Alnylam (ALNY) CSO’s 1,291-share Rule 10b5-1 stock sale detailed

Rhea-AI Filing Summary

Alnylam Pharmaceuticals CSO & EVP, Head of Research Kevin Joseph Fitzgerald reported open-market sales of company stock. On March 4–5, 2026, he sold a total of 1,291 shares of common stock in multiple transactions at prices generally in the low $320 range.

Footnotes state that some shares were automatically sold by the company under a mandatory sell-to-cover provision to satisfy minimum tax withholding on vested restricted stock units, and that the transactions were made under a Rule 10b5-1(c) trading plan adopted on August 14, 2025. After these sales, Fitzgerald directly owns 20,569 common shares and indirectly holds 537 shares through a managed account associated with the company’s 401(k) matching program.

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).

X

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^*

Fitzgerald Kevin Joseph

(Last) (First) (Middle)

675 WEST KENDALL STREET

HENRI A. TERMEER SQUARE

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
ALNYLAM PHARMACEUTICALS, INC. [ ALNY ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CSO & EVP, Head of Research

3. Date of Earliest Transaction (Month/Day/Year)
03/04/2026

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

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

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

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	03/04/2026		S(1)		29	D	$319.03(2)	21,831	D
Common Stock	03/04/2026		S(1)		28	D	$320.01(3)	21,803	D
Common Stock	03/04/2026		S(1)		59	D	$320.81(4)	21,744	D
Common Stock	03/04/2026		S(1)		79	D	$321.82(5)	21,665	D
Common Stock	03/04/2026		S(1)		96	D	$323.01(6)	21,569	D
Common Stock	03/04/2026		S(1)		210	D	$323.84(7)	21,359	D
Common Stock	03/04/2026		S(1)		75	D	$324.88(8)	21,284	D
Common Stock	03/04/2026		S(1)		57	D	$325.67(9)	21,227	D
Common Stock	03/05/2026		S(10)		124	D	$321.81(11)	21,103	D
Common Stock	03/05/2026		S(10)		233	D	$323.25(12)	20,870	D
Common Stock	03/05/2026		S(10)		148	D	$324.6(13)	20,722	D
Common Stock	03/05/2026		S(10)		153	D	$326.24(14)	20,569	D
Common Stock								537	I	by Managed Account(15)

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

Explanation of Responses:

1. Represents shares automatically sold by the Company on behalf of the reporting person pursuant to a mandatory sell-to-cover provision in the award agreement to cover minimum statutory tax withholding obligations upon the vesting of restricted stock units.

2. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $318.27 to $319.27. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

3. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $319.28 to $320.28. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

4. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $320.33 to $321.33. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

5. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $321.34 to $322.31. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

6. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $322.36 to $323.36. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

7. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $323.38 to $324.35. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

8. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $324.39 to $325.38. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

9. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $325.40 to $326.21. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

10. This transaction was made pursuant to a Rule 10b5-1(c) trading plan adopted by the Reporting Person on August 14, 2025.

11. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $321.43 to $322.00. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

12. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $322.81 to $323.65. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

13. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $324.36 to $325.01. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

14. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $326.01 to $326.40. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.

15. Reflects shares of ALNY common stock acquired by the Reporting Person under the issuer 401(k) plan as a result of the issuer 401(k) matching contribution program.

	By: Brett Budzinski, Attorney-in-Fact For: Kevin Fitzgerald	03/06/2026
	** Signature of Reporting Person	Date
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