Third Rock Ventures, a major investor in Rapport Therapeutics, Inc. (NASDAQ: RAPP), reported the sale of common stock totaling approximately $17.1 million. The transactions took place on April 17, 2026 and were executed under an established Rule 10b5-1 trading plan adopted by the reporting person on November 21, 2025.
According to the Form 4 filing, a combined 426,005 shares were sold at prices ranging from $40.00 to $40.79 per share. The weighted average price for the block was $40.317. At the time of reporting in the filing, Rapport Therapeutics’ shares traded at $36.95, a level below the prices at which the insider sales occurred. InvestingPro data cited in the filing shows the stock has returned 256% over the past year, while InvestingPro analysis noted the company appears overvalued at current levels.
Holding structure and ownership details
The Form 4 was submitted by multiple Third Rock Ventures-related entities, including Third Rock Ventures V, L.P., and Third Rock Ventures VI, L.P., each identified as ten percent owners of Rapport Therapeutics. Post-transaction, Third Rock Ventures V, L.P. directly holds 6,709,228 shares of Rapport Therapeutics common stock.
Related entities Third Rock Ventures GP V, L.P. and TRV GP V, LLC disclaim beneficial ownership of those shares except to the extent of their pecuniary interest. Similarly, Third Rock Ventures VI, L.P. indirectly holds 969,218 shares, and its general partner entities, Third Rock Ventures GP VI, L.P. and TRV GP VI, LLC, disclaim beneficial ownership beyond any pecuniary interest. The reporting persons additionally stated that no Section 13(d) "group" exists between any TRV V related parties and any TRV VI related parties.
Clinical progress and corporate timeline
Separately from the insider sales, Rapport Therapeutics disclosed encouraging clinical data for RAP-219, its experimental epilepsy treatment. In the company’s Phase 2a study, patients experienced a 90% median reduction in clinical seizures during weeks 9-12 of the follow-up period and a 59% median reduction during weeks 13-16. Following a successful end-of-phase-2 meeting with the U.S. Food and Drug Administration, Rapport announced plans to accelerate its Phase 3 program, moving the planned start date to the second quarter of 2026.
Analyst response
Market analysts have responded to Rapport’s clinical and timeline updates with reiterated Buy ratings. Truist Securities maintained a Buy rating and set a $44.00 price target, citing the accelerated Phase 3 plans. Stifel also kept a Buy rating and a $56.00 price target, noting alignment with the company’s revised timeline. Jones Trading reiterated a Buy rating with a $50.00 price target following the company’s fiscal 2025 earnings announcement. These analyst actions are presented in the filing and related company disclosures.
What the filing shows
The Form 4 provides a contemporaneous record of the sales by entities under the Third Rock Ventures umbrella and clarifies ownership and disclaimer positions among affiliated entities. The use of a Rule 10b5-1 plan explains the structure under which shares were sold and the prior adoption date of November 21, 2025 provides the compliance context noted in the filing.
Taken together, the filing and the company’s clinical progress supply a compact snapshot of investor activity and corporate developments: an institutional shareholder executed planned sales while the company advances RAP-219 into a Phase 3 timeline supported by recent Phase 2a results and multiple analyst Buy reiterations.