Cox John 4

What Happened
John Cox, CEO & President and a director of Dyne Therapeutics (DYN), disposed of 2,683 shares on June 16, 2026. The filing reports a weighted-average price of $18.33 (sales executed in the $18.00–$18.70 range), for total gross proceeds of approximately $49,179. The sale was an automatic disposition to satisfy tax withholding obligations related to the vesting of restricted stock units (RSUs) granted on December 4, 2024, and was not a discretionary trade.

Key Details

• Transaction date: 2026-06-16; Form 4 filed 2026-06-17 (timely).
• Action: Sale (code S) of 2,683 shares; weighted-average price $18.33; price range $18.00–$18.70; proceeds ≈ $49,179. (Footnote F2: price is weighted average; breakdown available on request.)
• Reason: Automatic sale to satisfy tax withholding on vested RSUs (Footnote F1). The RSU agreement provides for automatic sale and is treated as a binding contract consistent with a Rule 10b5-1 affirmative defense.
• Ownership after transaction: filing notes 259,564 unvested RSUs (Footnote F3); total post-sale share count not specified in the provided excerpt.
• Additional note: Some shares are held in a trust for the benefit of a child of the reporting person (Footnote F4).

Context
This was a tax-withholding sale tied to RSU vesting—common and generally considered routine rather than a signal of negative sentiment. The filing emphasizes the sale was automatic under the RSU agreement and not a discretionary trade. Retail investors typically weigh purchases more heavily than routine withholding sales when interpreting insider activity.