Brian S. Posner - 06 Mar 2026 Form 4 Insider Report for Dyne Therapeutics, Inc. (DYN)

Role: Director
Signature: /s/ Ron Caponigro, Attorney-in-Fact
Issuer symbol: DYN
Transactions as of: 06 Mar 2026
Net transactions value: +$45,180
Form type: 4
Filing time: 10 Mar 2026, 17:33:53 UTC
Previous filing: 02 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Posner Brian S	Director	1560 TRAPELO ROAD, WALTHAM	/s/ Ron Caponigro, Attorney-in-Fact	10 Mar 2026	0001372455

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	DYN	Common Stock	Purchase	$45,180	+3,000	+35%	$15.06	11,500	06 Mar 2026	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices within the range of $14.96 to $15.12, inclusive. The Reporting Person undertakes 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 of this Form 4.

Content

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices within the range of $14.96 to $15.12, inclusive. The Reporting Person undertakes 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 of this Form 4.