X0508 4 2026-01-08 0 0001576885 Acumen Pharmaceuticals, Inc. ABOS 0001865136 OConnell Daniel Joseph C/O ACUMEN PHARMACEUTICALS, INC. 1210-1220 WASHINGTON STREET, SUITE 210 NEWTON MA 02465 1 1 0 0 Chief Executive Officer 0 Common Stock 2026-01-08 4 S 0 8143 1.8194 D 611839 D Common Stock 2026-01-09 4 S 0 12941 1.7643 D 598898 D Common Stock 2026-01-12 4 S 0 5388 1.7273 D 593510 D Represents the number of shares sold by the Reporting Person through an automatic "sell to cover" transaction to satisfy tax withholding obligations in connection with the vesting of restricted stock units pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 27, 2025. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.7200 to $1.8700. Upon request, the Reporting Person will provide to the staff of the Securities and Exchange Commission, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.7100 to $1.8100. Upon request, the Reporting Person will provide to the staff of the Securities and Exchange Commission, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.6700 to $1.8400. Upon request, the Reporting Person will provide to the staff of the Securities and Exchange Commission, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. /s/ Derek Meisner, Attorney-in-Fact 2026-01-12