X0609 4 2026-09-19 0001178670 ALNYLAM PHARMACEUTICALS, INC. ALNY 0001446125 Greenstreet Yvonne false 675 WEST KENDALL STREET CAMBRIDGE MA 02142 1 1 Chief Executive Officer 0 Common Stock 2026-09-19 4 A 0 107 0 A 95802 D Common Stock 407 I by Managed Account On February 23, 2016, the People, Culture, and Compensation Committee of the issuer approved the issuance of shares of Company common stock having an aggregate value of USD $50,000 to each employee who completes 10 consecutive years of employment. The shares issued and reported here on Form 4, net of the minimum statutory tax liability, were issued to the reporting person in recognition of 10 years of continuous employment on September 19, 2026. Reflects shares of ALNY common stock acquired by the reporting person under the ALNY 401(k) plan as a result of the ALNY 401(k) matching contribution program. Brett Budzinski, Attorney-in-Fact For: Yvonne Greenstreet 2026-09-22