John Cox sold $131K of DYN stock

John Cox, CEO & President of Dyne Therapeutics, Inc. (DYN), sold 4,986 shares of DYN stock worth $131K, per an SEC Form 4 filed Aug 17, 2026.

The sale was pre-arranged (a 10b5-1 plan or an option exercise), not a fresh decision.

The trade happened on Aug 13, 2026, 4 days before it was made public.

DYN has moved -30.4% since the trade date, from $25.96 to $18.07 (Nov 6, 2026 close).