SCHEDULE 13G 0001535978 XXXXXXXX LIVE Common Stock, par value $0.01 per share 12/31/2025 0001476034 Metropolitan Bank Holding Corp. 591774104 99 PARK AVENUE NEW YORK NY 10016 Rule 13d-1(b) Adage Capital Management, L.P. DE 0.00 559479.00 0.00 559479.00 559479.00 N 5.43 IA PN Robert Atchinson X1 0.00 559479.00 0.00 559479.00 559479.00 N 5.43 HC IN Phillip Gross X1 0.00 559479.00 0.00 559479.00 559479.00 N 5.43 HC IN Metropolitan Bank Holding Corp. 99 Park Avenue, New York, NY 10016 This statement is filed by: (i) Adage Capital Management, L.P., a Delaware limited partnership ("ACM"), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership ("ACP"), with respect to the Common Stock, par value $0.01 per share ("Common Stock") of Metropolitan Bank Holding Corp., a New York corporation (the "Company") directly held by ACP; (ii) Robert Atchinson ("Mr. Atchinson"), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACA"), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACPGP"), general partner of ACP and (2) managing member of Adage Capital Partners LLC, a Delaware limited liability company ("ACPLLC"), general partner of ACM, with respect to the Common Stock directly held by ACP; and (iii) Phillip Gross ("Mr. Gross"), as (1) managing member of ACA, managing member of ACPGP and (2) managing member of ACPLLC, general partner of ACM, with respect to the Common Stock directly held by ACP. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party. The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of the securities reported herein. The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116. ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States. N IA HC The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 10,298,002 shares of Common Stock outstanding as of November 3, 2025, as reported in the Company's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2025, filed with the Securities and Exchange Commission on November 7, 2025. 5.43% The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference. Y N See Item 2(a). Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Exhibit 99.1: Joint Filing Agreement Adage Capital Management, L.P. /s/ Robert Atchinson 02/12/2026 Robert Atchinson /s/ Robert Atchinson 02/12/2026 Phillip Gross /s/ Phillip Gross 02/12/2026