Alnylam (NASDAQ: ALNY) CEO converts 5,921 RSUs into common stock

Rhea-AI Filing Summary

ALNYLAM PHARMACEUTICALS, INC. Chief Executive Officer Yvonne Greenstreet reported the vesting and conversion of 5,921 restricted stock units into an equal number of common shares on February 27, 2026. These RSUs were part of a 17,763-unit grant from February 27, 2023 that vests in three equal annual installments.

Following this derivative exercise, her directly held common stock increased to 91,583 shares. She also has 407 common shares held indirectly in a managed account. The transaction reflects equity compensation vesting, not an open-market purchase or sale.

Insider Trade Summary

5,921 shares exercised/converted

Mixed 3 txns

Insider Greenstreet Yvonne

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	5,921	$0.00	--
Exercise	Common Stock	5,921	$0.00	--
holding	Common Stock	--	--	--

Holdings After Transaction: Restricted Stock Units — 0 shares (Direct); Common Stock — 91,583 shares (Direct); Common Stock — 407 shares (Indirect, by Managed Account)

Footnotes (1)

1. 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. These shares are represented by restricted stock units (RSUs) granted under the Amended and Restated 2018 Stock Incentive Plan. Each RSU represents a contingent right to receive one share of common stock. On February 27, 2023, the reporting person was granted 17,763 restricted stock units that vest ratably on each of the first, second and third anniversaries of the Grant Date. On February 27, 2026, the third and final tranche of restricted stock units from the February 27, 2023 grant vested and was released, as reported on this Form 4. The restricted stock units vest ratably in three installments, with one third vesting on each of the first, second and third anniversaries of the grant date.

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^*

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)
02/27/2026

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	02/27/2026		M		5,921	A	$0.0	91,583	D
Common Stock								407	I	by Managed Account(1)

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 Units	(2)	02/27/2026		M			5,921	(3)	(4)	Common Stock	5,921	$0.0	0	D

Explanation of Responses:

1. 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.

2. These shares are represented by restricted stock units (RSUs) granted under the Amended and Restated 2018 Stock Incentive Plan. Each RSU represents a contingent right to receive one share of common stock.

3. On February 27, 2023, the reporting person was granted 17,763 restricted stock units that vest ratably on each of the first, second and third anniversaries of the Grant Date. On February 27, 2026, the third and final tranche of restricted stock units from the February 27, 2023 grant vested and was released, as reported on this Form 4.

4. The restricted stock units vest ratably in three installments, with one third vesting on each of the first, second and third anniversaries of the grant date.

	By: Brett Budzinski, Attorney-in-Fact For: Yvonne Greenstreet	03/02/2026
	** 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 transaction did Alnylam (ALNY) CEO Yvonne Greenstreet report?

Yvonne Greenstreet reported the vesting and conversion of 5,921 restricted stock units into common stock. These RSUs were part of a 17,763-unit grant that vests over three years, reflecting scheduled equity compensation rather than an open-market trade.

How many Alnylam (ALNY) shares does the CEO hold after this Form 4?

After the reported transactions, Yvonne Greenstreet directly holds 91,583 Alnylam common shares. In addition, 407 common shares are held indirectly in a managed account, giving insight into both her direct and indirect equity exposure to the company.

What is the origin of the 5,921 RSUs reported by Alnylam (ALNY) CEO?

The 5,921 RSUs come from a 17,763-unit award granted on February 27, 2023. That grant vests in three equal annual installments, and the February 27, 2026 tranche represented the third and final portion becoming common stock.

Was cash paid in the Alnylam (ALNY) CEO’s 5,921-share RSU conversion?

The RSU conversion shows a price per share of 0.0000, indicating no cash purchase on the market. It reflects the automatic release of vested stock units granted as compensation under Alnylam’s Amended and Restated 2018 Stock Incentive Plan.

Are the reported Alnylam (ALNY) CEO transactions open-market buys or sells?

The filing classifies the Form 4 entries with code M, indicating exercise or conversion of derivative securities. This means RSUs vested into common stock, rather than open-market buying or selling of Alnylam shares by the Chief Executive Officer.