Kersten Dirk 4

What Happened Dirk Kersten, a director of Dyne Therapeutics (DYN), sold 129,672 shares of the company's common stock in open-market transactions on March 11, 2026. The shares were sold for a weighted average price of $19.52 per share, for total proceeds of approximately $2,530,562. The sales were made pursuant to a Rule 10b5-1 trading plan adopted by ForDyne B.V. on November 11, 2025; the reported price is a weighted average of multiple trades that occurred at prices between $18.88 and $19.87.

Key Details

• Transaction date: 2026-03-11; Form 4 filed: 2026-03-13 (filed within the typical 2‑business‑day window).
• Shares sold: 129,672; weighted average price: $19.52; total proceeds: ~$2,530,562.
• Price range across multiple trades: $18.88 to $19.87; the filer will provide per‑price quantities on request (per footnote).
• The shares were held directly by ForDyne B.V.; ForDyne is jointly owned by Forbion funds. Footnotes describe the complex ownership and that the reporting person is a partner in the management entities and disclaims beneficial ownership except for any pecuniary interest.
• Transaction code: S = Sale. This sale was executed under a pre-established 10b5-1 plan (footnote).

Context This was a sale (not a purchase or option exercise) carried out under a 10b5-1 plan, which typically allows scheduled trades by insiders and is often considered routine rather than a direct signal of the insider’s short‑term view. The shares were held and sold by an institutional vehicle (ForDyne B.V.) connected to Forbion-managed funds; the filing notes delegation of voting/dispositive authority among the related management entities.