Dyne Therapeutics Director Jason P. Rhodes Sells 247,760 Shares Under Rule 10b5-1 Plan

This Form 4 filing reports that Jason P. Rhodes, a director of Dyne Therapeutics, sold 247,760 shares of common stock across multiple transactions from June 23-25, 2026. The sales were executed pursuant to a Rule 10b5-1 trading plan adopted on March 19, 2026, with weighted average prices ranging from $21.02 to $21.13 per share. The shares were sold from three different Atlas Venture funds where Rhodes has indirect ownership interests. Following these transactions, Rhodes retains indirect ownership of 7,962 shares through Atlas Venture Associates XI, L.P. The sales represent significant divestment activity by a company director, though executed under a pre-established trading plan, which typically indicates planned rather than discretionary selling.