BOLD · Boundless Bio, Inc. · Holdings

$2.83 -0.01 (-0.35%) At close · Sep 11

Market Cap

$64.38M

22.75M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Use institutional holdings through the 13F API or MCP →

Quarter:

Holders: 40

Total Value: $38,252,572

Total Shares: 15,301,033

Institutional Ownership Trend

10 quarters

Holder Concentration

Across 40 13F filers · Δ vs Mar 31, 2026

Top Holder

17.6%

−14.2 pts

Top 5

70.6%

+0.8 pts

Top 10

86.4%

−2.7 pts

HHI

1,147

Broadly held−380

Quarterly Activity

vs Mar 31, 2026

New

Increased

Decreased

Sold Out

Unchanged

Holder count: +4

Institutional value: +310.4%

Shares held: +80.3%

Top Buyers

vs Mar 31, 2026

Institution	Added	Now Holds
Mega MILLENNIUM MANAGEMENT LLC	+378,764	478,639
Large ACADIAN ASSET MANAGEMENT LLC	+134,147	146,757
Mid BRIDGEWAY CAPITAL MANAGEMENT, LLC	+77,500	128,000
Large RENAISSANCE TECHNOLOGIES LLC	+72,570	471,570
Mega BlackRock, Inc.	+17,820	88,495

Top Sellers

vs Mar 31, 2026

Institution	Sold	Now Holds
Mega CITADEL ADVISORS LLC	−1,197,082	145,049
Small Stonepine Capital Management, LLC	−443,087	154,595
Mega FMR LLC	−114,400	2,581,055
Large Ensign Peak Advisors, Inc	−27,665	159,835
Mid GSA CAPITAL PARTNERS LLP	−24,471	72,353

Top New Positions

vs Mar 31, 2026

Institution	Acquired	Value (USD)
Mid ARCH Venture Management, LLC	2,694,095	$6,735,237
Mid TANG CAPITAL MANAGEMENT LLC	2,559,875	$6,399,687
Mid ADAR1 Capital Management, LLC	1,968,216	$4,920,540
Mid Cormorant Asset Management, LP	1,000,000	$2,500,000
Mid Affinity Asset Advisors, LLC	250,000	$625,000

Top Sold-Out Positions

vs Mar 31, 2026

Institution	Previously Held	Last Value (USD)
Small SECTORAL ASSET MANAGEMENT INC	678,574	$746,431
Small Sio Capital Management, LLC	163,679	$180,046
Mid LANDSCAPE CAPITAL MANAGEMENT, L.L.C.	85,792	$94,370
Large Walleye Capital LLC	39,624	$43,586
Large Squarepoint Ops LLC	16,374	$18,011

Filter: New 13 Increased 10 Reduced 9 Sold out 9 Unchanged 8

Showing 40 of 40

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

ARCH Venture Management, LLC

$6,735,237

17.61%

2,694,095

FMR LLC

$6,452,637

16.87%

2,581,055

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Fidelity Management & Research Co LLC	1,332,980	$3,332,450	51.6%	Defined
FIDELITY MANAGEMENT TRUST CO	1,243,083	$3,107,707	48.2%	Defined
Fidelity Institutional Asset Management Trust Co	4,992	$12,480	0.2%	Defined

TANG CAPITAL MANAGEMENT LLC

$6,399,687

16.73%

2,559,875

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
TANG KEVIN	2,559,875	$6,399,687	100.0%	Other

ADAR1 Capital Management, LLC

$4,920,540

12.86%

1,968,216

Cormorant Asset Management, LP

$2,500,000

6.54%

1,000,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Chen Bihua	1,000,000	$2,500,000	100.0%	Defined

VANGUARD CAPITAL MANAGEMENT LLC

$1,537,307

4.02%

614,923

WELLINGTON MANAGEMENT GROUP LLP

$1,390,582

3.64%

556,233

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Wellington Management Company LLP	556,233	$1,390,582	100.0%	Defined

MILLENNIUM MANAGEMENT LLC

$1,196,597

3.13%

478,639

RENAISSANCE TECHNOLOGIES LLC

$1,178,925

3.08%

471,570

Alyeska Investment Group, L.P.

$750,000

1.96%

300,000

Affinity Asset Advisors, LLC

$625,000

1.63%

250,000

RBF Capital, LLC

$500,000

1.31%

200,000

Ensign Peak Advisors, Inc

$399,587

1.04%

159,835

Stonepine Capital Management, LLC

$386,487

1.01%

154,595

ACADIAN ASSET MANAGEMENT LLC

$366,892

0.96%

146,757

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Acadian Inc	146,757	$366,892	100.0%	Defined

CITADEL ADVISORS LLC

$362,622

0.95%

145,049

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	145,049	$362,622	100.0%	Defined

BRIDGEWAY CAPITAL MANAGEMENT, LLC

$320,000

0.84%

128,000

GEODE CAPITAL MANAGEMENT, LLC

$291,839

0.76%

116,736

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GEODE CAPITAL MANAGEMENT TRUST COMPANY, LLC	20,683	$51,707	17.7%	Defined
Held directly	96,053	$240,132	82.3%	Defined

HRT FINANCIAL LP

$290,720

0.76%

116,288

BlackRock, Inc.

$221,236

0.58%

88,495

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BlackRock Investment Management, LLC	4,089	$10,222	4.6%	Sole
BlackRock Fund Advisors	58,851	$147,127	66.5%	Sole
BlackRock Institutional Trust Company, N.A.	25,555	$63,887	28.9%	Sole

PRELUDE CAPITAL MANAGEMENT, LLC

$209,995

0.55%

83,998

Rangeley Capital, LLC

$185,000

0.48%

74,000

GSA CAPITAL PARTNERS LLP

$180,882

0.47%

72,353

VANGUARD FIDUCIARY TRUST CO

$162,840

0.43%

65,136

JANE STREET GROUP, LLC

$160,807

0.42%

64,323

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	45,870	$114,675	71.3%	Defined
Jane Street Global Trading, LLC	18,453	$46,132	28.7%	Defined

SUPERSTRING CAPITAL MANAGEMENT LP

$138,390

0.36%

55,356

NORTHERN TRUST CORP

$87,060

0.23%

34,824

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
NORTHERN TRUST CO joint	34,824	$87,060	100.0%	Defined

XTX Topco Ltd

$83,402

0.22%

33,361

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
XTX EXECUTION SERVICES LLC joint	33,361	$83,402	100.0%	Defined

Qube Research & Technologies Ltd

$50,517

0.13%

20,207

China Universal Asset Management Co., Ltd.

$42,250

0.11%

16,900

STATE STREET CORP

$39,905

0.10%

15,962

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
STATE STREET GLOBAL ADVISORS TRUST COMPANY	15,962	$39,905	100.0%	Defined

MORGAN STANLEY

$32,500

0.08%

13,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY SMITH BARNEY LLC	13,000	$32,500	100.0%	Defined

Caitong International Asset Management Co., Ltd

$26,107

0.07%

10,443

Pure Financial Advisors, LLC

$25,250

0.07%

10,100

Tower Research Capital LLC (TRC)

$870

0.00%

348

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Latour Trading LLC (Latour)	348	$870	100.0%	Defined

JPMORGAN CHASE & CO

$447

0.00%

179

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
J.P. Morgan Securities LLC	10	$25	5.6%	Defined
J.P. Morgan Securities plc	169	$422	94.4%	Defined

BNP PARIBAS ARBITRAGE, SA

$440

0.00%

176

Financial Management Professionals, Inc.

0.00%

UBS Group AG

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS AG	2	$5	100.0%	Defined

SBI Securities Co., Ltd.

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Landscape High Leverage Fund, LP	16,204	$17,824	18.9%	Defined
LANDSCAPE OFFSHORE HL FUND LTD.	44,584	$49,042	52.0%	Defined
Held directly	25,004	$27,504	29.1%	Sole

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Squarepoint Capital LLP	16,374	$18,011	100.0%	Defined

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citigroup Financial Products Inc. joint	8,837	$9,720	100.0%	Defined

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Optiver VOF	168	$184	100.0%	Defined

Key facts CIK 1782303 CUSIP 10170A100 13F (30d) 30 filings 30 filers Visit website Investor relations