Douglas Kerr - Dec 5, 2025 Form 4 Insider Report for Dyne Therapeutics, Inc. (DYN)

Role
Chief Medical Officer
Signature
/s/ Ron Caponigro, Attorney-in-Fact
Stock symbol
DYN
Transactions as of
Dec 5, 2025
Transactions value $
-$18,234
Form type
4
Date filed
12/5/2025, 04:09 PM
Previous filing
Sep 8, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Kerr Douglas Chief Medical Officer C/O DYNE THERAPEUTICS, INC., 1560 TRAPELO ROAD, WALTHAM /s/ Ron Caponigro, Attorney-in-Fact 2025-12-05 0001814189

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction DYN Common Stock Sale -$18.2K -880 -1% $20.72 87.5K Dec 5, 2025 Direct F1, F2, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 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.
F2 The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices within the range of $20.58 to $20.96, 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.
F3 Includes 71,625 unvested RSUs.