BOLDNasdaqPharmaceutical PreparationsFiscal year ends December 31
Boundless Bio, Inc.
Financials through Q2 FY2026, quarter ended Jun 30, 2026Last filing: 10-Q on Aug 7, 2026
$2.31−0.03 (-1.28%)
Close on Oct 19, 2026
- Market cap
- $51.86M
- P/E (TTM)
- –
- Dividend yield
- –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
67.3%
15M of 23M shares
Institutional holders
40
13 new, 8 sold out
Net institutional buying
7M
In Q2 2026
Insider trades, 12 months
22 buys · 3 sales
Net bought $1.38M
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Kristina Burow | 2,699,970 | – | 13D (active) | Apr 2, 2024 |
| FMR LLC | 2,684,022 | 12.00% | 13G (passive) amendment | Dec 31, 2025 |
| Kevin Tang | 2,533,845 | 11.30% | 13G (passive) | Jun 23, 2026 |
| Zachary Hornby | 2,426,857 | 9.80% | 13G (passive) | Oct 14, 2025 |
| ADAR1 Capital Management, LLC | 1,968,216 | 8.80% | 13G (passive) | Jun 30, 2026 |
| Bayer US Holding LP | 1,615,201 | 7.30% | 13G (passive) | Apr 2, 2024 |
| Kenneth Griffin | 1,433,388 | 6.40% | 13G (passive) | Nov 26, 2025 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of BOLD | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| ARCH Venture Management, LLC | 2,694,095 | 11.84% | $6.74M | New | 0.61% |
| FMR LLC | 2,581,055 | 11.35% | $6.45M | −114,400 | 0.00% |
| Tang Capital Management LLC | 2,559,875 | 11.25% | $6.40M | New | 0.29% |
| ADAR1 Capital Management, LLC | 1,968,216 | 8.65% | $4.92M | New | 0.23% |
| Cormorant Asset Management, LP | 1,000,000 | 4.40% | $2.50M | New | 0.13% |
| Vanguard Capital Management LLC | 614,923 | 2.70% | $1.54M | +17,731 | 0.00% |
| Wellington Management Group Llp | 556,233 | 2.45% | $1.39M | – | 0.00% |
| Millennium Management LLC | 478,639 | 2.10% | $1.20M | +378,764 | 0.00% |
| Renaissance Technologies LLC | 471,570 | 2.07% | $1.18M | +72,570 | 0.00% |
| Alyeska Investment Group, L.P. | 300,000 | 1.32% | $750.00K | – | 0.00% |
| Affinity Asset Advisors, LLC | 250,000 | 1.10% | $625.00K | New | 0.03% |
| RBF Capital, LLC | 200,000 | 0.88% | $500.00K | – | 0.02% |
| Ensign Peak Advisors, Inc | 159,835 | 0.70% | $399.59K | −27,665 | 0.00% |
| Stonepine Capital Management, LLC | 154,595 | 0.68% | $386.49K | −443,087 | 0.22% |
| Acadian Asset Management LLC | 146,757 | 0.65% | $365 | +134,147 | 0.00% |
| Citadel Advisors LLC | 145,049 | 0.64% | $362.62K | −1,197,082 | 0.00% |
| Bridgeway Capital Management, LLC | 128,000 | 0.56% | $320.00K | +77,500 | 0.01% |
| Geode Capital Management, LLC | 116,736 | 0.51% | $291.84K | −10,840 | 0.00% |
| Hrt Financial LP | 116,288 | 0.51% | $290 | New | 0.00% |
| BlackRock, Inc. | 88,495 | 0.39% | $221.24K | +17,820 | 0.00% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 40 | 15M | 67.3% | 13 / 10 | 9 / 8 | 10M | 3M |
| Q1 2026 | 36 | 8M | 37.3% | 7 / 6 | 11 / 6 | 1M | 1M |
| Q4 2025 | 36 | 9M | 39.5% | 6 / 11 | 9 / 5 | 1M | 2M |
| Q3 2025 | 35 | 10M | 42.7% | 1 / 7 | 15 / 10 | 1M | 1M |
| Q2 2025 | 44 | 10M | 43.0% | 11 / 7 | 19 / 21 | 1M | 8M |
| Q1 2025 | 54 | 17M | 74.6% | 9 / 12 | 15 / 8 | 6M | 1M |
| Q4 2024 | 55 | 13M | 57.0% | 9 / 28 | 4 / 9 | 1M | 2M |
| Q3 2024 | 55 | 13M | 58.4% | 13 / 11 | 16 / 4 | 1M | 1M |
| Q2 2024 | 47 | 14M | 60.9% | 21 / 12 | 8 / 17 | 1M | 2M |
| Q1 2024 | 43 | 15M | 64.1% | 43 / 0 | 0 / 0 | 15M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
| Fund | Shares | % of BOLD | Value | % of fund | As of |
|---|---|---|---|---|---|
| Fidelity Growth Company Fund | 900,270 | 3.96% | $1.31M | 0.00% | May 31, 2026 |
| Vanguard Total Stock Market Index Fund | 445,181 | 1.96% | $1.11M | 0.00% | Jun 30, 2026 |
| Fidelity Growth Company K6 Fund | 226,498 | 1.00% | $328.42K | 0.00% | May 31, 2026 |
| Fidelity Series Growth Company Fund | 202,816 | 0.89% | $294.08K | 0.00% | May 31, 2026 |
| Vanguard Extended Market Index Fund | 152,011 | 0.67% | $380.03K | 0.00% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 82,655 | 0.36% | $119.85K | 0.00% | May 31, 2026 |
| Ultra-Small Company Fund | 77,500 | 0.34% | $193.75K | 0.20% | Jun 30, 2026 |
| iShares Micro-Cap ETF | 58,851 | 0.26% | $147.13K | 0.01% | Jun 30, 2026 |
| Ultra-Small Company Market Fund | 50,500 | 0.22% | $126.25K | 0.09% | Jun 30, 2026 |
| Vanguard Balanced Index Fund | 17,731 | 0.08% | $44.33K | 0.00% | Jun 30, 2026 |
| Fidelity Series Total Market Index Fund | 15,411 | 0.07% | $22.35K | 0.00% | May 31, 2026 |
| Fidelity Total Market Index Fund | 8,946 | 0.04% | $12.97K | 0.00% | May 31, 2026 |
| 1290 VT Micro Cap Portfolio | 4,089 | 0.02% | $10.22K | 0.00% | Jun 30, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Zachary Hornby | President & CEO, Director | 256,410 | 1.13% | Jan 26, 2026 |
| Jessica Oien | See Remarks | – | – | Jan 26, 2026 |
| Robert Doebele | Chief Medical Officer | – | – | Jan 26, 2026 |
| David A. Hinkle | See Remarks | 100 | 0.00% | Jan 26, 2026 |
| Christian Hassig | Chief Scientific Officer | 25,641 | 0.11% | Jan 26, 2026 |
| Jennifer Lew | Director | – | – | Jun 15, 2026 |
| Jonathan E. Lim | Director | 653,479 | 2.87% | Jun 15, 2026 |
| James Christensen | Director | – | – | Jun 15, 2026 |
| Nancy Whiting | Director | – | – | Jun 15, 2026 |
| Christine Brennan | Director | – | – | Jun 23, 2025 |
| Capital Management Llc Tang | 10% owner | 2,840,635 | 12.49% | Aug 28, 2026 |
| Kevin Tang | 10% owner | 2,858,935 | 12.57% | Aug 28, 2026 |
| Robert Nelsen | 10% owner | – | – | Jul 6, 2026 |
| Kristina Burow | 10% owner | 1,181,766 | 5.20% | Jul 6, 2026 |
| Clinton Bybee | 10% owner | – | – | Jul 6, 2026 |
| Keith Crandell | 10% owner | 27,349 | 0.12% | Jul 6, 2026 |
| Steven Gillis | 10% owner | 828,570 | 3.64% | Jul 6, 2026 |
| ARCH Venture Partners X, LLC | 10% owner | – | – | Jul 6, 2026 |
| ARCH Venture Partners X Overage, L.P. | 10% owner | – | – | Jul 6, 2026 |
| ARCH Venture Fund IX Overage, L.P. | 10% owner | – | – | Jul 6, 2026 |
| ARCH Venture Fund X Overage, L.P. | 10% owner | – | – | Jul 6, 2026 |
| ARCH Venture Partners IX Overage, L.P. | 10% owner | – | – | Jul 6, 2026 |
| ARCH Venture Partners IX, LLC | 10% owner | 617,092 | 2.71% | Jul 6, 2026 |
| ARCH Venture Fund IX, L.P. | 10% owner | – | – | Jul 6, 2026 |
| ARCH Venture Partners IX, L.P. | 10% owner | 683,759 | 3.01% | Jul 6, 2026 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Capital Management Llc Tang 10% owner | Aug 26, 2026 | Sale | −18,300 | $2.97 | $54.35K | 2,840,635 |
| Kevin Tang 10% owner | Jul 21, 2026 | Buy | +2,975 | $2.44 | $7.26K | 2,858,935 |
| Kevin Tang 10% owner | Jul 20, 2026 | Buy | +1,623 | $2.44 | $3.96K | 2,855,960 |
| Kevin Tang 10% owner | Jul 17, 2026 | Buy | +265 | $2.44 | $647 | 2,854,337 |
| Kevin Tang 10% owner | Jul 16, 2026 | Buy | +18,491 | $2.44 | $45.12K | 2,854,072 |
| Kevin Tang 10% owner | Jul 15, 2026 | Buy | +1,600 | $2.44 | $3.90K | 2,835,581 |
| Kevin Tang 10% owner | Jul 14, 2026 | Buy | +43,878 | $2.43 | $106.62K | 2,833,981 |
| Kevin Tang 10% owner | Jul 13, 2026 | Buy | +48,211 | $2.42 | $116.67K | 2,790,103 |
| Kevin Tang 10% owner | Jul 10, 2026 | Buy | +43,367 | $2.43 | $105.38K | 2,741,892 |
| Kevin Tang 10% owner | Jul 9, 2026 | Buy | +7 | $2.48 | $17 | 2,698,525 |
| Kevin Tang 10% owner | Jul 8, 2026 | Buy | +14,338 | $2.46 | $35.27K | 2,698,518 |
| Kevin Tang 10% owner | Jul 7, 2026 | Buy | +15,810 | $2.48 | $39.21K | 2,684,180 |
| Kevin Tang 10% owner | Jul 6, 2026 | Buy | +27,062 | $2.49 | $67.38K | 2,668,370 |
| Kevin Tang 10% owner | Jul 2, 2026 | Buy | +9,821 | $2.49 | $24.45K | 2,641,308 |
| Steven Gillis 10% owner | Jul 1, 2026 | Sale | −16,000 | $2.49 | $39.84K | 0 |
| Steven Gillis 10% owner | Jul 1, 2026 | Option exercise | +16,000 | $1.03 | $16.48K | 16,000 |
| ARCH Venture Partners IX, L.P. 10% owner | Jul 1, 2026 | Sale | −16,000 | $2.49 | $39.84K | 0 |
| ARCH Venture Partners IX, L.P. 10% owner | Jul 1, 2026 | Option exercise | +16,000 | $1.03 | $16.48K | 16,000 |
| Kevin Tang 10% owner | Jul 1, 2026 | Buy | +71,612 | $2.49 | $178.31K | 2,631,487 |
| Kevin Tang 10% owner | Jun 30, 2026 | Buy | +100 | $2.50 | $250 | 2,559,875 |
| Kevin Tang 10% owner | Jun 30, 2026 | Buy | +25,930 | $2.54 | $65.86K | 2,559,775 |
| Kevin Tang 10% owner | Jun 29, 2026 | Buy | +63,985 | $2.47 | $158.04K | 2,533,068 |
| Kevin Tang 10% owner | Jun 29, 2026 | Buy | +777 | $2.48 | $1.93K | 2,533,845 |
| Kevin Tang 10% owner | Jun 26, 2026 | Buy | +134 | $2.54 | $340 | 2,469,083 |
| Kevin Tang 10% owner | Jun 26, 2026 | Buy | +75,047 | $2.55 | $191.37K | 2,468,949 |
| Kevin Tang 10% owner | Jun 25, 2026 | Buy | +145,880 | $2.48 | $361.78K | 2,393,392 |
| Kevin Tang 10% owner | Jun 25, 2026 | Buy | +510 | $2.56 | $1.31K | 2,393,902 |
| Jonathan E. Lim Director | Apr 2, 2024 | Conversion | +525,274 | – | – | 550,915 |
| ARCH Venture Partners IX, LLC 10% owner | Apr 2, 2024 | Conversion | +589,743 | – | – | 617,092 |
| ARCH Venture Partners IX, LLC 10% owner | Apr 2, 2024 | Buy | +133,333 | $16.00 | $2.13M | 1,181,766 |
| ARCH Venture Partners IX, LLC 10% owner | Apr 2, 2024 | Conversion | +787,545 | – | – | 828,570 |
| ARCH Venture Partners IX, LLC 10% owner | Apr 2, 2024 | Conversion | +1,048,433 | – | – | 1,048,433 |
| ARCH Venture Partners IX, LLC 10% owner | Apr 2, 2024 | Buy | +66,667 | $16.00 | $1.07M | 683,759 |
| Steven Gillis 10% owner | Apr 2, 2024 | Buy | +66,667 | $16.00 | $1.07M | 683,759 |
| Steven Gillis 10% owner | Apr 2, 2024 | Conversion | +1,048,433 | – | – | 1,048,433 |
| Steven Gillis 10% owner | Apr 2, 2024 | Conversion | +787,545 | – | – | 828,570 |
| Steven Gillis 10% owner | Apr 2, 2024 | Conversion | +589,743 | – | – | 617,092 |
| Steven Gillis 10% owner | Apr 2, 2024 | Buy | +133,333 | $16.00 | $2.13M | 1,181,766 |
| Kristina Burow Director, 10% owner | Apr 2, 2024 | Buy | +133,333 | $16.00 | $2.13M | 1,181,766 |
| Kristina Burow Director, 10% owner | Apr 2, 2024 | Conversion | +589,743 | – | – | 617,092 |
| Kristina Burow Director, 10% owner | Apr 2, 2024 | Conversion | +787,545 | – | – | 828,570 |
| Kristina Burow Director, 10% owner | Apr 2, 2024 | Buy | +66,667 | $16.00 | $1.07M | 683,759 |
| Kristina Burow Director, 10% owner | Apr 2, 2024 | Conversion | +1,048,433 | – | – | 1,048,433 |
| Peter Kolchinsky 10% owner | Apr 2, 2024 | Buy | +296,875 | $16.00 | $4.75M | 1,884,787 |
| Peter Kolchinsky 10% owner | Apr 2, 2024 | Conversion | +280,219 | – | – | 280,219 |
| Peter Kolchinsky 10% owner | Apr 2, 2024 | Buy | +15,625 | $16.00 | $250.00K | 295,844 |
| Peter Kolchinsky 10% owner | Apr 2, 2024 | Conversion | +1,587,912 | – | – | 1,587,912 |
| Biomedical Innovation Master Investors (Cayman) I. L.P. Wellington 10% owner | Apr 2, 2024 | Conversion | +189,933 | – | – | 189,933 |
| Biomedical Innovation Master Investors (Cayman) I. L.P. Wellington 10% owner | Apr 2, 2024 | Conversion | +366,300 | – | – | 556,233 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.