Boundless Bio, Inc.: 10% owner Kevin Tang bought 21,640 shares

What happened

• Kevin Tang, listed as a 10% owner, reported open-market purchases of common stock. He acquired 5,800 shares at a weighted-average price of $2.40 on Oct 22, 2026 ($13,920); 6,234 shares at $2.38 on Oct 23, 2026 ($14,837); and 9,606 shares at $2.38 on Oct 26, 2026 ($22,862). Total purchased: 21,640 shares for $51,619.

Key details

• Transaction dates and prices: Oct 22, 2026 — 5,800 shares @ $2.40 ($13,920); Oct 23, 2026 — 6,234 shares @ $2.38 ($14,837); Oct 26, 2026 — 9,606 shares @ $2.38 ($22,862).
• Footnotes on pricing: the filing says reported prices are weighted-average prices and that the shares were purchased in multiple transactions at prices ranging from $2.36 to $2.40 (see footnotes). One footnote states a range of $2.39 to $2.40 for portions of the purchases.
• Beneficial holdings noted in the filing: Tang Capital Partners, LP beneficially owns 691,177 shares; Tang Capital Partners International, LP beneficially owns 950,804 shares; Tang Capital Partners III, Inc. beneficially owns 691,170 shares; Tang Capital Partners IV, Inc. beneficially owns 678,598 shares. The filing says Kevin Tang has a pecuniary interest in the shares held by those entities.
• Filing date: Oct 26, 2026 (reports transactions on Oct 22, Oct 23 and Oct 26, 2026).

Why it may matter

• The filing shows purchases, not option exercises, grants, or gifts.
• Kevin Tang is identified as a 10% owner, which the filing distinguishes from an executive role (a large holder, not an executive).
• A filing does not show why the insider traded or why the company acted.