Form4insider filings, from the source

Insider holders · CIK 0001782303

Boundless Bio, Inc. · BOLD

Every insider with a reported Table I holding at this company, ranked by their last-reported share count. A balance is only as fresh as its filing — the report date sits next to every row on purpose. ← Back to activity

InsiderDirect sharesIndirect sharesTotal reportedLast report (ET)From
TANG CAPITAL MANAGEMENT LLC10% Owner—2,840,6352,840,635Aug 28, 2026 · 4:16 pm EDTForm 4
Kevin Tang10% Owner—2,840,6352,840,635Aug 28, 2026 · 4:16 pm EDTForm 4
ARCH Venture Partners X, LLC10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Partners X Overage, L.P.10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Fund X Overage, L.P.10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Partners IX, LLC10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Partners IX, L.P.10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Partners IX Overage, L.P.10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Fund IX Overage, L.P.10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
ARCH Venture Fund IX, L.P.10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:43 pm EDTForm 4
Kristina Burow10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:44 pm EDTForm 4
Steven Gillis10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:44 pm EDTForm 4
Clinton Bybee10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:44 pm EDTForm 4
Robert Nelsen10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:44 pm EDTForm 4
Keith Crandell10% Owner—1,181,7661,181,766Jul 6, 2026 · 5:44 pm EDTForm 4

Balances come from each insider’s most recent filing that reports a Table I holding; an insider who left the company years ago still appears with their last-known figure and its date. Indirect totals collapse multiple vehicles (trusts, LLCs) into one number — open the filing for the breakdown. Shares as filed, not split-adjusted.