Dyne Therapeutics (DYN) CMO auto-sells shares to cover RSU tax obligations

Rhea-AI Filing Summary

Dyne Therapeutics, Inc. Chief Medical Officer Douglas Kerr reported an automatic sale of 904 shares of common stock on March 5, 2026 at $14.90 per share. The shares were sold to satisfy tax withholding obligations tied to the vesting of restricted stock units granted on December 4, 2024, under a pre-arranged Rule 10b5-1 "binding contract," so the transaction was not a discretionary trade. Following this sale, he beneficially owned 171,606 shares, including 153,625 unvested RSUs.

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).

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^*

Kerr Douglas

(Last) (First) (Middle)

C/O DYNE THERAPEUTICS, INC.

1560 TRAPELO ROAD

(Street)

WALTHAM MA 02451

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Dyne Therapeutics, Inc. [ DYN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

3. Date of Earliest Transaction (Month/Day/Year)
03/05/2026

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	03/05/2026		S(1)		904	D	$14.9	171,606(2)	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 shares automatically sold by the Reporting Person to satisfy tax withholding obligations in connection with the vesting of restricted stock units granted to the Reporting Person on December 4, 2024. The automatic sale of the Reporting Person's shares is provided for in a restricted stock unit agreement constituting a "binding contract" consistent with the affirmative defense to liability under Rule 10b5-1 and the sale does not represent a discretionary trade by the Reporting Person.

2. Includes 153,625 unvested RSUs.

	/s/ Ron Caponigro, Attorney-in-Fact	03/06/2026
	** 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 did Dyne Therapeutics (DYN) CMO Douglas Kerr report in this Form 4?

Douglas Kerr reported an automatic sale of Dyne Therapeutics shares. He disclosed selling 904 shares of common stock at $14.90 per share in a transaction designed to cover tax withholding obligations from vesting restricted stock units granted on December 4, 2024.

How many Dyne Therapeutics (DYN) shares did Douglas Kerr sell and at what price?

Douglas Kerr sold 904 Dyne Therapeutics common shares at $14.90 each. The transaction was an open-market sale documented as satisfying tax withholding obligations from vesting restricted stock units, rather than a discretionary decision to reduce his investment in the company.

Why were Douglas Kerr’s Dyne Therapeutics (DYN) shares sold in this transaction?

The sale was to satisfy tax withholding obligations on vesting RSUs. Footnotes explain the 904 shares were automatically sold under a restricted stock unit agreement as part of a Rule 10b5-1 "binding contract," so the transaction did not represent a discretionary trade by Kerr.

Was Douglas Kerr’s Dyne Therapeutics (DYN) share sale a discretionary trade?

No, the sale was not a discretionary trade by Douglas Kerr. The filing states the 904 shares were automatically sold under a restricted stock unit agreement constituting a Rule 10b5-1 "binding contract" specifically to cover tax withholding obligations from RSU vesting.

How many Dyne Therapeutics (DYN) shares does Douglas Kerr hold after this Form 4 transaction?

After the sale, Douglas Kerr beneficially owned 171,606 shares. The footnotes further clarify that this amount includes 153,625 unvested restricted stock units, indicating a substantial portion of his reported holdings remains subject to future vesting conditions.

What are the restricted stock units (RSUs) mentioned in Douglas Kerr’s Dyne Therapeutics (DYN) filing?

The RSUs are equity awards that vest over time for Douglas Kerr. The filing notes his holdings include 153,625 unvested RSUs, and the automatic sale of 904 shares occurred to cover tax withholding obligations arising when some of these restricted stock units vested.