Cox John 4

What Happened

• John Cox, CEO and President (and a director) of Dyne Therapeutics (DYN), sold 3,311 shares in an open-market/automatic sale on May 13, 2026. The weighted average sale price was $18.36 per share, resulting in proceeds of roughly $60,790. The sale was to satisfy tax withholding obligations tied to the vesting of restricted stock units (RSUs).

Key Details

• Transaction date: 2026-05-13; weighted average price reported $18.36 (sales executed in the $18.20–$18.41 range).
• Total shares sold: 3,311; total proceeds ≈ $60,790. Reporting person can provide breakdown of shares sold at each price upon request.
• Purpose: Automatic sale to cover tax withholding on RSUs vested Feb 12, 2026 (per RSU agreement); described as a non-discretionary sale consistent with the affirmative defense under Rule 10b5-1.
• Holdings note: Filing references 268,645 unvested RSUs included in the reporting person's holdings; some shares are held in a trust for a child. The filing does not state a full post-transaction total share count in the provided excerpt.
• Filing timing: Report filed May 14, 2026 for the May 13 transaction (appears timely).

Context

• This was an automatic, tax-withholding sale tied to RSU vesting rather than an independent sale decision by the insider; such transactions are common and not necessarily a signal of sentiment. The amounts involved are modest relative to large insider buys/sells.