Who owns Boundless Bio (BOLD)
Which tracked institutional funds hold BOLD, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See BOLD company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
The tracked-fund tape on BOLD is one-sided between 2026-Q1 and 2026-Q2: 13 added or opened and 3 trimmed or exited — on balance accumulating.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
BOLD’s largest tracked holder by dollar value, ARCH Venture Management, LLC, sizes it at 0.6% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.6pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in BOLD divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2026-Q1 and 2026-Q2, across 37 tracked filers holding BOLD, 21 increased or opened the position and 19 reduced or closed it; over the same quarter, open-market insider Form 4s were net purchases.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in BOLD between the 2026-Q1 and 2026-Q2 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 5
- ARCH Venture Management, LLC$7M
- TANG CAPITAL MANAGEMENT LLC$6M
- ADAR1 Capital Management, LLC$5M
- Cormorant Asset Management, LP$2M
- Affinity Asset Advisors, LLC$625K
Full exits 1
- SECTORAL ASSET MANAGEMENT INC$746K
Largest adds
- FMR LLC$3M
- MILLENNIUM MANAGEMENT LLC$1M
- VANGUARD CAPITAL MANAGEMENT LLC$880K
- WELLINGTON MANAGEMENT GROUP LLP$779K
- RENAISSANCE TECHNOLOGIES LLC$740K
- Alyeska Investment Group, L.P.$420K
Largest trims
- CITADEL ADVISORS LLC$1M
- Stonepine Capital Management, LLC$271K
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| ARCH Venture Management, LLC new | 2,694,095 | $7M | 16.0% | 2026-Q2 |
| FMR LLC trimmed | 2,581,055 | $6M | 15.3% | 2026-Q2 |
| TANG CAPITAL MANAGEMENT LLC new | 2,559,875 | $6M | 15.2% | 2026-Q2 |
| ADAR1 Capital Management, LLC new | 1,968,216 | $5M | 11.7% | 2026-Q2 |
| Cormorant Asset Management, LP new | 1,000,000 | $2M | 5.9% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 614,923 | $2M | 3.7% | 2026-Q2 |
| WELLINGTON MANAGEMENT GROUP LLP | 556,233 | $1M | 3.3% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC added | 478,639 | $1M | 2.8% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC added | 471,570 | $1M | 2.8% | 2026-Q2 |
| Alyeska Investment Group, L.P. | 300,000 | $750K | 1.8% | 2026-Q2 |
| Affinity Asset Advisors, LLC new | 250,000 | $625K | 1.5% | 2026-Q2 |
| RBF Capital, LLC | 200,000 | $500K | 1.2% | 2026-Q2 |
| Ensign Peak Advisors, Inc trimmed | 159,835 | $400K | 1.0% | 2026-Q2 |
| Stonepine Capital Management, LLC trimmed | 154,595 | $386K | 0.9% | 2026-Q2 |
| CITADEL ADVISORS LLC trimmed | 145,049 | $363K | 0.9% | 2026-Q2 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC added | 128,000 | $320K | 0.8% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC trimmed | 116,736 | $292K | 0.7% | 2026-Q2 |
| BlackRock, Inc. added | 88,495 | $221K | 0.5% | 2026-Q2 |
| PRELUDE CAPITAL MANAGEMENT, LLC added | 83,998 | $210K | 0.5% | 2026-Q2 |
| Rangeley Capital, LLC new | 74,000 | $185K | 0.4% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO | 65,136 | $163K | 0.4% | 2026-Q2 |
| JANE STREET GROUP, LLC added | 64,323 | $161K | 0.4% | 2026-Q2 |
| SUPERSTRING CAPITAL MANAGEMENT LP new | 55,356 | $138K | 0.3% | 2026-Q2 |
| NORTHERN TRUST CORP trimmed | 34,824 | $87K | 0.2% | 2026-Q2 |
| XTX Topco Ltd trimmed | 33,361 | $83K | 0.2% | 2026-Q2 |
| Qube Research & Technologies Ltd added | 20,207 | $51K | 0.1% | 2026-Q2 |
| China Universal Asset Management Co., Ltd. new | 16,900 | $42K | 0.1% | 2026-Q2 |
| STATE STREET CORP | 15,962 | $40K | 0.1% | 2026-Q2 |
| MORGAN STANLEY | 13,000 | $32K | 0.1% | 2026-Q2 |
| Caitong International Asset Management Co., Ltd added | 10,443 | $26K | 0.1% | 2026-Q2 |
| Pure Financial Advisors, LLC | 10,100 | $25K | 0.1% | 2026-Q2 |
| Tower Research Capital LLC (TRC) trimmed | 348 | $870 | 0.0% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 176 | $440 | 0.0% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 179 | $439 | 0.0% | 2026-Q2 |
| Financial Management Professionals, Inc. new | 2 | $5 | 0.0% | 2026-Q2 |
| UBS Group AG | 2 | $5 | 0.0% | 2026-Q2 |
| SBI Securities Co., Ltd. added | 2 | $5 | 0.0% | 2026-Q2 |
| SECTORAL ASSET MANAGEMENT INC | 678,574 | $746K | 1.8% | 2026-Q1 stale (1 quarter behind) |
| Sio Capital Management, LLC | 163,679 | $180K | 0.4% | 2026-Q1 stale (1 quarter behind) |
| GSA CAPITAL PARTNERS LLP added | 96,824 | $107K | 0.3% | 2026-Q1 stale (1 quarter behind) |
| LANDSCAPE CAPITAL MANAGEMENT, L.L.C. trimmed | 85,792 | $94K | 0.2% | 2026-Q1 stale (1 quarter behind) |
| Walleye Capital LLC | 39,624 | $44K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| Squarepoint Ops LLC trimmed | 16,374 | $18K | 0.0% | 2026-Q1 stale (1 quarter behind) |
| ACADIAN ASSET MANAGEMENT LLC | 12,610 | $12K | 0.0% | 2026-Q1 stale (1 quarter behind) |
| CITIGROUP INC trimmed | 8,837 | $10K | 0.0% | 2026-Q1 stale (1 quarter behind) |
| Vanguard Global Advisers, LLC new | 429 | $472 | 0.0% | 2026-Q1 stale (1 quarter behind) |
| Optiver Holding B.V. | 168 | $185 | 0.0% | 2026-Q1 stale (1 quarter behind) |
| CWM, LLC trimmed | 8 | $9 | 0.0% | 2026-Q1 stale (1 quarter behind) |
| VANGUARD GROUP INC added | 662,757 | $795K | 1.9% | 2025-Q4 stale (2 quarters behind) |
| Abel Hall, LLC trimmed | 12,865 | $15K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| Nolet Wealth Management, LLC new | 11,323 | $14K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| BANK OF AMERICA CORP /DE/ added | 7,758 | $9K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| BARCLAYS PLC trimmed | 2 | $2 | 0.0% | 2025-Q4 stale (2 quarters behind) |
| Nextech Invest, Ltd. | 1,228,069 | $2M | 3.6% | 2025-Q3 stale (3 quarters behind) |
| NORGES BANK added | 157,211 | $546K | 1.3% | 2025-Q3 stale (3 quarters behind) |
| Redmile Group, LLC trimmed | 245,458 | $302K | 0.7% | 2025-Q3 stale (3 quarters behind) |
| Almitas Capital LLC trimmed | 86,808 | $107K | 0.3% | 2025-Q3 stale (3 quarters behind) |
| GOLDMAN SACHS GROUP INC trimmed | 14,299 | $18K | 0.0% | 2025-Q3 stale (3 quarters behind) |
| Y-Intercept (Hong Kong) Ltd new | 55,242 | $56K | 0.1% | 2025-Q2 stale (4 quarters behind) |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 32,211 | $33K | 0.1% | 2025-Q2 stale (4 quarters behind) |
| HRT FINANCIAL LP new | 27,509 | $27K | 0.1% | 2025-Q2 stale (4 quarters behind) |
| WELLS FARGO & COMPANY/MN trimmed | 2,582 | $3K | 0.0% | 2025-Q2 stale (4 quarters behind) |
| RAYMOND JAMES FINANCIAL INC new | 1,000 | $1K | 0.0% | 2025-Q2 stale (4 quarters behind) |
| Clearstead Advisors, LLC new | 24 | $25 | 0.0% | 2025-Q2 stale (4 quarters behind) |
| EverSource Wealth Advisors, LLC trimmed | 2 | $2 | 0.0% | 2025-Q2 stale (4 quarters behind) |
| Royal Bank of Canada trimmed | 97 | — | 0.0% | 2025-Q2 stale (4 quarters behind) |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | 0 | — | 0.0% | 2025-Q2 stale (4 quarters behind) |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.