Acumen Pharmaceuticals, Inc.

From time to time, our officers (as defined in Rule 16a-1(f)) and directors may enter into Rule 10b5-1 ornon-Rule 10b5-1 trading plans (as each such term is defined in Item 408 of Regulation S-K). The trading plans are intended to satisfy the affirmative defense in Rule 10b5-1(c). During the three months ended March 31, 2025, our officers and directors took the following actions with respect to 10b5-1 trading plans:

On April 1, 2025, Derek Meisner, our Chief Legal Officer, terminated a Rule 10b5-1 plan that had been adopted on May 15, 2024 that provided that Mr. Meisner, acting through a broker, could sell (1) up to 108,867 shares of our common stock received upon the settlement of RSU awards granted to Mr. Meisner as equity incentive compensation, which sales were eligible to occur from January 3, 2025 to July 31, 2028; and (2)482,800 shares of our common stock received upon the exercise of option awards granted to Mr. Meisner as equity incentive compensation, which sales were eligible to occur from September 17, 2024 to July 31, 2028.

On March 31, 2025, Mr. Meisner entered into a Rule 10b5-1 trading plan that provides that Mr. Meisner, acting through a broker, may sell the number of shares of common stock sufficient to cover the taxes, commissions and any fees associated with the vesting of up to 66,800 RSU awards granted to Mr. Meisner as equity compensation, which sales may occur from

January 7, 2026 to January 31, 2028. On March 31, 2025, Mr. Meisner also entered into a separate Rule 10b5-1 trading plan that provides that Mr. Meisner, acting through a broker, may sell up to (1)24,727 shares of common stock, which sales may occur from January 6, 2026 through January 9, 2029; (2)583,100 shares of common stock received upon the exercise of option awards granted to Mr. Meisner as equity incentive compensation, which sales may occur from July 28, 2025 through January 9, 2029; and (3)136,400 shares of common stock received upon the vesting of RSU awards granted to Mr. Meisner as equity incentive compensation, which sales may occur from January 6, 2026 to January 9, 2029.