Eric Siemers - 21 Jan 2026 Form 4 Insider Report for Acumen Pharmaceuticals, Inc. (ABOS)

Reporting relationship: Chief Medical Officer
Issuer ticker: ABOS
Reported as of: 21 Jan 2026
Net transaction value: -$5,833
SEC form: 4
Accepted by SEC: 23 Jan 2026, 18:12:03 UTC
Prior SEC filing: 21 Jan 2026
Source filing: View source filing
Reporting owner signature: /s/ Derek Meisner, Attorney-in-Fact

Key filing fact

Eric Siemers filed Form 4 for Acumen Pharmaceuticals, Inc. (ABOS) on 23 Jan 2026.

Key facts

This page summarizes Eric Siemers's Form 4 filing for Acumen Pharmaceuticals, Inc. (ABOS).
2 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 23 Jan 2026, 18:12.

Change

Previous filing in this sequence was filed on 21 Jan 2026.
Current net transaction value: -$5,833.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001866239 Primary reporting owner

Siemers Eric

Relationship: Chief Medical Officer
Address: C/O ACUMEN PHARMACEUTICALS, INC., 1210-1220 WASHINGTON STREET, SUITE 210, NEWTON
Signature: /s/ Derek Meisner, Attorney-in-Fact
Signature date: 23 Jan 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ABOS transaction

Common Stock

Sale

Transaction value: $4,204
Shares: -2,331
Change %: -0.9%
Price: $1.80
Shares after: 256,266
Date: 21 Jan 2026
Ownership: Direct
Footnotes: F1, F2

ABOS transaction

Common Stock

Sale

Transaction value: $1,629
Shares: -895
Change %: -0.35%
Price: $1.82
Shares after: 255,371
Date: 22 Jan 2026
Ownership: Direct
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

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 September 3, 2024.

Footnote F2

The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.7600 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.