Form 4: Third Rock Ventures Sells Tango Therapeutics Shares

Third Rock Ventures IV, L.P., a 10% owner and director, sold 363,541 shares of Tango Therapeutics common stock for a weighted average price of $7.04 per share.

Summary

• Third Rock Ventures IV, L.P., a 10% owner and director of Tango Therapeutics, Inc. (TNGX), reported a sale of common stock.
• The transaction involved the disposition of 363,541 shares of common stock.
• The shares were sold at a weighted average price of $7.04 per share, with prices ranging from $7.00 to $7.19.
• The sale was executed on September 16, 2025.
• Following this transaction, Third Rock Ventures IV, L.P. beneficially owns 14,363,975 shares of Tango Therapeutics common stock.
• The transaction was made pursuant to a contract, instruction, or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Sentiment

Score: 5

Explanation: The sentiment is neutral. While an insider sale by a 10% owner could be viewed negatively, the explicit mention of a Rule 10b5-1 plan indicates a pre-scheduled transaction, which typically carries less negative signaling than an unscheduled, discretionary sale.

Negatives

• A significant insider sale by a 10% owner and director, even if pre-planned, could be interpreted by some investors as a signal of reduced conviction in the company's near-term prospects.

Future Outlook

The filing does not contain any forward-looking statements or guidance regarding the company's future performance or strategic direction. It solely reports an insider transaction.

Management Comments

• Kevin Gillis, Chief Operating Officer of TRV GP IV, LLC, general partner of Third Rock Ventures GP IV, L.P., general partner of Third Rock Ventures IV, L.P., signed the filing.

Industry Context

Insider transactions, particularly by significant shareholders and directors, are closely watched by the market as they can sometimes signal management's or major investors' confidence (or lack thereof) in a company's future. However, sales executed under a Rule 10b5-1 plan are pre-scheduled and often for liquidity management, making them less indicative of immediate sentiment compared to unscheduled sales.

Related Party Transactions

• The sale of common stock by Third Rock Ventures IV, L.P., a 10% owner and director of Tango Therapeutics, Inc., constitutes a related party transaction.

Stakeholder Impact

• Shareholders may interpret the sale by a significant investor and director as a signal, though the 10b5-1 plan mitigates immediate concerns about insider sentiment.
• The transaction provides liquidity for Third Rock Ventures IV, L.P.

Key Dates

Keywords

Tango Therapeutics, TNGX, Third Rock Ventures, Insider Sale, Form 4, SEC Filing, Equity Transaction, 10b5-1 Plan