Third Rock Ventures V, L.P. and affiliated entities filed a Form 4 with the SEC on November 3, 2026, disclosing the acquisition of common stock in Rapport Therapeutics, Inc. (NASDAQ:RAPP) through a private placement transacted on October 30, 2026.

Key Highlights

  • Transaction date: October 30, 2026, pursuant to a Securities Purchase Agreement dated October 28, 2026.
  • Shares acquired by Third Rock Ventures V, L.P.: 238,095 shares of common stock at $21 per share, acquired directly.
  • Shares acquired by Third Rock Ventures VI, L.P.: 1,190,476 shares of common stock at $21 per share, acquired indirectly.
  • Beneficial ownership following transactions: TRV V directly holds 6,518,620 shares; TRV VI directly holds 2,159,694 shares.
  • Transaction type: Code "A" (acquisition) in a private placement; no derivative securities were involved.
  • Board representation: Reid Huber, a partner at Third Rock Ventures, serves on the board of directors of Rapport Therapeutics, Inc. and has been deputized to represent the reporting persons.

Third Rock Ventures Private Placement in Rapport Therapeutics at $21 Per Share

According to the filing, the acquisitions were made pursuant to a Securities Purchase Agreement dated October 28, 2026, between Rapport Therapeutics, Inc. and both Third Rock Ventures V, L.P. ("TRV V") and Third Rock Ventures VI, L.P. ("TRV VI"). Both transactions occurred on October 30, 2026, with each share acquired at a price of $21. TRV V acquired 238,095 shares directly, bringing its direct beneficial ownership to 6,518,620 shares. TRV VI acquired 1,190,476 shares directly, bringing its indirect beneficial ownership reported by TRV V to 2,159,694 shares.

The filing identifies six reporting persons: Third Rock Ventures V, L.P.; Third Rock Ventures GP V, LP; TRV GP V, LLC; Third Rock Ventures VI, L.P.; Third Rock Ventures GP VI, L.P.; and TRV GP VI, LLC, all located at 201 Brookline Ave, Suite 1401, Boston, Massachusetts 02215. Each is identified as both a director (by deputization) and a 10% owner in relation to the issuer. The filing notes that each of TRV GP V, TRV GP V LLC, TRV GP VI, and TRV GP VI LLC disclaims beneficial ownership of the respective shares "except to the extent of its pecuniary interest therein, if any."

The filing further states that "each of Reporting Persons disclaims the existence of a Section 13(d) 'group' as between any TRV V related parties and any TRV VI related parties." Reid Huber, identified as a partner at Third Rock Ventures, serves on the board of directors of the issuer "by deputization," making each reporting person potentially deemed a director under Section 16 of the Securities Exchange Act of 1934, as amended, according to the filing's remarks section.

What Was Disclosed

Six affiliated Third Rock Ventures entities reported the acquisition of a combined 1,428,571 shares of Rapport Therapeutics common stock at $21 per share on October 30, 2026, through a private placement, with resulting direct and indirect beneficial ownership positions also disclosed.