Acumen (NASDAQ: ABOS) legal chief sells stock under 10b5-1 plan

Rhea-AI Filing Summary

Acumen Pharmaceuticals Chief Legal Officer Derek Meisner reported several sales of Acumen common stock under a pre-arranged Rule 10b5-1 trading plan. On January 8, 2026, he sold 6,819 shares at a weighted average price of $1.8154 in an automatic “sell to cover” transaction to satisfy tax withholding on vesting restricted stock units, and 30,092 shares at a weighted average price of $1.8233 under the same plan.

He later sold 5,200 shares on January 9, 2026 at a weighted average price of $1.7633, and 8,548 shares on January 12, 2026 at a weighted average price of $1.7148. After these transactions, Meisner directly held 83,800 shares of Acumen 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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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)
01/08/2026

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	01/08/2026		S		6,819(1)	D	$1.8154(2)	127,640	D
Common Stock	01/08/2026		S		30,092(3)	D	$1.8233(2)	97,548	D
Common Stock	01/09/2026		S		5,200(3)	D	$1.7633(4)	92,348	D
Common Stock	01/12/2026		S		8,548(3)	D	$1.7148(5)	83,800	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 March 29, 2025.

2. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.7200 to $1.9500. 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 $1.7100 to $1.8150. 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.

5. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.6700 to $1.8400. 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	01/12/2026
	** 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 insider activity did Acumen Pharmaceuticals (ABOS) report for Derek Meisner?

Acumen’s Chief Legal Officer, Derek Meisner, reported multiple sales of common stock in January 2026 under a Rule 10b5-1 trading plan, including a “sell to cover” for tax withholding on vested restricted stock units.

How many Acumen (ABOS) shares did Derek Meisner sell on January 8, 2026?

On January 8, 2026, Derek Meisner sold 6,819 shares at a weighted average price of $1.8154 in a sell-to-cover tax transaction and 30,092 shares at a weighted average price of $1.8233, both in Acumen common stock.

What additional Acumen (ABOS) stock sales did Derek Meisner report after January 8, 2026?

Meisner sold 5,200 shares of Acumen common stock on January 9, 2026 at a weighted average price of $1.7633, and 8,548 shares on January 12, 2026 at a weighted average price of $1.7148.

How many Acumen (ABOS) shares does Derek Meisner hold after these Form 4 transactions?

Following the reported January 2026 transactions, Derek Meisner directly beneficially owned 83,800 shares of Acumen Pharmaceuticals common stock.

Were Derek Meisner’s Acumen (ABOS) stock sales under a Rule 10b5-1 trading plan?

Yes. The filing states that the sales, including the sell-to-cover tax transaction, were made pursuant to a Rule 10b5-1 trading plan adopted by Derek Meisner on March 29, 2025.

What do the weighted average prices in Derek Meisner’s Acumen (ABOS) sales represent?

The reported prices, such as $1.8154, $1.8233, $1.7633, and $1.7148, are weighted average sales prices for multiple trades within price ranges disclosed in the footnotes.