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 June 30, 2025, our officers and directors took the following actions with respect to 10b5-1 trading plans:

On June 25, 2025, Russell Barton, our Chief Operating Officer, entered into a Rule 10b5-1 trading plan that provides that Mr. Barton, 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 49,800 RSU awards granted to Mr. Barton as equity compensation, which sales may occur from January 7, 2026 to December 29, 2028.

On June 27, 2025, Daniel O’Connell, our Chief Executive Officer, entered into a Rule 10b5-1 trading plan that provides that Mr. O’Connell, 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 225,400 RSU awards granted to Mr. O’Connell as equity compensation, which sales may occur from January 8, 2026 to December 29, 2028.

On June 30, 2025, Matt Zuga, our Chief Financial Officer and Chief Business Officer, entered into a Rule 10b5-1 trading plan that provides that Mr. Zuga, 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. Zuga as equity compensation, which sales may occur from January 7, 2026 to December 29, 2028.