$BOLD

$2.41 +$0.05 (2.12%) Close

$BOLD Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 22.7M shares outstanding

Who owns BOLD?

By type of holder

Institutions 67.3% Insiders 32.7% Everyone else 0.0%

Concentration Top 10 holders own 56.1%

FMR LLC 11.4% · ARCH Venture Management, LLC 11.8%

Institutional ownership

67.3%

+30.0 pts vs last qtr

Institutional holders

+4 vs last qtr

Net shares bought

+6.8M

by institutions in Q2 2026

New / sold out

13 / 9

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

ARCH Venture Management, LLC NEW +2.7M
Tang Capital Management LLC NEW +2.6M

Biggest sellers in Q2 2026

Citadel Advisors LLC −1.2M
Sectoral Asset Management Inc SOLD OUT −678.6K

Who is planning to sell?

No insider has filed a notice of proposed sale (Form 144) for Boundless Bio, Inc. in the last 12 months.

Is your stake being diluted?

Diluted share count, FY2023–FY2025

+1738.8%

+328.81% a year

Each share's claim on the business

−94.6%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

— vs $17M

over 3 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years0% 3–5 years0% 1–3 years41% Under 1 year59%

Quarterly turnover

73.3%

of institutional shares changed hands

Top 10 managers, median time held

1.3 years

Super Investors

Investment managers reporting BOLD on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
F FMR LLC	2.6M	11.35%	−114.4K (−4.2%)	2024	0.0%
Shares held by quarter Peak holding3.3M (Q4'24) Change over 8 quarters−757.0K Share of the company11.350% FMR LLC's full portfolio →
AV ARCH Venture Management, LLC	2.7M	11.84%	NEW	Q2 '26	0.6%
Shares held by quarter Peak holding2.7M (Q2'26) Change over 8 quarters+2.7M Share of the company11.840% ARCH Venture Management, LLC's full portfolio →

FMR LLC

2.6M

% of company

11.35%

Change vs last qtr

−114.4K (−4.2%)

Held since

2024

ARCH Venture Management, LLC

2.7M

% of company

11.84%

Change vs last qtr

NEW

Held since

Q2 '26

28 more super investors behind a free account

See every manager holding Boundless Bio, Inc., how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting BOLD on Form N-PORT; together they hold 9.4% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
FG Fidelity Growth Company Fund Fidelity Mt. Vernon Street Trust	$2.53M	899.2K	3.95%	0.00%	August 31, 2026
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$1.11M	445.2K	1.96%	0.00%	June 30, 2026

Fidelity Growth Company Fund

Fidelity Mt. Vernon Street Trust

Position value

$2.53M

% of company

3.95%

% of the fund

0.00%

As of

August 31, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$1.11M

% of company

1.96%

% of the fund

0.00%

As of

June 30, 2026

10 more funds behind a free account

See every fund holding Boundless Bio, Inc. and how much of the fund the position is.

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