Boundless Bio, Inc.
BOLD- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001782303
In the last 90 days, Boundless Bio, Inc. insiders filed 6 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.
Open-market trades, last 90 days
Open-market purchases (P) and sales (S) by Boundless Bio, Inc. insiders, counted by Form 4 filing. Trades with a flagged price and duplicate filings are left out.
- Open-market buys
- 6 filings
- 1 insider, $1.52M in total
- Open-market sells
- 2 filings
- 2 insiders, $94.2K in total
- Insiders trading
- 2
- Net value
- +$1.42M
- Purchases minus sales
Insider roster
Directors, officers and 10% owners who have filed a Form 4 for Boundless Bio, Inc., current and former, most recent filer first. Last reported holding is the position after the last non-derivative trade in their latest filing.
| Name | Title | Last reported holding | Last filing | Filings, past year |
|---|---|---|---|---|
| Tang Kevin C | 10% Owner | 2,840,635Indirect | Aug 28, 2026 | 7 |
| Tang Capital Management LLC | 10% Owner | 2,840,635Indirect | Aug 28, 2026 | 7 |
| Crandell Keith | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| Nelsen Robert | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| Bybee Clinton | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| Gillis Steven | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| Burow Kristina | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Fund IX, L.P. | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Fund IX Overage, L.P. | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Partners IX Overage, L.P. | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Partners IX, L.P. | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Partners IX, LLC | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Fund X Overage, L.P. | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Partners X Overage, L.P. | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| ARCH Venture Partners X, LLC | 10% Owner | 0Indirect | Jul 6, 2026 | 1 |
| Lim Jonathan E | Director | 550,915Indirect | Jun 15, 2026 | 1 |
| Lew Jennifer | Director | – | Jun 15, 2026 | 1 |
| Whiting Nancy | Director | – | Jun 15, 2026 | 1 |
| Christensen James | Director | – | Jun 15, 2026 | 1 |
| Hinkle David A | See Remarks | – | Jan 26, 2026 | 1 |
| Hornby Zachary | President & CEO | – | Jan 26, 2026 | 1 |
| Hassig Christian | Chief Scientific Officer | – | Jan 26, 2026 | 1 |
| Oien Jessica | See Remarks | – | Jan 26, 2026 | 1 |
| Doebele Robert | Chief Medical Officer | – | Jan 26, 2026 | 1 |
| Brennan Christine | Director | – | Jun 23, 2025 | 0 |
| Abdollahian Neil | Chief Business Officer | – | Aug 20, 2024 | 0 |
| Wagner Klaus W. | Chief Medical Officer | – | Aug 20, 2024 | 0 |
| Rubin Jami | Chief Financial Officer | – | Aug 20, 2024 | 0 |
| RA Capital Healthcare Fund LP | 10% Owner | 295,844Indirect | Apr 4, 2024 | 0 |
| Ra Capital Management, L.P. | 10% Owner | 295,844Indirect | Apr 4, 2024 | 0 |
| Kolchinsky Peter | 10% Owner | 295,844Indirect | Apr 4, 2024 | 0 |
| Shah Rajeev M. | 10% Owner | 295,844Indirect | Apr 4, 2024 | 0 |
| RA Capital Nexus Fund II, L.P. | 10% Owner | 295,844Indirect | Apr 4, 2024 | 0 |
| Wellington Biomedical Innovation Master Investors (Cayman) I L.P. | 10% Owner | 556,233 | Apr 2, 2024 | 0 |
Insider trades
Each row adds up one type of transaction in one Form 4 filing. Only open-market purchases (P) and sales (S) are shown by default; use the filters to see grants, option exercises and other codes.
| Filed (ET) | Trade date | Filing delay | Insider | Transaction | Shares | Avg price | Value | Holding change | Flags |
|---|---|---|---|---|---|---|---|---|---|
| Aug 28, 2026 (view filing)4:16 PM ET | Aug 26 | 2 days | Tang Kevin C and 1 other10% Owner | SSale | −18.3K | $2.97 | −$54.4K | −0.6%2.84M after | |
| Jul 21, 2026 (view filing)7:38 PM ET | Jul 17-21 | 4 days | Tang Kevin C and 1 other10% Owner | PPurchase | +4.86K | $2.44 | +$11.9K | +0.2%2.86M after | 3 lots |
| Jul 16, 2026 (view filing)8:10 PM ET | Jul 14-16 | 2 days | Tang Kevin C and 1 other10% Owner | PPurchase | +64.0K | $2.43 | +$155.6K | +2.3%2.85M after | 3 lots |
| Jul 13, 2026 (view filing)7:06 PM ET | Jul 9-13 | 4 days | Tang Kevin C and 1 other10% Owner | PPurchase | +91.6K | $2.42 | +$222.1K | +3.4%2.79M after | 3 lots |
| Jul 8, 2026 (view filing)8:06 PM ET | Jul 6-8 | 2 days | Tang Kevin C and 1 other10% Owner | PPurchase | +57.2K | $2.48 | +$141.9K | +2.2%2.70M after | 3 lots |
| Jul 6, 2026 (view filing)5:44 PM ET | Jul 1 | 5 days | Crandell Keith and 4 others10% Owner | SSale | −16.0K | $2.49 | −$39.8K | −100.0%0 after | Duplicate filing |
| Jul 6, 2026 (view filing)5:43 PM ET | Jul 1 | 5 days | ARCH Venture Fund IX, L.P. and 7 others10% Owner | SSale | −16.0K | $2.49 | −$39.8K | −100.0%0 after | |
| Jul 2, 2026 (view filing)7:45 PM ET | Jun 30-Jul 2 | 2 days | Tang Kevin C and 1 other10% Owner | PPurchase | +107.5K | $2.50 | +$268.9K | +4.2%2.64M after | 4 lots |
| Jun 29, 2026 (view filing)7:56 PM ET | Jun 25-29 | 4 days | Tang Kevin C and 1 other10% Owner | PPurchase | +286.3K | $2.50 | +$714.8K | +12.7%2.53M after | 6 lots |
| Apr 4, 2024 (view filing)4:30 PM ET | Apr 2 | 2 days | Crandell Keith and 3 others10% Owner | PPurchase | +200.0K | $16.00 | +$3.20M | +20.4%1.18M after | 2 lotsDuplicate filing |
| Apr 4, 2024 (view filing)4:30 PM ET | Apr 2 | 2 days | ARCH Venture Fund IX, L.P. and 7 others10% Owner | PPurchase | +200.0K | $16.00 | +$3.20M | +20.4%1.18M after | 2 lotsDuplicate filing |
| Apr 4, 2024 (view filing)4:15 PM ET | Apr 2 | 2 days | RA Capital Healthcare Fund LP and 4 others10% Owner | PPurchase | +312.5K | $16.00 | +$5.00M | New position295.8K after | 2 lots |
| Apr 4, 2024 (view filing) | Apr 2 | 2 days | Burow KristinaDirector, 10% Owner | PPurchase | +200.0K | $16.00 | +$3.20M | +20.4%1.18M after | 2 lots |