Alnylam Pharmaceuticals (ALNY) CEO details PSU vesting and tax sales

Rhea-AI Filing Summary

Alnylam Pharmaceuticals Chief Executive Officer and director Yvonne Greenstreet reported equity awards and related share sales. On January 11, 2026, she acquired 19,003 shares of common stock at $0.0 upon vesting of 40% of a performance-based stock unit granted on March 1, 2024, after the company publicly reported $2.5 billion in annual net product revenue under GAAP, as determined by the board’s People, Culture and Compensation Committee.

On January 12, 2026, the company automatically sold multiple small blocks of Alnylam common stock on her behalf, coded as "S" transactions, pursuant to a mandatory sell-to-cover provision to satisfy minimum statutory tax withholding. These sales occurred at weighted average prices ranging from about $353.53 to $377.82 per share. After the reported transactions, she beneficially owned 78,411 shares directly and 407 shares indirectly through a managed account.

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^*

Greenstreet Yvonne

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
01/11/2026

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	01/11/2026		A(1)		19,003	A	$0.0	87,988	D
Common Stock	01/12/2026		S(2)		247	D	$353.95(3)	87,741	D
Common Stock	01/12/2026		S(2)		269	D	$355.16(4)	87,472	D
Common Stock	01/12/2026		S(2)		263	D	$356.09(5)	87,209	D
Common Stock	01/12/2026		S(2)		607	D	$357.17(6)	86,602	D
Common Stock	01/12/2026		S(2)		778	D	$358.18(7)	85,824	D
Common Stock	01/12/2026		S(2)		537	D	$359.14(8)	85,287	D
Common Stock	01/12/2026		S(2)		980	D	$360.22(9)	84,307	D
Common Stock	01/12/2026		S(2)		624	D	$361.45(10)	83,683	D
Common Stock	01/12/2026		S(2)		464	D	$362.38(11)	83,219	D
Common Stock	01/12/2026		S(2)		301	D	$363.55(12)	82,918	D
Common Stock	01/12/2026		S(2)		1,259	D	$364.83(13)	81,659	D
Common Stock	01/12/2026		S(2)		1,395	D	$365.56(14)	80,264	D
Common Stock	01/12/2026		S(2)		316	D	$366.41(15)	79,948	D
Common Stock	01/12/2026		S(2)		261	D	$367.4(16)	79,687	D
Common Stock	01/12/2026		S(2)		584	D	$368.62(17)	79,103	D
Common Stock	01/12/2026		S(2)		253	D	$369.48(18)	78,850	D
Common Stock	01/12/2026		S(2)		118	D	$370.87(19)	78,732	D
Common Stock	01/12/2026		S(2)		21	D	$372.46(20)	78,711	D
Common Stock	01/12/2026		S(2)		88	D	$374.44(21)	78,623	D
Common Stock	01/12/2026		S(2)		118	D	$375.65	78,505	D
Common Stock	01/12/2026		S(2)		94	D	$377.82	78,411	D
Common Stock								407	I	by Managed Account(22)

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. On March 1, 2024, the reporting person was granted a performance-based stock unit (PSU) under the 2018 Stock Incentive Plan. The shares subject to the PSU vest based on the achievement of three specified performance measures. The shares reported were issued to the reporting person upon vesting of forty (40) percent of the shares subject to the PSU based on the issuer publicly reporting $2.5 billion in annual net product revenue in accordance with GAAP, as determined by the People, Culture and Compensation Committee of the Issuer Board of Directors on January 11, 2026.

2. 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.

3. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $353.53 to $354.41. 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 $354.54 to $355.53. 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 $356.62 to $356.61. 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 $356.63 to $357.63. 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 $357.68 to $358.68. 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 $358.69 to $359.66. 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 $359.79 to $360.79. 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. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $360.90 to $361.89. 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.

11. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $361.93 to $362.92. 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 $362.99 to $363.99. 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 $364.00 to $365.00. 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.

14. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $365.01 to $366.01. 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.

15. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $366.03 to $366.96. 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.

16. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $367.04 to $368.00. 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.

17. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $368.09 to $369.08. 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.

18. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $369.13 to $369.93. 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.

19. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $370.43 to $371.23. 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.

20. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $372.35 to $372.50. 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.

21. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $374.08 to $374.89. 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.

22. 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: Yvonne Greenstreet	01/14/2026
	** 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.

FAQ

What insider activity did Alnylam (ALNY) report for CEO Yvonne Greenstreet?

The filing shows that Yvonne Greenstreet, Alnylam’s Chief Executive Officer and director, reported a grant-related share issuance and related share sales. She received 19,003 shares of common stock from a performance-based stock unit vesting on January 11, 2026, followed by multiple automatic sales on January 12, 2026 to cover tax withholding.

What triggered the vesting of performance-based stock units for Alnylam CEO Yvonne Greenstreet?

The performance-based stock unit (PSU) granted on March 1, 2024 vested in part when Alnylam publicly reported $2.5 billion in annual net product revenue in accordance with GAAP. Based on this achievement, as determined by the People, Culture and Compensation Committee on January 11, 2026, 40% of the PSU shares (equal to 19,003 shares) were issued to Ms. Greenstreet.

Were the Alnylam (ALNY) shares sold by the CEO discretionary sales or for tax withholding?

The filing states that the shares sold on January 12, 2026, coded as "S" transactions, represent shares automatically sold by the company on behalf of Ms. Greenstreet. These sales were made pursuant to a mandatory sell-to-cover provision in the award agreement to cover minimum statutory tax withholding obligations, rather than discretionary open-market sales.

At what prices were Alnylam (ALNY) CEO Yvonne Greenstreet’s shares sold on January 12, 2026?

The reported sales on January 12, 2026 occurred in multiple transactions at weighted average prices. Individual lines in the filing show weighted average sales prices such as $353.95, $355.16, $357.17, and up to $377.82 per share. Footnotes explain that each weighted average reflects numerous trades within specified price ranges, and detailed breakdowns are available upon request.

How many Alnylam (ALNY) shares does CEO Yvonne Greenstreet hold after these Form 4 transactions?

Following the reported grant-related issuance and automatic tax-withholding sales, Ms. Greenstreet beneficially owned 78,411 shares of Alnylam common stock directly. The filing also shows an indirect holding of 407 shares of common stock held by a managed account as of January 11, 2026.

What does the Form 4 say about Alnylam (ALNY) CEO’s 401(k) plan holdings?

A footnote explains that 407 shares of Alnylam common stock are held in a managed account and reflect shares acquired under the issuer’s 401(k) plan as a result of the company’s 401(k) matching contribution program. These are reported as indirect beneficial ownership.

What is the nature of the performance-based stock unit (PSU) granted to Alnylam CEO Yvonne Greenstreet?

The PSU was granted on March 1, 2024 under Alnylam’s 2018 Stock Incentive Plan. The shares subject to the PSU vest based on the achievement of three specified performance measures. The current Form 4 relates to the vesting and issuance of 40% of the PSU shares tied to the company reporting $2.5 billion in annual net product revenue under GAAP.