Third Rock Ventures V, L.P. 4

What Happened
Third Rock Ventures V, L.P. (a reported 10% owner) sold a total of 276,513 shares of Rapport Therapeutics (RAPP) in two dispositions. On 2026-05-07 it sold 271,495 shares at a weighted average price of $40.12 for proceeds of $10,892,651 (prices in that batch ranged $40.00–$40.60). On 2026-05-08 it sold 5,018 shares at a weighted average price of $40.31 for proceeds of $202,256 (prices in that batch ranged $40.10–$40.80). Total proceeds were about $11.095 million. These were sales (code S) — typically routine liquidity by an institutional holder rather than a corporate insider purchase.

Key Details

• Transaction dates: 2026-05-07 (271,495 shares) and 2026-05-08 (5,018 shares).
• Prices: weighted averages reported ($40.12 and $40.31); underlying per-share ranges given in footnotes.
• Total shares sold: 276,513; total proceeds: $11,094,907 ($11.095M).
• Plan/authorization: Transactions executed pursuant to a Rule 10b5-1 plan dated November 21, 2025 (Footnote F1).
• Ownership structure: Shares held directly by Third Rock Ventures V, L.P.; related GP entities disclaim beneficial ownership except to their pecuniary interest (Footnotes F3, F5). Reporting person disclaims existence of a Section 13(d) group between certain related funds.
• Filing timeliness: Form 4 filed 2026-05-11 for transactions on 2026-05-07 and 05-08 — appears timely (filed within required business-day window).
• Shares owned after transaction: Not specified in the provided filing excerpt.

Context
This is institutional selling by a major investor operating under a pre-arranged 10b5-1 plan, which is designed to permit scheduled trades regardless of later company developments. Such sales are generally treated as liquidity actions by the holder and are not, by themselves, a direct signal about management’s view of the company.