RA CAPITAL MANAGEMENT, L.P. - 16 Mar 2026 Form 4 Insider Report for Acumen Pharmaceuticals, Inc. (ABOS)

Role
Director, 10%+ Owner
Signature
/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.
Issuer symbol
ABOS
Transactions as of
16 Mar 2026
Net transactions value
$0
Form type
4
Filing time
18 Mar 2026, 16:15:17 UTC
Previous filing
02 Mar 2026
SEC
View on sec.gov

Reporting Owners (5)

Name Relationship Address Signature Signature date CIK
RA CAPITAL MANAGEMENT, L.P. Director, 10%+ Owner 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 18 Mar 2026 0001346824
RA Capital Healthcare Fund LP Director, 10%+ Owner 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P. 18 Mar 2026 0001315082
RA Capital Nexus Fund II, L.P. Director 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC, the General Partner of RA Capital Nexus Fund II, L.P. 18 Mar 2026 0001825376
Kolchinsky Peter Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, individually 18 Mar 2026 0001384859
Shah Rajeev M. Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Rajeev Shah, individually 18 Mar 2026 0001619841

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction ABOS Common Stock Award +6,060,606 +46% $3.30* 19,103,785 16 Mar 2026 See footnotes F1, F2
holding ABOS Common Stock 1,300,034 16 Mar 2026 See footnotes F2, F3
holding ABOS Common Stock 588,850 16 Mar 2026 See footnotes F2, F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").
F2 RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, RA Capital Nexus Fund II, L.P. (the "Nexus Fund II") and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund II, Dr. Kolchinsky, and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.
F3 Held directly by the Nexus Fund II.
F4 Held directly by the Account.

Remarks:

Laura Stoppel, a Principal of the Adviser, serves on the Issuer's board of directors.