Form 4: Dyne Therapeutics CEO Sells Shares to Cover Tax Obligations Following RSU Vesting

Dyne Therapeutics CEO John Cox sold 4,060 shares of common stock on June 5, 2025, at a weighted average price of $13.35 per share, to satisfy tax withholding obligations related to restricted stock unit vesting.

Summary

• John Cox, the CEO & President and a Director of Dyne Therapeutics, Inc. (DYN), reported a transaction on June 5, 2025.
• The transaction involved the sale of 4,060 shares of Dyne Therapeutics common stock.
• The shares were sold at a weighted average price of $13.35 per share, with individual sales prices ranging from $13.21 to $13.46.
• This sale was non-discretionary and automatically executed to satisfy tax withholding obligations associated with the vesting of restricted stock units (RSUs) granted on December 4, 2024.
• The transaction was made pursuant to a Rule 10b5-1(c) plan, indicating a pre-arranged sale.
• Following the reported transaction, John Cox directly beneficially owns 142,179 shares of common stock, which includes 127,138 unvested RSUs.
• Additionally, Mr. Cox indirectly beneficially owns 32,000 shares of common stock, held in four separate trusts (8,000 shares each) for the benefit of a child.

Sentiment

Score: 5

Explanation: The transaction is a non-discretionary sale to cover tax obligations from RSU vesting, which is a routine event and does not reflect a change in management's outlook or a discretionary decision to sell shares. Therefore, the sentiment is neutral.

Future Outlook

This Form 4 filing does not contain any forward-looking statements or guidance regarding the company's future outlook.

Management Comments

• The sale 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.

Industry Context

This Form 4 filing details a routine insider transaction for tax purposes and does not provide information relevant to broader industry trends or competitive analysis.

Related Party Transactions

• John Cox indirectly holds 32,000 shares of common stock (8,000 shares in each of four separate trusts) for the benefit of a child of the Reporting Person.

Stakeholder Impact

• Shareholders: Minimal direct impact as the transaction is a routine, non-discretionary sale for tax purposes, not indicative of a change in management's confidence or a strategic shift.

Key Dates

Keywords

Dyne Therapeutics, DYN, Form 4, Insider Transaction, John Cox, CEO, Restricted Stock Units, RSU Vesting, Tax Withholding, 10b5-1 Plan, Stock Sale