John Cox - 16 Jul 2025 Form 4 Insider Report for Dyne Therapeutics, Inc. (DYN)

Role: CEO & President, Director
Signature: /s/ Ron Caponigro, Attorney-in-Fact
Issuer symbol: DYN
Transactions as of: 16 Jul 2025
Transactions value $: $0
Form type: 4
Filing time: 18 Jul 2025, 17:19:53 UTC
Previous filing: 15 Jul 2025
Next filing: 09 Sep 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Cox John	CEO & President, Director	C/O DYNE THERAPEUTICS, INC., 1560 TRAPELO ROAD, WALTHAM	/s/ Ron Caponigro, Attorney-in-Fact	18 Jul 2025	0001498428

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	DYN	Stock option (right to buy)	Award	$0	+197K		$0.00	197K	16 Jul 2025	Common Stock	197K	$9.33	Direct	F1

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

Explanation of Responses:

Id	Content
F1	This option was granted on July 16, 2025 (the "Grant Date"). The shares underlying the option are scheduled to vest over three years, with 50% of the shares underlying the grant vesting 18 months after the Grant Date and with the balance of the shares underlying the grant vesting in equal quarterly installments thereafter; provided that such option shall not be exercisable unless and until (i) the average closing price of the common stock on the Nasdaq Global Select Market over a 20 consecutive trading day period equals or exceeds $20.00 per share at any time during the three-year period following the Grant Date (the "Performance Period") or (ii) a Change in Control (as defined in the Issuer's Amended and Restated Executive Severance and Change in Control Benefits Plan) is consummated during the Performance Period pursuant to which a third party acquires the common stock for a price per share that the Board of Directors of the Issuer determines equals or exceeds $20.00 per share.

Content

This option was granted on July 16, 2025 (the "Grant Date"). The shares underlying the option are scheduled to vest over three years, with 50% of the shares underlying the grant vesting 18 months after the Grant Date and with the balance of the shares underlying the grant vesting in equal quarterly installments thereafter; provided that such option shall not be exercisable unless and until (i) the average closing price of the common stock on the Nasdaq Global Select Market over a 20 consecutive trading day period equals or exceeds $20.00 per share at any time during the three-year period following the Grant Date (the "Performance Period") or (ii) a Change in Control (as defined in the Issuer's Amended and Restated Executive Severance and Change in Control Benefits Plan) is consummated during the Performance Period pursuant to which a third party acquires the common stock for a price per share that the Board of Directors of the Issuer determines equals or exceeds $20.00 per share.