Boundless Bio (BOLD)
Wind-down-stage ecDNA oncology developer pursuing a merger with Serapha Bio.
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Wind-down-stage oncology developer whose legacy ecDNA platform and small-molecule programs generated no product revenue; pursuing a merger that would replace its operating business with Serapha Bio's investigational AATD base-editing program.
Operates as a clinical-stage oncology company in wind-down rather than a commercial drug seller: it has no approved products, no revenue and no remaining disclosed candidate in clinical development. Its legacy work combined the Spyglass discovery platform with ECHO, a diagnostic assay, to identify small-molecule ecDNA-directed therapies for oncogene-amplified cancers. BBI-355, BBI-825 and BBI-940 have all been discontinued following program reviews and human data.
Executes the wind-down from La Jolla while pursuing an all-stock merger with private Serapha Bio. If completed, the transaction would adopt the Serapha Bio name and AATD ticker and focus on SERP-01, an investigational in-vivo base editor for severe alpha-1 antitrypsin deficiency. Closing depends on stockholder approvals, Nasdaq approval, financing and other conditions.
Company facts
No analyst consensus on record.
EPSReportedEstimate
RevenueReportedEstimate
Balance sheet, Jun 30, 2026Cash & short-term investments $72.6M · Total debt $0 · Total assets $73.7M · Shareholders' equity $66.0M
- Revenue
- $0
- Operating income
- −$24.4M
- Net income
- −$23.7M
No dividends on record.
| Institutions36 holders · as of Mar 31, 2026 | 37.30% | 8.49M shares | |
| Insiders3 holders · as of Aug 28, 2026 | 23.16% | 5.27M shares | |
| Strategic holders2 holders · as of Aug 14, 2026 | 19.79% | 4.50M shares | |
| Otherremainder | 19.75% | 4.49M shares |
22.75M company shares as of Sep 3, 2026 · institutions as of Mar 31, 2026 · holders as of their latest filing
Top shareholders13F · 13D/G · Form 4
| Holder | Stake | Shares | Evidence |
|---|---|---|---|
Kevin TangInsider10 percent owner | 12.49% | 2.84M | Form 4filed Aug 28, 2026 ↗ |
FMR LLCInstitution | 11.85% | 2.70M | 13Fas of Mar 31, 2026 |
Tang Capital Management, LLCStrategic | 11.14% | 2.53M | 13Gfiled Jun 29, 2026 ↗ |
Zachary Hornby1Insiderdirector, officer: President & CEO | 10.67% | 2.43M | 13Gfiled Aug 27, 2026 ↗ |
ADAR1 Capital Management, LLCStrategic | 8.65% | 1.97M | 13Gfiled Aug 14, 2026 ↗ |
| See all 25 → | |||
- Zachary Hornby's transaction reports restate only vehicles that traded; the 2026 ownership statement (2.43M) is used instead.
13F — a manager's quarterly holdings · 13D/13G — an ownership statement filed at 5% or more · Form 4 — an insider's transaction report
Insider tradesForm 4
| Date | Insider | Role | Shares | Avg price |
|---|---|---|---|---|
| Aug 26, 2026 | Kevin Tang | 10 percent owner | −18,300 | $2.97 |
| Jul 17, 2026 | Kevin Tang | 10 percent owner | +265 | $2.44 |
| Jul 20, 2026 | Kevin Tang | 10 percent owner | +1,623 | $2.44 |
| Jul 21, 2026 | Kevin Tang | 10 percent owner | +2,975 | $2.44 |
| Jul 14, 2026 | Kevin Tang | 10 percent owner | +43,878 | $2.43 |
- Beam Therapeutics
Direct PiZ base-editing rival for severe AATD.
- Wave Life Sciences
RNA-editing challenger for AATD lung and liver disease.
- Takeda (ADR)
Late-stage liver RNAi and approved augmentation therapy in AATD.
- Grifols (ADR)
Established AAT augmentation therapy and a new subcutaneous option.
Compare
| Company | Price | Change | |||||
|---|---|---|---|---|---|---|---|
| Boundless Bio | $2.90 | +0.17% | $65.0M | — | — | — | — |
| Beam Therapeutics | $29.00 | −1.06% | $3.01B | — | — | 19.3 | −94.2% |
| Wave Life Sciences | $4.83 | −0.82% | $961.6M | — | — | 14.7 | −73.9% |
| Takeda (ADR) | $18.73 | +1.55% | $58.65B | 51.2 | 56.8 | 2.0 | +5.8% |
| Grifols (ADR) | $7.89 | +0.66% | $6.62B | 10.1 | — | 0.9 | −4.2% |
| Median | 30.6 | 56.8 | 8.4 | −39.0% |