Who owns BOLD?
Institutional ownership of Boundless Bio Inc. from Form 13F, Q2 2026
40 institutional managers reported holding Boundless Bio Inc. (BOLD) in Form 13F filings for Q2 2026, with 15,301,033 shares worth $38.3M. The largest reported holder was ARCH Venture Management, LLC. Managers that filed both quarters added a net 6,815,218 shares (+80.3%). 13 opened new positions and 8 sold out.
- Funds holding
- 40
- Value held
- $38.3M
- New / sold out
- 13 / 8
- Net shares, same filers
- +80.3%
Holdings as of June 30, 2026, the end of Q2 2026. Managers have 45 days after a quarter ends to file Form 13F (by August 14, 2026 for Q2 2026), so positions may have changed since.
Largest holders of BOLD
Share of 13F holdings is each fund's shares as a share of the 15,301,033 BOLD shares all 13F filers reported, not of shares outstanding.
Biggest buyers in Q2 2026
- ARCH Venture Management, LLC New+$6.7M
- Tang Capital Management LLC New+$6.4M
- ADAR1 Capital Management, LLC New+$4.9M
- Cormorant Asset Management, LP New+$2.5M
- Millennium Management LLC Added+$947K
- Affinity Asset Advisors, LLC New+$625K
- Acadian Asset Management LLC Added+$334K
- HRT Financial LP New+$290K
- Prelude Capital Management, LLC New+$210K
- Bridgeway Capital Management, LLC Added+$194K
Biggest sellers in Q2 2026
- Citadel Advisors LLC Trimmed-$3.0M
- Stonepine Capital Management, LLC Trimmed-$1.1M
- Sectoral Asset Management Inc Sold out-$746K
- FMR LLC Trimmed-$286K
- Sio Capital Management, LLC Sold out-$180K
- Landscape Capital Management, L.l.c. Sold out-$94K
- Ensign Peak Advisors, Inc Trimmed-$69K
- Gsa Capital Partners LLP Trimmed-$61K
- Walleye Capital LLC Sold out-$44K
- Geode Capital Management, LLC Trimmed-$27K
The change in shares since the quarter before, adjusted for stock splits and priced at the Q2 2026 value per share. Funds bought $24.1M and sold $5.6M; 10 added and 9 trimmed.
Schedule 13D and 13G filings on BOLD
Owners of more than 5% must file within days, so these can be newer than the 13F data.
- 2026-08-28Hornby Zachary SCHEDULE 13G filed by Boundless Bio Inc.Schedule 13G
- 2026-06-29TANG CAPITAL MANAGEMENT LLC SCHEDULE 13G filed by Boundless Bio Inc.Schedule 13G
- 2025-12-04CITADEL ADVISORS LLC SCHEDULE 13G filed by Boundless Bio Inc.Schedule 13G
Questions about BOLD ownership
- Who owns BOLD stock?
- 40 institutional investment managers reported BOLD positions in their Form 13F filings for Q2 2026, holding 15,301,033 shares worth $38.3M in total. ARCH Venture Management, LLC reported the largest position.
- Are funds buying or selling BOLD?
- In Q2 2026, 13 managers opened new BOLD positions, 10 added, 9 trimmed and 8 sold out. Managers that filed in both quarters added a net 6,815,218 shares.
- How current is this BOLD institutional ownership data?
- It covers holdings as of the end of Q2 2026. Managers have 45 days after the quarter ends to file Form 13F (by August 14, 2026 for Q2 2026), so positions may have changed since.
From the SEC's Form 13F data sets for Q2 2026: every 13F holdings report, matched to BOLD by CUSIP. Options are left out. BOLD news and filings · BOLD insider trades · Top funds