its agent for registration of transfer, exchange or payment, and such certificate issued is registered in the name of CEDE & CO., or such other name as requested by an authorized representative of the Depository (and any payment is made to CEDE & CO. or such other entity as may be requested by an authorized representative of the Depository), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL, since the registered owner hereof, CEDE & CO., has an interest herein.

If the registered owner of this Master Global Note (as indicated below) is [__________________] (“[____]”) or a nominee of [_________], this Master Global Note is a Global Security and the following legend applies:

[Unless this certificate is presented by an authorized representative of [______________] (the “Depository”) to the issuer or its agent for registration of transfer, exchange, or payment, and any certificate issued is registered in the name of [______________] or in such other name as is requested by an authorized representative of the Depository (and any payment is made to [______________] or to such other entity as is requested by an authorized representative of the Depository), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, [______________], has an interest herein.]

Thereafter the following legend applies, regardless of the registered owner of this Security:

Unless and until this certificate is exchanged in whole or in part for Notes in certificated form, this certificate may not be transferred except as a whole by the Depository to a nominee thereof or by a nominee thereof to the Depository or another nominee of the Depository or by the Depository or any such nominee to a successor of the Depository or a nominee of such successor.

M&T BANK CORPORATION, a New York corporation (herein referred to as the “Issuer,” which term includes any successor corporation under the Indenture hereinafter referred to), for value received, hereby promises to pay to [_________], or its registered assigns: (i) on each principal payment date, including each redemption date, repayment date, and maturity date, as applicable, of each obligation identified on the records of the Issuer (which records are maintained by The Bank of New York Mellon, or such other paying agent as designated in the

applicable pricing supplement (the “Paying Agent”)) as being evidenced by this Master Global Note, the principal amount then due and payable for each such obligation, and (ii) on each interest payment date, if any, the interest then due and payable on the principal amount for each such obligation. Payment shall be made by wire transfer of United States dollars to the registered owner, or immediately available funds or the equivalent to a party as authorized by the registered owner and in the currency other than United States dollars as provided for in each such obligation, by the Paying Agent without the necessity of presentation and surrender of this Master Global Note.

REFERENCE IS HEREBY MADE TO THE FURTHER PROVISIONS OF THIS MASTER GLOBAL NOTE SET FORTH ON THE REVERSE HEREOF, WHICH FURTHER PROVISIONS SHALL FOR ALL PURPOSES HAVE THE SAME EFFECT AS IF SET FORTH AT THIS PLACE, INCLUDING, WITHOUT LIMITATION, THE PROVISIONS RELATING TO THE SUBORDINATION OF THIS SECURITY TO THE ISSUER’S SENIOR INDEBTEDNESS AND OTHER FINANCIAL OBLIGATIONS.

This Master Global Note is a valid and binding obligation of the Issuer.

Unless the certificate of authentication hereon has been executed by the Trustee referred to on the reverse hereof by manual signature (or, solely in the case of a Global Security, facsimile or electronic signature; provided that any electronic signature complying with the New York Electronic Signatures and Records Act (N.Y. State Tech. §§ 301-309) is permissible), this Master Global Note shall not be entitled to any benefit under the Indenture referred to on the reverse hereof or be valid or obligatory for any purpose.

IN WITNESS WHEREOF, the Issuer has caused this instrument to be duly executed under its corporate seal.

[REVERSE OF NOTE]

M&T BANK CORPORATION

SUBORDINATED MEDIUM-TERM NOTE, SERIES B

(MASTER GLOBAL NOTE)

This Master Global Note evidences certain indebtedness (the “Debt Obligations”) of the Issuer, which shall form a part of the Issuer’s unsecured, subordinated medium-term notes, Series B due nine months or more from the date of issue (“Series B”), all issued or to be issued under and pursuant to an Indenture dated as of September 22, 2023 (as may be supplemented or amended from time to time, the “Indenture”), duly executed and delivered by the Issuer to The Bank of New York Mellon, as trustee (the “Trustee”), to which Indenture and the Issuer’s Officers’ Certificate (the “Officers’ Certificate”), dated September 22, 2023, with respect to, among other things, the establishment of Subordinated Medium-Term Notes, Series B, reference is hereby made for a description of the rights, duties and immunities thereunder of the Issuer, the Trustee and the holders of the Debt Obligations. In accordance with the Indenture and the Officers’ Certificate, the Debt Obligations may mature at different times, may bear interest, if any, at different rates, may be subject to different redemption and repayment provisions, if any, may be subject to different sinking, purchase, or analogous funds, if any, may be subject to different covenants and events of default, and may otherwise vary as provided or permitted in the Indenture or the Officers’ Certificate. Copies of the Indenture and the Officers’ Certificate are available from the Issuer or the Trustee. The Debt Obligations as evidenced by this Master Global Note aggregated with any other indebtedness of the Issuer issued under Series B are unlimited.

REFERENCE IS HEREBY MADE TO THE FURTHER PROVISIONS OF THE DEBT OBLIGATIONS SET FORTH IN THE RECORDS OF THE ISSUER MAINTAINED BY THE TRUSTEE, WHICH RECORDS CONSIST OF THE APPLICABLE PRICING SUPPLEMENT(S) TO THE PROSPECTUS SUPPLEMENT AND PROSPECTUS REFERENCED THEREIN RELATING TO EACH ISSUANCE OF DEBT OBLIGATIONS, AS FILED BY THE ISSUER WITH THE SECURITIES AND EXCHANGE COMMISSION, WHICH DOCUMENTS ARE ON FILE WITH THE TRUSTEE AND WHICH PRICING SUPPLEMENT IS IDENTIFIED ON SCHEDULE A HERETO. THE “DESCRIPTION OF THE NOTES” SECTION SET FORTH IN THE PROSPECTUS SUPPLEMENT AND THE APPLICABLE PRICING SUPPLEMENT(S) SHALL FOR ALL PURPOSES HAVE THE SAME EFFECT AS THOUGH FULLY SET FORTH HEREIN AND SHALL COMPRISE A PART OF THIS MASTER GLOBAL NOTE.

Capitalized terms used herein that are not defined herein shall have the meanings assigned to them in the Indenture or the Officers’ Certificate.

The Debt Obligations evidenced by this Master Global Note are, to the extent and in the manner provided in the Indenture and the Officers’ Certificate referred to above, subordinate and subject in right of payment to the prior payment in full of the principal of and premium, if any, and interest on all Senior Indebtedness of the Issuer, as defined in the Indenture, and each holder of the Debt Obligations of this Master Global Note, by accepting the same, agrees to and shall be bound by the provisions of the Indenture and the Officers’ Certificate and authorizes and directs the Trustee on his behalf to take such action as may be necessary or appropriate to acknowledge

or effectuate the subordination of this Master Global Note as provided in the Indenture and the Officers’ Certificate and appoints the Trustee his attorney-in-fact for any and all such purposes. The Indenture provides that in the event of insolvency, bankruptcy, receivership, reorganization, liquidation or similar proceedings of the Issuer (an “insolvency event”), all Senior Indebtedness of the Issuer shall be entitled to be paid in full before any payment shall be made on, the Debt Obligations. Each holder of the Debt Obligations, by accepting the same, agrees that each holder of Senior Indebtedness, whether created or acquired before or after the issuance of the Debt Obligations, shall be deemed conclusively to have relied on such provisions in acquiring and continuing to hold, or in continuing to hold, such Senior Indebtedness.

The Debt Obligations evidenced by this Master Global Note are issued subject to the provisions of the Indenture regarding payments to creditors in respect of Other Financial Obligations. In particular, the Indenture provides that if upon the occurrence of an insolvency event relating to the Issuer, there remains, after giving effect to the subordination provisions referred in the preceding paragraph, any amount of cash, property or securities available for payment or distribution in respect of this Master Global Note (as defined in the Indenture, “Excess Proceeds”), and if, at such time, any creditors in respect of Other Financial Obligations have not received payment in full of all amounts due or to become due on or in respect of such Other Financial Obligations, then such Excess Proceeds shall first be applied to pay or provide for the payment in full of such Other Financial Obligations before any payment or distribution may be made in respect of this Master Global Note.

Subject to the rights of holders of Senior Indebtedness and Other Financial Obligations of the Issuer set forth in this Master Global Note and as provided in the Indenture referred to above, no reference herein to the Indenture or the Officers’ Certificate and no provision of this Master Global Note, of the Indenture, or the of Officers’ Certificate shall alter or impair the obligation of the Issuer, which is absolute and unconditional, to pay the principal of, premium, if any, and interest, if any, on each Debt Obligation at the times, places, and rates, and in the coin or currency, identified on the records of the Issuer.

At the request of the registered owner, the Issuer shall promptly issue and deliver one or more separate note certificates evidencing each Debt Obligation evidenced by this Master Global Note. As of the date any such note certificate or certificates are issued, the Debt Obligations which are evidenced thereby shall no longer be evidenced by this Master Global Note.

Beneficial interests in the Debt Obligations evidenced by this Master Global Note are exchangeable for definitive notes in registered form, of like tenor and terms and of an equal aggregate principal amount, only if (a) (i) [The Depository Trust Company][________________], as depositary (the “Depository”), notifies the Issuer that it is unwilling or unable to continue as Depository for this Master Global Note, or (ii) if at any time the Depository ceases to be a clearing agency registered under the Securities Exchange Act of 1934, as amended, if then required by applicable law or regulation, and in either case, a successor depositary is not appointed by the Issuer within 90 days after receiving notice or becoming aware the Depository is unwilling or unable to continue as depositary or is no longer so registered; (b) the Issuer in its sole discretion elects to issue definitive notes; or (c) any event shall have occurred and be continuing which, after notice or lapse of time, or both, would constitute a Default with respect to this Master Global Note. Any beneficial interests in such

Debt Obligation that are exchangeable pursuant to the preceding sentence shall be exchangeable for definitive notes in fully registered form, of like tenor and of an equal aggregate principal amount, in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof, unless otherwise specified in the applicable Pricing Supplement. Such definitive notes shall be registered in the name or names of such person or persons as the Depository shall instruct the registrar.

Prior to due presentment of this Master Global Note for registration of transfer, the Issuer, the Trustee or any agent of the Issuer or the Trustee may treat the holder in whose name this Master Global Note is registered as the absolute owner hereof for all purposes, whether or not this Master Global Note be overdue, and neither the Issuer, the Trustee nor any such agent shall be affected or incur any liability by notice to the contrary except as required by applicable law.

This Master Global Note shall be governed by and construed in accordance with the laws of the State of New York.

ASSIGNMENTS

FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s) and transfer(s) unto:

(Please print or type Name, Address, and Taxpayer Identification Number of Assignee)

the Master Global Note of M&T BANK CORPORATION and all rights thereunder and does hereby irrevocably constitute and appoint:

attorney to transfer the said Master Global Note on the books of the within-named Issuer, with full power of substitution in the premises.

SIGNATURE GUARANTEED:

SCHEDULE A