Latest Period
Q1 2026
Security Snapshot
Boundless Bio, Inc. - Common Stock, par value $0.0001 per share (BOLD) Institutional Ownership
CUSIP: 10170A100
13F Institutional Holders and Ownership History from Q1 2024 to Q1 2026
Institutions Reporting
36
Shares (Excl. Options)
8,485,823
Price
$1.10
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- Security type / class
- Equity / Common Stock, par value $0.0001 per share
- Symbol
- BOLD on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 8,485,823
- Total 13F value
- $9,333,021
- Portfolio coverage rank
- 0%
- Share change
- -295,115
- Value change
- -$347,924
- Number of holders
- 36
- Shares outstanding
- 22,366,850
- SEC-reported price per share
- $1.63
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
2 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- BOLD - Boundless Bio, Inc. - Common Stock, par value $0.0001 per share is tracked under CUSIP 10170A100.
- 36 institutions reported positions in Q1 2026.
- 2 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 35 to 36 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $10,536,019 to $9,333,021.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 36 institutions filings for Q1 2026.
Security key
10170A100
Latest holder period
Q1 2026
13F holders
36
13D/G owners
2
CIK / CUSIP context first
Open Q1 2026 holders
BOLD full holder history
Boundless Bio, Inc. SEC filings
Boundless Bio, Inc. company facts
Boundless Bio, Inc. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 10170A100:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
2
Security
BOLD
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| FMR LLC | 12% | $3,086,625 | 2,684,022 | FMR LLC | 31 Dec 2025 | |||
| CITADEL ADVISORS LLC | 6.4% | $1,763,067 | 1,433,388 | Kenneth Griffin | 26 Nov 2025 |
As of 31 Mar 2026, 36 institutional investors reported holding 8,485,823 shares of Boundless Bio, Inc. - Common Stock, par value $0.0001 per share (BOLD). This represents 38% of the company’s total 22,366,850 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
38%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| FMR LLC | 12% | 2,695,455 | +0.43% | 0% | $2,965,000 |
| CITADEL ADVISORS LLC | 6% | 1,342,131 | -0.87% | 0% | $1,476,344 |
| SECTORAL ASSET MANAGEMENT INC | 3% | 678,574 | 0% | 0.62% | $746,431 |
| Stonepine Capital Management, LLC | 2.7% | 597,682 | -16% | 0.58% | $657,450 |
| VANGUARD CAPITAL MANAGEMENT LLC | 2.7% | 597,192 | 0% | 0% | $656,911 |
| WELLINGTON MANAGEMENT GROUP LLP | 2.5% | 556,233 | 0% | 0% | $611,856 |
| RENAISSANCE TECHNOLOGIES LLC | 1.8% | 399,000 | +17% | 0% | $438,900 |
| Alyeska Investment Group, L.P. | 1.3% | 300,000 | 0% | 0% | $330,000 |
| RBF Capital, LLC | 0.89% | 200,000 | 0% | 0.01% | $220,000 |
| Ensign Peak Advisors, Inc | 0.84% | 187,500 | 0% | 0% | $206,250 |
| Sio Capital Management, LLC | 0.73% | 163,679 | 0% | 0.03% | $180,047 |
| GEODE CAPITAL MANAGEMENT, LLC | 0.57% | 127,576 | +36% | 0% | $140,333 |
| MILLENNIUM MANAGEMENT LLC | 0.45% | 99,875 | -26% | 0% | $109,862 |
| GSA CAPITAL PARTNERS LLP | 0.43% | 96,824 | +55% | 0.01% | $107,000 |
| LANDSCAPE CAPITAL MANAGEMENT, L.L.C. | 0.38% | 85,792 | -33% | 0.01% | $94,370 |
| BlackRock, Inc. | 0.32% | 70,675 | +5.4% | 0% | $77,743 |
| VANGUARD FIDUCIARY TRUST CO | 0.29% | 65,136 | 0% | 0% | $71,650 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 0.23% | 50,500 | 0% | 0% | $55,550 |
| Walleye Capital LLC | 0.18% | 39,624 | 0% | 0% | $43,586 |
| XTX Topco Ltd | 0.16% | 34,671 | -12% | 0% | $38,138 |
| Qube Research & Technologies Ltd | 0.08% | 17,492 | -6.5% | 0% | $19,241 |
| Squarepoint Ops LLC | 0.07% | 16,374 | 0% | $18,011 | |
| STATE STREET CORP | 0.07% | 15,962 | 0% | 0% | $17,558 |
| MORGAN STANLEY | 0.06% | 13,000 | 0% | 0% | $14,300 |
| ACADIAN ASSET MANAGEMENT LLC | 0.06% | 12,610 | 0% | 0% | $12,000 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
9
Latest
Q1 2026
Rows shown
1-9 of 9
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 8,485,823 | $9,333,021 | -$347,924 | $1.10 | 36 |
| 2025 Q4 | 8,780,936 | $10,536,019 | -$1,070,476 | $1.20 | 35 |
| 2025 Q3 | 9,621,325 | $11,833,310 | -$174,692 | $1.23 | 34 |
| 2025 Q2 | 9,787,223 | $9,883,853 | -$4,661,743 | $1.01 | 42 |
| 2025 Q1 | 13,012,498 | $19,647,091 | -$249,812 | $1.51 | 52 |
| 2024 Q4 | 12,962,230 | $37,589,408 | -$2,220,511 | $2.90 | 53 |
| 2024 Q3 | 13,275,578 | $46,065,519 | -$1,783,862 | $3.47 | 54 |
| 2024 Q2 | 13,842,210 | $53,440,888 | -$15,936,188 | $3.87 | 47 |
| 2024 Q1 | 14,582,563 | $208,788,470 | +$208,607,723 | $14.25 | 43 |