Form 4: Third Rock Ventures Sells 133,618 Rapport Therapeutics Shares

Third Rock Ventures V, L.P. sold 133,618 shares of Rapport Therapeutics, Inc. (RAPP) at a weighted average price of $40.24 per share.

Summary

• Third Rock Ventures V, L.P. executed the sale of 133,618 shares of Rapport Therapeutics common stock.
• The transaction occurred on May 11, 2026, at a weighted average price of $40.244 per share.
• The sale was conducted pursuant to a pre-established Rule 10b5-1 trading plan adopted on November 21, 2025.
• Following the transaction, Third Rock Ventures V, L.P. retains direct ownership of 6,299,097 shares.
• Third Rock Ventures VI, L.P. continues to hold 969,218 shares of the issuer.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral event; while institutional selling can be perceived negatively, the use of a pre-planned 10b5-1 program suggests routine portfolio management rather than a reaction to negative company developments.

Positives

• The sale was executed under a pre-planned Rule 10b5-1 program, indicating the transaction was not based on sudden material non-public information.

Negatives

• Significant divestment by a major 10% institutional shareholder may signal a reduction in long-term conviction or portfolio rebalancing.

Risks

• Continued selling pressure from major institutional holders could negatively impact the stock price in the short term.

Future Outlook

No specific forward-looking guidance regarding the company's operations was provided; the filing relates strictly to the divestment activity of a major shareholder.

Industry Context

StockSavvy.ai notes that institutional divestment in the biotech sector is common as venture capital firms reach the end of their fund lifecycles or seek to rebalance portfolios following successful IPOs or clinical milestones.

Comparison to Industry Standards

• The use of Rule 10b5-1 plans is the industry standard for institutional investors to conduct orderly exits while avoiding insider trading concerns.
• Divestment by venture capital firms like Third Rock Ventures is typical for late-stage biotech holdings as they transition from early-stage incubation to public market maturity.

Stakeholder Impact

• Shareholders may experience minor price volatility due to the increased supply of shares in the market.
• The reduction in stake by a major venture capital firm may be interpreted as a signal of the company's transition toward a more mature, public-market-focused ownership structure.

Next Steps

• Continued monitoring of Form 4 filings to track further potential divestment by Third Rock Ventures or other major shareholders.

Key Dates

Keywords

Rapport Therapeutics, RAPP, Third Rock Ventures, Insider Trading, Form 4, Biotech, Equity Sale