Boundless Bio, Inc.
BOLD- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001782303
In the last 90 days, Boundless Bio, Inc. insiders filed 5 open-market purchases and 2 sales; 40 institutions reported holding it in 13F filings for Q2 2026, worth $38.3M in total; no superinvestor holds it.
Holders of 5% or more of BOLD
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Boundless Bio, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Citadel Advisors LLC | 13G | 6.40%1.43M shares | New | Dec 4, 20251 filing | Dec 4, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
2 Schedule 13D and 13G filings on Boundless Bio, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Dec 4, 20256:35 PM ET | Citadel Advisors LLCand 6 others | 13G | 6.40%1.43M shares | New | Nov 26, 2025 | SEC |
| Aug 14, 20255:57 PM ET | Ra Capital Management, L.P.and 3 others | 13G/A | 0.00%0 shares | –Below 5% | Jun 30, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Boundless Bio, Inc. shares.
No Form 144 notices for Boundless Bio, Inc. are on file.