Eric Siemers - 16 Jan 2026 Form 4 Insider Report for Acumen Pharmaceuticals, Inc. (ABOS)

Reporting relationship: Chief Medical Officer
Issuer ticker: ABOS
Reported as of: 16 Jan 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 21 Jan 2026, 18:31:11 UTC
Prior SEC filing: 07 Jan 2026
Next SEC filing: 23 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 21 Jan 2026.

Key facts

This page summarizes Eric Siemers's Form 4 filing for Acumen Pharmaceuticals, Inc. (ABOS).
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 21 Jan 2026, 18:31.

Change

Previous filing in this sequence was filed on 07 Jan 2026.
Current net transaction value: $0.

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: 21 Jan 2026

Reported non-derivative transactions

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

ABOS transaction

Common Stock

Award

Transaction value: $0
Shares: +99,133
Change %: +62%
Price: $0.000000
Shares after: 258,597
Date: 16 Jan 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

ABOS transaction Derivative

Employee Stock Option (right to buy)

Award

Transaction value: $0
Shares: +148,700
Change %
Price: $0.000000
Shares after: 148,700
Date: 16 Jan 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 148,700
Exercise price: $1.89
Footnotes: F2

^* 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 a restricted stock unit ("RSU") award. Each RSU represents a contingent right to receive one share of the Issuer's Common Stock. The RSUs will vest in three equal annual installments commencing one year after the grant date, subject to the Reporting Person's continuous service through each such vesting date.

Footnote F2

The shares subject to the option will vest in 48 equal monthly installments such that the option is fully vested on the fourth anniversary of the date of grant, subject to the Reporting Person's continuous service through each such vesting date.