Third Rock Ventures IV, L.P.

Third Rock Ventures IV sells 477.4K TNGX shares at $10.15; stock now $7.77 (-23.5% below sale price).

Third Rock Ventures IV, a 10% owner, sold 477,401 shares at $10.15 on 2025-10-23, reducing holdings from 13.86M to 13.39M shares. At the current price of $7.77, the sale has already outperformed the subsequent market decline—a positive outcome for the seller. This is the sixth sale by this investor at TNGX within approximately two months; the prior five trades occurred between 2025-08-22 and 2025-09-25. Across all same-ticker sales, three showed 30-day gains (the most recent on 2025-09-16 up +30.3%) while two showed declines. The company remains unprofitable with quarterly revenue of $3.2M and a $-38.9M net loss, though revenue is growing at +15.2% annually. The rapid cadence of share reduction by a major holder warrants tracking for signals of shifting confidence in the company's near-term trajectory.

Third Rock Ventures IV sold 500,000 shares (500.0K shares) of TNGX at $8.02, reducing stake to 13.86M shares; stock up +25.8% in 30d.

Third Rock Ventures IV, a 10% owner, executed a partial reduction of its TNGX position, selling 500,000 shares at $8.02 while retaining 13.86M shares. The sale occurred during a period of strong momentum—the stock has appreciated +25.8% over the past 30 days and +55.2% over 90 days, now trading near its 52-week high of $8.53. Across the insider's cross-ticker track record, prior sells have demonstrated a 100.00% well-timed rate at the 90-day mark, suggesting a pattern of selling before declines. However, at this specific ticker TNGX, the 5 prior trades by this insider have not yet produced measurable 90-day outcomes except for two sales in August (showing positive 30-day returns of +8.6% and +12.2%), making it difficult to assess whether this latest sale follows the insider's proven cross-ticker timing discipline. The company remains unprofitable with net income of $-38.9M despite revenue growth of +15.2% year-over-year, a backdrop that frames the sale in the context of a small-cap biotech still far from sustained profitability.

Third Rock Ventures IV sells 363.5K TNGX shares at $7.04; rapid succession of 5 trades in 28 days signals reduced conviction in unprofitable biotech.

Third Rock Ventures IV, a 10% owner, executed its fourth sale of TNGX in 28 days (September 5–16, 2025), offloading 363,541 shares for $2.6M at $7.04. This follows three prior sales on August 19, 22, and September 5 and 8, establishing a clear pattern of repeated liquidation. The company remains unprofitable with net income of $-38.9M against quarterly revenue of $3.2M, providing material context for accelerated share reductions. At TNGX specifically, the insider's sole measurable prior sell (August 30, 2024) posted a 90-day return of -64.8%, indicating a well-timed prior exit before a sharp decline. The current stock price of $7.62 sits 27.4% below its 52-week high and only marginally above the transaction price, leaving minimal upside capture since the sale. The concentration of five sales within four weeks, each removing incrementally smaller holdings from a position that remains substantial at 14.36M shares, suggests methodical de-risking rather than a single discrete event.

Third Rock Ventures IV (10% owner) sells 729,365 shares across 2 transactions for $5.1M; stock down 41.6% from 52-week high

Third Rock Ventures IV, a 10% shareholder, executed 2 separate sales totaling 729,365 shares for $5,108,970.13, reducing holdings by 4.7% from 15.46M to 14.73M shares. The blended average sale price of $7.00 is modestly above the current price of $6.82, though the stock has declined 41.6% from its 52-week high of $11.68. Notably, across this insider's cross-ticker trade history, 3 of 3 prior sales at TNGX showed negative 90-day returns (ranging from -60.0% to -64.8%), with a 100% well-timed rate at the 90-day mark, suggesting a pattern of selling ahead of downward price movement. The company remains unprofitable with a net loss of $38,853,000 in the latest period against only $3,181,000 in quarterly revenue, creating material fundamental risk that may be influencing the selling activity.

Third Rock Ventures IV (10% owner) sold 302,194 shares of TNGX at $7.00; current price $6.68, down 44.0% from 52-week high

Third Rock Ventures IV, a 10% stakeholder, sold 302,194 shares at $7.00 on 2025-08-22, reducing its position by 1.9% while retaining 15,456,881 shares. The sale occurred near the stock's 52-week high of $11.93, with shares now trading at $6.68 (−44.0% from peak), suggesting the insider executed above current valuation. At this specific ticker, Third Rock's prior four measurable sells were all well-timed at the 90-day mark (−35.6%, −64.8%, −61.8%, −60.0%, and −41.7% respective 90-day returns), establishing a pattern of selling before material declines. The company's fundamental backdrop—negative net income of $-38,853,000.00 in the latest quarter against revenue of $3,181,000.00—underscores that this is a pre-revenue or near-pre-revenue biotech with substantial cash burn, making insider signal-watching particularly relevant. The timing and scale of this sale, viewed against the insider's same-ticker track record, merit close investor attention.

Third Rock Ventures IV sells 1,100,000 shares of TNGX at $7.01; prior 5 same-ticker sales all well-timed with -41.7% to -64.8% 90d returns.

Third Rock Ventures IV, holding 10% ownership, executed a sale of 1,100,000 shares (1.10M shares) at $7.01 for total value of $7,712,760.00 ($7.7M), reducing holdings by -6.5% to 15,759,075 shares (15.76M shares). The sale price of $7.01 lies -41.2% below the 52-week high of $11.93, suggesting the insider sold into a significantly depressed valuation. More striking is the insider's timing pattern at this ticker: all 5 prior sales at TNGX were well-timed at the 90-day mark, with post-sale 90-day returns ranging from -39.6% to -64.8%, indicating the insider consistently sold before material declines. The company remains unprofitable (net income of $-38,853,000.00 ($-38.9M) over the latest full fiscal year) despite showing annual revenue growth of +15.2%, leaving fundamental recovery uncertain. This sale aligns with the insider's demonstrated pattern of profitable exit timing at this specific ticker rather than a one-time liquidity event.

Third Rock Ventures IV sold 175,000 shares of TNGX at $11.60 on 2024-08-30, reducing stake from 17.18M to 17.00M shares.

Third Rock Ventures IV, a major 10% shareholder, sold 175,000 shares at $11.60, representing a 1.0% reduction in its substantial holding of 17.00M shares post-transaction. The sale occurred near the 52-week high of $12.88, only 15.8% below the peak, at a point when the stock was up 22.8% over 30 days and 50.6% over 90 days—a period of strong momentum. Across the insider's prior five trades at TNGX (all sells), the earliest measurable 30-day outcomes showed gains of 13.5% to 20.7%, meaning stocks rose after those sales rather than falling. The company remains unprofitable with a net loss of $25,551,000.00 on quarterly revenue of $19,875,000.00, and the current market price of $10.84 sits 6.5% below the transaction price, suggesting the sale has not yet proven well-timed on a near-term basis. This modest share reduction by a principal investor during a period of elevated valuation and positive price momentum, combined with the company's ongoing losses despite revenue growth of 46.9%, warrants observation as investors assess whether the shareholder rotation reflects internal signals about the company's growth trajectory.

10% Owner Third Rock Ventures IV sells 285,000 shares (285.0K) across two trades for $2.8M at $9.95 avg; stock up 19.8% in 30d, +50.3% in 90d

Third Rock Ventures IV, a 10% owner, executed 2 separate sales totaling 285,000 shares for $2,835,367.50 at a blended average price of $9.95 on 2024-08-16 and 2024-08-19, reducing its stake by 1.6%. The timing is noteworthy: the sales occurred while TNGX was trading 13.7% below its 52-week high of $12.88, yet the stock has since rallied 19.8% in the 30 days following the transactions and +50.3% over 90 days, suggesting the insider sold into weakness before a substantial recovery. At the same ticker (TNGX), Third Rock executed five consecutive sales in late July and early August 2024, indicating a deliberate multi-week liquidation pattern. The company's fundamentals show $19.9M in quarterly revenue with annual growth of 46.9%, but it remains unprofitable with $-25.6M net income in the most recent full fiscal year, typical of an early-stage development-stage biotech. The insider's cross-ticker track record shows a 100.00% well-timed 90-day sell rate, though this particular filing's outcomes cannot yet be measured at the 90-day horizon given the recent August dates.

Third Rock Ventures IV sells 235,000 TNGX shares (235.0K shares) for $2,316,494.00 in 3 transactions; 10% holder still retains 17,486,475 shares.

Third Rock Ventures IV, a 10% owner, executed 3 separate sales totaling 235,000 shares over three consecutive trading days (July 30–August 1, 2024) at a blended average price of $9.86, raising $2,316,494.00. The sale represents only a 1.3% reduction in the firm's holdings, leaving 17,486,475 shares post-transaction. Notably, this emerges within a broader pattern: the filer completed 5 additional sells at TANGO in the preceding week (July 18–25), suggesting a sustained portfolio reduction at this ticker during a period when the stock gained 16.6% over 30 days and 24.2% over 90 days, currently trading 26.6% below its 52-week high. The company is unprofitable (net income $-37,914,000.00 in its latest full fiscal year) despite strong revenue growth of 46.9%, and the latest quarterly revenue stands at only $6,471,000.00.

Third Rock Ventures IV sells 300,599 shares over 2 days at $9.83 avg; 5 rapid sales at TNGX within 7-day window; 90d track record 100% well-timed

Third Rock Ventures IV, a 10% owner, executed 2 separate sales totaling 300,599 shares for $2,955,931.29 at an average of $9.83 on 2024-07-24 and 2024-07-25. This filing is notable because it is the third transaction by this insider in three days; the SAME-TICKER HISTORY section reveals 5 sales at TNGX within a 7-day window (2024-07-17 through 2024-07-25), with only the earliest sale on 2024-02-20 showing measurable outcomes: a 90-day return of -36.1%, which constitutes a well-timed exit. The insider's cross-ticker track record across 5 prior open-market sales shows a 90-day well-timed rate of 100.00% and an average 90-day return of -36.1%, indicating historical success at exiting before declines. The company posted $6,471,000.00 in quarterly revenue but is unprofitable with a net loss of $-37,914,000.00, though annual revenue growth is +46.9%. Current stock price of $9.75 sits -24.3% below the 52-week high of $12.88. The rapid, sequential selling pattern combined with this insider's historical timing accuracy warrants monitoring of whether this constitutes an early directional signal, though outcomes of the recent four sales remain unmeasured.