Merck (MRK)

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2025-12-31 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: Merck & Co., Inc. (MRK) CIK: 0000310158 --- Reporting Owner --- Name: Seidman Christine E CIK: 0001805745 Role: Director --- Derivative Transactions --- [Transaction #1] Security: Phantom Stock Date: 2025-12-31 | Code: A (Grant or award) Shares: +77.1898 | Price: $105.26 Shares Owned After: 19,025.6686 | Ownership: D (Direct) Footnotes: [F1] 1-for-1 [F2] Phantom stock units are to be settled 100% in cash upon reporting person's termination of service in accordance with a distribution schedule elected pursuant to the terms of the Plan for Deferred Payment of Directors' Compensation. [F2] Phantom stock units are to be settled 100% in cash upon reporting person's termination of service in accordance with a distribution schedule elected pursuant to the terms of the Plan for Deferred Payment of Directors' Compensation. [F3] Holdings include shares acquired in dividend reinvestment transactions. --- Holdings --- [Holding #1] Security: Common Stock Ownership: D (Direct) --- Footnotes (Complete Index) --- F1: 1-for-1 F2: Phantom stock units are to be settled 100% in cash upon reporting person's termination of service in accordance with a distribution schedule elected pursuant to the terms of the Plan for Deferred Payment of Directors' Compensation. F3: Holdings include shares acquired in dividend reinvestment transactions. --- Signature --- /s/ /s/ Kelly E. W. Grez as Attorney-in-Fact for Christine E. Seidman (2026-01-05)