[Form 4] Merck & Co., Inc. Insider Trading Activity

Rhea-AI Filing Summary

Merck & Co., Inc. Executive VP & President, MRL, Dean Y. Li exercised restricted stock units and settled related taxes in shares. On April 29, 2026, 4,722 restricted stock units converted into the same number of common shares, while 2,326 shares were withheld to cover tax obligations at $110.03 per share.

After these transactions, Li directly owned 96,757.05 shares of Merck common stock and held 9,444 restricted stock units outstanding. The RSUs vest and are distributed in three equal installments on April 29, 2026, April 29, 2027, and April 29, 2028.

Insider Trade Summary

4,722 shares exercised/converted

Mixed 3 txns

Insider Li Dean Y

Role Executive VP & President, MRL

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Unit	4,722	$0.00	--
Exercise	Common Stock	4,722	$110.03	$520K
Tax Withholding	Common Stock	2,326	$110.03	$256K

Holdings After Transaction: Restricted Stock Unit — 9,444 shares (Direct, null); Common Stock — 96,757.05 shares (Direct, null)

Footnotes (1)

1. Each restricted stock unit represents a contingent right to receive one share of Merck & Co., Inc. common stock. These restricted stock units vest and are distributed as shares of Merck & Co., Inc. common stock in three equal installments on 4/29/2026, 4/29/2027 and 4/29/2028.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Li Dean Y

(Last) (First) (Middle)

MERCK & CO., INC.

126 EAST LINCOLN AVENUE

(Street)

RAHWAY NEW JERSEY 07065

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Merck & Co., Inc. [ MRK ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Executive VP & President, MRL

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/29/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	04/29/2026		M		4,722	A	$110.03	96,757.05	D
Common Stock	04/29/2026		F		2,326	D	$110.03	94,431.05	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Unit	(1)	04/29/2026		M			4,722	04/29/2026(2)	04/29/2028	Common Stock	4,722	$0	9,444	D

Explanation of Responses:

1. Each restricted stock unit represents a contingent right to receive one share of Merck & Co., Inc. common stock.

2. These restricted stock units vest and are distributed as shares of Merck & Co., Inc. common stock in three equal installments on 4/29/2026, 4/29/2027 and 4/29/2028.

	/s/ Kelly E. W. Grez as Attorney-in-Fact for Dean Y. Li	05/01/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)