[Form 4] Alnylam Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Tolga Tanguler, EVP and Chief Commercial Officer of Alnylam Pharmaceuticals (ALNY), reported multiple open-market sales of Company common stock on 08/29/2025 executed under a Rule 10b5-1 trading plan. The filings show six separate sale transactions totaling 3,474 shares, with weighted average sale prices reported in ranges from approximately $445.32 to $452.54 per share. Following these transactions the reporting person’s beneficial ownership is reported as 25,992 shares. The Form 4 was signed by an attorney-in-fact on behalf of Mr. Tanguler and includes explanatory notes that each reported price is a weighted average of multiple executions within the stated ranges.

Insights

Securities Analyst

TL;DR: Executive sold 3,474 ALNY shares under a pre-established 10b5-1 plan; reported ending ownership 25,992 shares.

The Form 4 discloses routine insider sales by the EVP, executed on 08/29/2025 under a Rule 10b5-1(c) plan adopted May 27, 2025. Six sale lots are reported with weighted average price ranges between roughly $445.32 and $452.54. Such scheduled-plan sales limit managerial inference about contemporaneous company-specific news, but they do reduce the executive’s direct stake to 25,992 shares. The filing is procedural and contains full explanatory notes about weighted-average pricing for multiple executions.

Corporate Governance Expert

TL;DR: Sales were made under an established 10b5-1 plan, indicating pre-planned disposition rather than ad hoc trading.

The disclosure clearly cites a 10b5-1(c) trading plan adopted May 27, 2025, which provides an affirmative defense to allegations of trading on material nonpublic information when properly structured. The Form 4 documents multiple sale transactions on a single date with explicit weighted-average price ranges and reports the post-transaction beneficial ownership. From a governance standpoint, the filing meets typical transparency standards for insider transactions.

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^*

Tanguler Tolga

(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)
	EVP, Chief Commercial Officer

3. Date of Earliest Transaction (Month/Day/Year)
08/29/2025

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	08/29/2025		S(1)		195	D	$445.53(2)	29,271	D
Common Stock	08/29/2025		S(1)		899	D	$446.98(3)	28,372	D
Common Stock	08/29/2025		S(1)		1,289	D	$448.05(4)	27,083	D
Common Stock	08/29/2025		S(1)		681	D	$449.54(5)	26,402	D
Common Stock	08/29/2025		S(1)		266	D	$451.52(6)	26,136	D
Common Stock	08/29/2025		S(1)		144	D	$452.49(7)	25,992	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

Explanation of Responses:

1. This transaction was made pursuant to a Rule 10b5-1(c) trading plan adopted by the Reporting Person on May 27, 2025.

2. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $445.32 to $445.79. 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.

3. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $446.34 to $447.34. 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 $447.59 to $448.58. 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 $449.07 to $449.98. 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 $451.21 to $451.68. 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.

7. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $452.22 to $452.54. 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.

	By: Brett Budzinski, Attorney-in-Fact For: Tolga Tanguler	09/02/2025
	** 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 did Tolga Tanguler (ALNY) report on the Form 4?

Tolga Tanguler reported six open-market sales on 08/29/2025 totaling 3,474 shares, with post-transaction beneficial ownership of 25,992 shares.

Were the sales by the ALNY executive part of a pre-established plan?

Yes. The transactions were made pursuant to a Rule 10b5-1(c) trading plan adopted on May 27, 2025.

What price information is reported for the ALNY sales?

The Form 4 reports weighted average sale prices with execution ranges approximately from $445.32 to $452.54 per share, with explanatory notes for each lot.

When were the transactions executed according to the filing?

All reported sales were executed on 08/29/2025.

Who signed the Form 4 for Tolga Tanguler?

The Form 4 was signed by Brett Budzinski, Attorney-in-Fact, on behalf of Tolga Tanguler on 09/02/2025.