Boundless Bio, Inc. insider trading

Every open-market purchase and sale by Boundless Bio, Inc.'s officers, directors and largest shareholders since November 4, 2021, and what the share price did next.

Insider purchases, 5 years $1.9M 25 trades by 1 insider 3 months later: median +2.8% (−1.2% vs S&P 500) Insider sales, 5 years $134,031 3 trades by 3 insiders 3 months later: median +1.2% (−1.3% vs S&P 500)

Insider purchase Insider sale Marker size reflects trade value. Weekly closes adjusted for splits; may be delayed.

Boundless Bio, Inc. insider open-market trades
Date	Insider	Trade	Shares	Price	Value	1M after	3M after	6M after

From insiders' Form 4 filings with the SEC: open-market purchases and sales only (awards, option exercises and shares withheld for tax are excluded), combined to one line per insider per day. "Plan" marks trades the filing says were made under a pre-set Rule 10b5-1 trading plan, which are scheduled in advance. Price changes run from the close on the trade date; hover a figure for the change relative to the S&P 500. Past moves don't predict future ones.

Does following Boundless Bio, Inc.’s insiders pay?

From June 29, 2026 to October 29, 2026, 3 insiders reported 9 open-market purchases and 2 sales not made under a pre-set plan in Boundless Bio, Inc.

Boundless Bio, Inc.: each insider's record
Insider	Role	Purchases	12 months after their purchases	Beat the S&P 500	Sales	12 months after their sales	Latest report
Tang Kevin	10% owner	9	—	—	0	—	October 29, 2026
Gillis Steven and related entities	10% owner	0	—	—	1	—	July 6, 2026
Tang Capital Management LLC	10% owner	0	—	—	1	—	August 28, 2026

Moves are the shares’ return including dividends minus the S&P 500’s, from the close on the first trading day after each report; the number of trades with a finished 12-month window is in brackets. Green means the trade went the insider’s way (a purchase ahead of the index, a sale followed by the shares trailing it). A trade reported both by a director or officer and by a fund or company they are linked to counts once here, under the person. Purchases count only where the share price actually traded was at least $5. These figures describe what the shares did, not why anyone traded. Insiders across all companies.

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