Acumen Pharmaceuticals (ABOS) legal chief sells shares in planned 10b5-1 trades

Rhea-AI Filing Summary

Acumen Pharmaceuticals Chief Legal Officer Derek M. Meisner reported three sales of common stock under pre-arranged Rule 10b5-1 trading plans. On January 21, 2026, he sold 2,247 shares at a weighted average price of $1.8083 per share through an automatic “sell to cover” transaction to satisfy tax withholding tied to vesting restricted stock units under a plan adopted on May 15, 2024. On January 22, 2026, he sold 1,054 shares at $1.84 per share, and on January 23, 2026, he sold 5,633 shares at a weighted average price of $1.9027 per share under a separate Rule 10b5-1 plan adopted on March 29, 2025. After these transactions, he directly owned 173,999 shares of Acumen Pharmaceuticals common stock.

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

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

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^*

Meisner Derek M

(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 Legal Officer & Corp Sec

3. Date of Earliest Transaction (Month/Day/Year)
01/21/2026

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	01/21/2026		S		2,247(1)	D	$1.8083(2)	180,686	D
Common Stock	01/22/2026		S		1,054(1)	D	$1.84	179,632	D
Common Stock	01/23/2026		S		5,633(3)	D	$1.9027(4)	173,999	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

Explanation of Responses:

1. 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 May 15, 2024.

2. 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.

3. Represents the number of shares sold by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 29, 2025.

4. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.8800 to $1.9400. 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.

Remarks:

	/s/ Derek Meisner	01/23/2026
	** 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

Who is the insider in Acumen Pharmaceuticals (ABOS) latest Form 4 filing?

The insider is Derek M. Meisner, who serves as Chief Legal Officer & Corporate Secretary of Acumen Pharmaceuticals, Inc.

How many Acumen Pharmaceuticals (ABOS) shares did Derek Meisner sell in January 2026?

Across three transactions on January 21–23, 2026, Derek Meisner sold a total of 8,934 shares of Acumen Pharmaceuticals common stock at prices between $1.7600 and $1.9400 per share.

What prices were received in the reported Acumen Pharmaceuticals (ABOS) insider stock sales?

The Form 4 reports weighted average sale prices of $1.8083 per share on January 21, 2026, $1.84 per share on January 22, 2026, and $1.9027 per share on January 23, 2026, with actual trades executed in ranges between $1.7600 and $1.9400.

How many Acumen Pharmaceuticals (ABOS) shares does Derek Meisner own after these transactions?

Following the reported January 2026 sales, Derek Meisner directly beneficially owned 173,999 shares of Acumen Pharmaceuticals common stock.

Were the Acumen Pharmaceuticals (ABOS) insider sales part of Rule 10b5-1 trading plans?

Yes. The Form 4 states that the January 21, 2026 sale was an automatic “sell to cover” for tax withholding under a Rule 10b5-1 plan adopted on May 15, 2024, and the January 23, 2026 sale was made under a Rule 10b5-1 plan adopted on March 29, 2025.

Why did Derek Meisner sell some Acumen Pharmaceuticals (ABOS) shares on January 21, 2026?

The Form 4 notes that the 2,247 shares sold on January 21, 2026 were part of an automatic “sell to cover” transaction to satisfy tax withholding obligations related to vesting restricted stock units.