Acumen Pharmaceuticals (ABOS) CEO logs Rule 10b5-1 tax sales Jan 2026

Rhea-AI Filing Summary

Acumen Pharmaceuticals, Inc. chief executive Daniel Joseph O’Connell reported automatic sales of company common stock to cover taxes on equity awards. On January 5, 6, and 7, 2026, he sold 4,649, 5,102, and 37,755 shares of Acumen common stock, respectively, at weighted average prices of $1.971, $1.9662, and $1.986 per share. The filing states these were sell-to-cover transactions to satisfy tax withholding obligations tied to the vesting of restricted stock units under a Rule 10b5-1 trading plan adopted on June 24, 2024. Following the latest reported sale, O’Connell beneficially owned 619,982 shares of Acumen common stock directly.

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^*

OConnell Daniel Joseph

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
01/05/2026

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	01/05/2026		S		4,649(1)	D	$1.971(2)	662,839	D
Common Stock	01/06/2026		S		5,102(1)	D	$1.9662(3)	657,737	D
Common Stock	01/07/2026		S		37,755(1)	D	$1.986(4)	619,982	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 24, 2024.

2. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.9000 to $2.0600. 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. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.9400 to $2.0000. 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.

4. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $1.9500 to $2.0300. 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	01/07/2026
	** 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) report on this Form 4?

The Form 4 reports that Daniel Joseph O’Connell, Acumen’s chief executive officer and a director, sold shares of Acumen Pharmaceuticals, Inc. common stock in three transactions on January 5, 6, and 7, 2026.

How many Acumen (ABOS) shares did the CEO sell and at what prices?

The CEO sold 4,649 shares at $1.971 on January 5, 5,102 shares at $1.9662 on January 6, and 37,755 shares at $1.986 on January 7, 2026. Each reported price is a weighted average sales price.

Why were these Acumen Pharmaceuticals CEO share sales executed?

According to the footnotes, the sales represent automatic sell-to-cover transactions to satisfy tax withholding obligations in connection with the vesting of restricted stock units under a Rule 10b5-1 trading plan adopted on June 24, 2024.

How many Acumen (ABOS) shares does the CEO own after these transactions?

After the reported January 7, 2026 transaction, Daniel Joseph O’Connell beneficially owned 619,982 shares of Acumen Pharmaceuticals, Inc. common stock, held directly.

Were the reported Acumen CEO stock sales part of a Rule 10b5-1 plan?

Yes. The filing explains that the transactions were executed under a Rule 10b5-1 trading plan adopted by the reporting person on June 24, 2024, in connection with tax withholding on restricted stock unit vesting.

Do the Form 4 footnotes provide details on Acumen (ABOS) share price ranges for these sales?

Yes. For each date, the footnotes state that the reported price is a weighted average and that shares were sold in multiple trades within ranges of $1.90 to $2.06, $1.94 to $2.00, and $1.95 to $2.03. The reporting person will provide the number of shares sold at each separate price upon request.