Acumen Pharmaceuticals (ABOS) COO sells shares for taxes in 10b5-1 tax sale

Rhea-AI Filing Summary

Acumen Pharmaceuticals, Inc. reported an insider stock sale by its Chief Operating Officer, Barton Russell. On January 8, 2026, he sold 3,530 shares of common stock in a transaction coded as a sale. The filing explains this was an automatic “sell to cover” to satisfy tax withholding obligations tied to the vesting of restricted stock units under a Rule 10b5-1 trading plan he adopted on June 25, 2025. The shares were sold at a weighted average price of $1.8588 per share, in multiple trades between $1.8000 and $1.9500. After this transaction, he continued to beneficially own 123,269 shares, all held directly.

Insider Trade Summary

Net Seller: 3,530 shares ($6,562)

Net Sell 1 txn

Insider Barton Russell

Role Chief Operating Officer

Sold 3,530 shs ($7K)

Type	Security	Shares	Price	Value
Sale	Common Stock	3,530	$1.8588	$7K

Holdings After Transaction: Common Stock — 123,269 shares (Direct)

Footnotes (1)

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 June 25, 2025. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.8000 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.

Form 4 Insider Transactions: What Each Field Means →

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
Estimated average burden
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^*

Barton Russell

(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 Operating Officer

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		3,530(1)	D	$1.8588(2)	123,269	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 June 25, 2025.

2. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.8000 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.

Remarks:

	/s/ Derek Meisner, Attorney-in-Fact	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 transaction did Acumen Pharmaceuticals (ABOS) disclose in this Form 4?

The company reported that its Chief Operating Officer, Barton Russell, sold 3,530 shares of Acumen Pharmaceuticals common stock on January 8, 2026, in a transaction coded as a sale.

Why did Acumen Pharmaceuticals COO Barton Russell sell 3,530 shares?

The filing states the 3,530 shares were sold through an automatic “sell to cover” transaction to satisfy tax withholding obligations related to the vesting of restricted stock units under a Rule 10b5-1 trading plan.

What was the sale price for the Acumen Pharmaceuticals shares in this insider trade?

The sale price is reported as a weighted average of $1.8588 per share, with individual trades executed at prices ranging from $1.8000 to $1.9500.

How many Acumen Pharmaceuticals shares does Barton Russell own after this Form 4 transaction?

After the reported sale, Barton Russell beneficially owned 123,269 shares of Acumen Pharmaceuticals common stock, held in direct ownership.

Was the Acumen Pharmaceuticals insider sale made under a Rule 10b5-1 plan?

Yes. The filing notes the sale was executed under a Rule 10b5-1 trading plan that Barton Russell adopted on June 25, 2025, and the form allows indication that the transaction was made pursuant to such a plan.

Who is the insider involved in this Acumen Pharmaceuticals (ABOS) Form 4 filing and what is their role?

The reporting person is Barton Russell, who is identified as an officer of Acumen Pharmaceuticals, serving as the company’s Chief Operating Officer, and is not listed as a director or 10% owner.