Comparable stake leader
FMR LLC
SEC ownership of Boundless Bio, Inc.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001782303.
Disclosed value leader
TANG CAPITAL MANAGEMENT LLC
Comparable rows
38/50
Latest evidence
30 Jun 2026
- Public ticker
- BOLD on Nasdaq
- Parsed ownership sources
-
13D/G, 13F, and 3/4/5
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
FMR LLC
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
38 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
FMR LLC
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
30 Jun 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001782303
- Issuer location
- La Jolla, CA
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of Boundless Bio, Inc. (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
FMR LLC
Disclosed value leader
TANG CAPITAL MANAGEMENT LLC
Comparable rows
38/50
Latest evidence
30 Jun 2026
13D/G
13F
3/4/5
Lead comparable stake: 12%
12 rows are not safely comparable across share classes.
13D/G row: FMR LLC
Showing 1-8 of 50 holder rows.
Quick read
FMR LLC leads the comparable SEC ownership view at 12%.
38 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens FMR LLC's linked filing trail.
Comparable ownership
Top 5
FMR LLC
12%
TANG CAPITAL MANAGEMENT LLC
11%
CITADEL ADVISORS LLC
6.4%
Kevin Tang
12%
SECTORAL ASSET MANAGEMENT INC
3%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| FMR LLC |
13D/G
13F
Company
|
12%
|
$3,086,625
2,684,022 shares
|
$0 | 31 Dec 2025 |
| TANG CAPITAL MANAGEMENT LLC |
3/4/5
13D/G
10%+ Owner
|
11%
from 13D/G
|
$6,576,856
2,641,308 shares
|
+$983,648 | 30 Jun 2026 |
| CITADEL ADVISORS LLC |
13D/G
13F
Kenneth Griffin · Company
|
6.4%
|
$1,763,067
1,433,388 shares
|
$0 | 26 Nov 2025 |
| Kevin Tang |
3/4/5
10%+ Owner
|
12%
|
$6,576,856
2,641,308 shares
|
+$983,648 | 30 Jun 2026 |
| SECTORAL ASSET MANAGEMENT INC |
13F
Company
|
3%
|
$746,431
678,574 shares
|
— | 31 Mar 2026 |
| Stonepine Capital Management, LLC |
13F
Company
|
2.7%
|
$657,450
597,682 shares
|
— | 31 Mar 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13F
Company
|
2.7%
|
$656,911
597,192 shares
|
— | 31 Mar 2026 |
| WELLINGTON MANAGEMENT GROUP LLP |
13F
Company
|
2.5%
|
$611,856
556,233 shares
|
— | 31 Mar 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to buying over the last 12 months. Net value: +$1,967,297.
Buys
$1,967,297
Insiders: 2
Sells
$0
Insiders: 0
Net
+$1,967,297
Shares: +787,592
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 787,592
Shares: 0
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 787,592 | 0 | $1,967,297 | $0 | +$1,967,297 |
| 3-6 | 0 | 0 | $0 | $0 | $0 |
| 6-9 | 0 | 0 | $0 | $0 | $0 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-20 of 20 reporting-owner rows connected to Boundless Bio, Inc.. Open a relationship link for the CIK-to-CIK filing trail.
Rows
20
Largest Forms 3/4/5 holder
Kevin Tang
Net 12M change
+$1,967,296
Latest report
30 Jun 2026
Recent insider transactions for Boundless Bio, Inc.
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Tang Kevin | BOLD | Common Stock | Purchase | 0.37% | $24,454 | $2.49 | 9,821 | 2,641,308 | 02 Jul 2026 | By LP |
| Kevin Tang | BOLD | Common Stock | Purchase | 0.37% | $24,454 | $2.49 | 9,821 | 2,641,308 | 02 Jul 2026 | By LP |
| Tang Kevin | BOLD | Common Stock | Purchase | 2.8% | $178,314 | $2.49 | 71,612 | 2,631,487 | 01 Jul 2026 | By LP |
| Kevin Tang | BOLD | Common Stock | Purchase | 2.8% | $178,314 | $2.49 | 71,612 | 2,631,487 | 01 Jul 2026 | By LP |
| Tang Kevin | BOLD | Common Stock | Purchase | 1.03% | $66,112 | $2.54 | 26,030 | 2,559,875 | 30 Jun 2026 | By LP |
| Kevin Tang | BOLD | Common Stock | Purchase | 1.03% | $66,112 | $2.54 | 26,030 | 2,559,875 | 30 Jun 2026 | By LP |
| Tang Kevin | BOLD | Common Stock | Purchase | 2.62% | $159,970 | $2.47 | 64,762 | 2,533,845 | 29 Jun 2026 | By LP |
| Kevin Tang | BOLD | Common Stock | Purchase | 2.62% | $159,970 | $2.47 | 64,762 | 2,533,845 | 29 Jun 2026 | By LP |
| Tang Kevin | BOLD | Common Stock | Purchase | 3.14% | $191,710 | $2.55 | 75,181 | 2,469,083 | 26 Jun 2026 | By LP |
| Kevin Tang | BOLD | Common Stock | Purchase | 3.14% | $191,710 | $2.55 | 75,181 | 2,469,083 | 26 Jun 2026 | By LP |
| Tang Kevin | BOLD | Common Stock | Purchase | 6.51% | $363,088 | $2.48 | 146,390 | 2,393,902 | 25 Jun 2026 | By LP |
| Kevin Tang | BOLD | Common Stock | Purchase | 6.51% | $363,088 | $2.48 | 146,390 | 2,393,902 | 25 Jun 2026 | By LP |
| Nancy Whiting | BOLD | Stock Option (right to buy) | Award | 32,000 | 32,000 | 15 Jun 2026 | Direct | |||
| Jonathan E. Lim | BOLD | Stock Option (right to buy) | Award | 48,000 | 48,000 | 15 Jun 2026 | Direct | |||
| James Christensen | BOLD | Stock Option (right to buy) | Award | 32,000 | 32,000 | 15 Jun 2026 | Direct | |||
| Jennifer Lew | BOLD | Stock Option (right to buy) | Award | 32,000 | 32,000 | 15 Jun 2026 | Direct | |||
| Robert Doebele | BOLD | Stock Option (right to buy) | Award | 230,000 | 230,000 | 23 Jan 2026 | Direct | |||
| Jessica Oien | BOLD | Stock Option (right to buy) | Award | 220,000 | 220,000 | 23 Jan 2026 | Direct | |||
| Ph.D. Christian Hassig | BOLD | Stock Option (right to buy) | Award | 230,000 | 230,000 | 23 Jan 2026 | Direct | |||
| Zachary Hornby | BOLD | Stock Option (right to buy) | Award | 600,000 | 600,000 | 23 Jan 2026 | Direct | |||
| David A. Hinkle | BOLD | Stock Option (right to buy) | Award | 140,000 | 140,000 | 23 Jan 2026 | Direct |
* marks a reported price that did not pass the local price check.