Third Rock Ventures V, L.P. 4

What Happened
Third Rock Ventures V, L.P. (a greater-than-10% institutional owner of Rapport Therapeutics, ticker RAPP) sold 18,572 shares in a transaction on May 26, 2026. The shares were sold at a weighted-average price of $40.05 per share (prices ranged $40.00–$40.10), for aggregate proceeds of approximately $743,753. The sales were effected pursuant to a Rule 10b5-1 trading plan adopted November 21, 2025.

Key Details

• Transaction date: 2026-05-26; Form 4 filed: 2026-05-28 (filing appears timely).
• Transaction type/code: Sale (S); shares sold: 18,572; weighted-average price: $40.05; total proceeds ≈ $743,753.
• Price range: $40.00 to $40.10; the reporting person can provide a per-price breakdown on request (footnote).
• Ownership after transaction: Not specified in the provided excerpt of the filing.
• Footnotes: trades were under a 10b5-1 plan (F1); weighted-average/price range disclosure (F2); organizational/beneficial ownership disclaimers for Third Rock entities (F3, F4) — institutional structure noted and disclaimers that certain affiliated entities disclaim beneficial ownership except to extent of pecuniary interest.

Context

• This is institutional insider selling under a pre-set trading plan (10b5-1), which is typically routine and pre-planned rather than a real-time signal of sentiment.
• As a >10% owner, Third Rock is an institutional investor, not a company executive; such sales can reflect portfolio or fund-level management rather than management view on the company.