Acumen Pharmaceuticals (ABOS) CLO exercises 17,756 options and sells stock

Rhea-AI Filing Summary

Acumen Pharmaceuticals Chief Legal Officer Derek Meisner reported option exercises and related stock sales. On January 26 and 28, 2026, he exercised a total of 17,756 employee stock options at an exercise price of $1.85 per share, acquiring the same number of common shares.

On those same dates, he sold 17,756 common shares at weighted average prices of $3.0005 and $3.0016 per share under a pre-established Rule 10b5-1 trading plan. Following these transactions, he directly owned 173,999 common shares and retained vested and unvested stock options that vest in 48 equal monthly installments from the grant date.

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).

X

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)
01/26/2026

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	01/26/2026		M		15,085	A	$1.85	189,084	D
Common Stock	01/26/2026		S(1)		15,085	D	$3.0005(2)	173,999	D
Common Stock	01/28/2026		M		2,671	A	$1.85	176,670	D
Common Stock	01/28/2026		S(1)		2,671	D	$3.0016(2)	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
Employee Stock Option (right to buy)	$1.85	01/26/2026		M			15,085	(3)	01/06/2035	Common Stock	15,085	$0	85,215	D
Employee Stock Option (right to buy)	$1.85	01/28/2026		M			2,671	(3)	01/06/2035	Common Stock	2,671	$0	82,544	D

Explanation of Responses:

1. The reported sales occurred automatically 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 $3.0000 to $3.0100. 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 shares subject to the employee stock option vest in 48 equal monthly installments starting on the date the option was granted, such that the option will be 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	01/28/2026
	** 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 transactions did Acumen Pharmaceuticals (ABOS) report for Derek Meisner?

Derek Meisner exercised 17,756 employee stock options at $1.85 per share and sold the same number of Acumen Pharmaceuticals common shares around $3.00 per share. The transactions occurred on January 26, 2026 and January 28, 2026 and were reported on a Form 4 filing.

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

After the reported transactions, Derek Meisner directly owned 173,999 shares of Acumen Pharmaceuticals common stock. This reflects his remaining holdings following option exercises and same-day sales executed under his Rule 10b5-1 trading plan, as disclosed in the Form 4 filing.

Were the Acumen Pharmaceuticals (ABOS) insider sales pre-planned under a Rule 10b5-1 plan?

Yes. The filing states that the reported sales occurred automatically under a Rule 10b5-1 trading plan adopted by Derek Meisner on March 29, 2025. Such plans allow preset trading instructions, helping separate personal trading decisions from day-to-day corporate developments.

What prices were received for the Acumen Pharmaceuticals (ABOS) shares sold?

The Form 4 reports weighted average sale prices of $3.0005 and $3.0016 per share. Footnotes explain that the shares were sold in multiple trades between $3.0000 and $3.0100, and detailed trade breakdowns are available upon request from the reporting person.

What are the terms of Derek Meisner’s Acumen Pharmaceuticals (ABOS) stock options?

The employee stock options have an exercise price of $1.85 per share and expire on January 6, 2035. They vest in 48 equal monthly installments starting from the grant date, requiring his continuous service through each monthly vesting date to continue vesting.

What type of securities were involved in this Acumen Pharmaceuticals (ABOS) Form 4?

The filing covers both common stock and employee stock options to buy common stock. Options were exercised at $1.85 per share, creating common shares that were then partially sold on the open market at weighted average prices slightly above $3.00 per share.