Merck & Co., Inc. (MRK) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-05-29 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: Merck & Co., Inc. (MRK) CIK: 0000310158 --- Reporting Owner --- Name: Mayo Stephen CIK: 0001849061 Role: Director --- Derivative Transactions --- [Transaction #1] Security: Phantom Stock Date: 2026-05-29 | Code: A (Grant or award) Shares: +1,853.0997 | Price: $118.72 Shares Owned After: 14,824.5202 | 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 Stephen L. Mayo (2026-06-02)