Acumen (ABOS) CMO receives 99,133 RSUs and 148,700 options

Rhea-AI Filing Summary

Acumen Pharmaceuticals Chief Medical Officer Eric Siemers reported new equity awards from the company. On January 16, 2026, he received 99,133 shares of Common Stock at a price of $0, described as a restricted stock unit award that vests in three equal annual installments starting one year after the grant date, subject to continued service. The filing also shows a grant of an employee stock option for 148,700 shares of Common Stock at an exercise price of $1.89 per share, vesting in 48 equal monthly installments and expiring on January 16, 2036. Following these grants, Siemers directly owns 258,597 shares of Common Stock and 148,700 stock options.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Siemers Eric

(Last) (First) (Middle)

C/O ACUMEN PHARMACEUTICALS, INC.

1210-1220 WASHINGTON STREET, SUITE 210

(Street)

NEWTON MA 02465

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Acumen Pharmaceuticals, Inc. [ ABOS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Medical Officer

3. Date of Earliest Transaction (Month/Day/Year)
01/16/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/16/2026		A		99,133(1)	A	$0	258,597	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	$1.89	01/16/2026		A		148,700		(2)	01/16/2036	Common Stock	148,700	$0	148,700	D

Explanation of Responses:

1. 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.

2. 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.

Remarks:

	/s/ Derek Meisner, Attorney-in-Fact	01/21/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Acumen Pharmaceuticals (ABOS) disclose in this Form 4?

The filing reports equity awards to Chief Medical Officer Eric Siemers, including new restricted stock units and stock options in Acumen Pharmaceuticals, Inc..

How many Acumen Pharmaceuticals (ABOS) shares did Eric Siemers acquire?

Eric Siemers acquired 99,133 shares of Common Stock at $0 as part of a restricted stock unit award, increasing his direct holdings to 258,597 shares after the transaction.

What stock options were granted to Eric Siemers at Acumen Pharmaceuticals (ABOS)?

He received an employee stock option covering 148,700 shares of Common Stock with an exercise price of $1.89 per share and an expiration date of January 16, 2036.

How do Eric Siemers' restricted stock units in Acumen Pharmaceuticals (ABOS) vest?

The 99,133 RSUs vest in three equal annual installments beginning one year after the grant date, subject to his continuous service through each vesting date.

What is the vesting schedule for Eric Siemers' stock options at Acumen Pharmaceuticals (ABOS)?

The 148,700 stock options vest in 48 equal monthly installments so that they are fully vested on the fourth anniversary of the grant date, assuming continued service.

Is Eric Siemers’ ownership in Acumen Pharmaceuticals (ABOS) direct or indirect?

The Form 4 indicates that both the Common Stock and the stock options are held with direct (D) ownership by Eric Siemers.