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).

1. Name and Address of Reporting Person* Atlas Venture Opportunity Fund I, L.P. (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (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 X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 03/01/2024
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X 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	03/01/2024		S(1)		29,435	D	$30.05(2)	1,458,691	D(3)
Common Stock	03/01/2024		S(4)		17,099	D	$30.05(2)	847,388	I	See footnote(5)

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

1. Name and Address of Reporting Person* Atlas Venture Opportunity Fund I, L.P. (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Atlas Venture Associates Opportunity I, L.P. (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Atlas Venture Associates Opportunity I, LLC (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Atlas Venture Opportunity Fund II, L.P. (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Atlas Venture Associates Opportunity II, LP (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Atlas Venture Associates Opportunity II, LLC (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by Atlas Venture Opportunity Fund I, L.P. on January 10, 2024.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $29.95 to $30.20 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

3. The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("AVOF I"). The general partner of AVOF I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by AVOF I, except to the extent of its pecuniary interest therein, if any.

4. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by Atlas Venture Opportunity Fund II, L.P. on January 10, 2024.

5. The shares are owned directly by Atlas Venture Opportunity Fund II, L.P. ("AVOF II"). Atlas Venture Associates Opportunity II, L.P. ("AVAO II LP") is the general partner of AVOF II. Atlas Venture Associates Opportunity II, LLC ("AVAO II LLC") is the general partner of AVAO II LP. Each of AVAO II LP and AVAO II LLC disclaims Section 16 beneficial ownership of the securities held by AVOF II, except to the extent of its pecuniary interest therein, if any.

	Atlas Venture Opportunity Fund I, L.P., By: Atlas Venture Associates Opportunity I, L.P., its general partner, By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: /s/ Ommer Chohan, Chief Financial Officer	03/05/2024
	Atlas Venture Associates Opportunity I, L.P. By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: /s/ Ommer Chohan, Chief Financial Officer	03/05/2024
	Atlas Venture Associates Opportunity I, LLC, By: /s/ Ommer Chohan, Chief Financial Officer	03/05/2024
	Atlas Venture Opportunity Fund II, L.P., By: Atlas Venture Associates Opportunity II, L.P., its general partner, By: Atlas Venture Associates Opportunity II, LLC, its general partner, By: /s/ Ommer Chohan, Chief Financial Officer	03/05/2024
	Atlas Venture Associates Opportunity II, L.P., By: Atlas Venture Associates Opportunity II, LLC, its general partner, By: /s/ Ommer Chohan, Chief Financial Officer	03/05/2024
	Atlas Venture Associates Opportunity II, LLC, By: /s/ Ommer Chohan, Chief Financial Officer	03/05/2024
	** Signature of Reporting Person	Date
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