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: 2026-05-05 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: Merck & Co., Inc. (MRK) CIK: 0000310158 --- Reporting Owner --- Name: Litchfield Caroline CIK: 0001854928 Role: Officer (EVP & CFO) --- Derivative Transactions --- [Transaction #1] Security: Restricted Stock Unit Date: 2026-05-05 | Code: A (Grant or award) Shares: +15,908 | Price: $0.00 Exercisable: N/A | Expires: 2029-05-05 Shares Owned After: 15,908 | Ownership: D (Direct) Footnotes: [F1] Each restricted stock unit represents a contingent right to receive one share of Merck & Co., Inc. common stock. [F2] These restricted stock units vest and are distributed as shares of Merck & Co., Inc. common stock in three equal installments on 5/5/2027, 5/5/2028, and, 5/5/2029. [Transaction #2] Security: Stock Option (Right to Buy) Date: 2026-05-05 | Code: A (Grant or award) Shares: +46,566 | Price: $0.00 Exercisable: N/A | Expires: 2036-05-04 Shares Owned After: 46,566 | Ownership: D (Direct) Footnotes: [F3] The option vests and becomes exercisable in equal installments on 5/5/2027, 5/5/2028, and, 5/5/2029. --- Holdings --- [Holding #1] Security: Common Stock Ownership: D (Direct) --- Footnotes (Complete Index) --- F1: Each restricted stock unit represents a contingent right to receive one share of Merck & Co., Inc. common stock. F2: These restricted stock units vest and are distributed as shares of Merck & Co., Inc. common stock in three equal installments on 5/5/2027, 5/5/2028, and, 5/5/2029. F3: The option vests and becomes exercisable in equal installments on 5/5/2027, 5/5/2028, and, 5/5/2029. --- Signature --- /s/ /s/ Kelly E. W. Grez as attorney-in-fact for Caroline Litchfield (2026-05-07)