ALNYLAM PHARMACEUTICALS INC

Adoption of 10b5-1 Trading Plans by Our Officers and Directors

During our fiscal quarter ended December 31, 2024, one of our directors entered into a written plan for the sale of our securities that is intended to satisfy the conditions specified in Rule 10b5-1(c) under the Exchange Act for an affirmative defense against liability for trading in securities on the basis of material nonpublic information. We refer to this written plan as a “Rule 10b5-1 trading plan.” We describe the material terms of the Rule 10b5-1 trading plan below.

Michael W. Bonney, Director

On November 12, 2024, Michael W. Bonney, a member of our board of directors, entered into a Rule 10b5-1 trading plan that provides that Mr. Bonney, acting through a broker, may sell up to an aggregate of 22,500 shares of our common stock received upon the exercise of options granted to Mr. Bonney as director compensation, subject to adjustments for stock splits, stock combinations, stock dividends and other similar changes to our common stock. Sales of shares under the plan may only occur if the market price of our common stock is above specified prices from February 12, 2025 to June 3, 2026. The plan is scheduled to terminate on June 3, 2026, subject to earlier termination upon the sale of all shares subject to the plan, upon termination by Mr. Bonney or the broker, or as otherwise provided in the plan.