$RNA

$8.32 +$0.27 (3.35%) Close

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

Ownership

13F as of Q2 2026 · 17.1M shares outstanding

Who owns RNA?

By type of holder

Institutions 83.8% Insiders 3.0% Everyone else 13.2%

Concentration Top 10 holders own 45.0%

Price T Rowe Associates Inc /MD/ 8.6% · Sessa Capital IM, L.P. 8.8%

Institutional ownership

83.8%

-2.9 pts vs last qtr

Institutional holders

154

-9 vs last qtr

Net shares bought

−502.1K

by institutions in Q2 2026

New / sold out

39 / 48

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

Sessa Capital IM, L.P. +948.6K
CRCM LP NEW +641.5K

Biggest sellers in Q2 2026

Ra Capital Management, L.P. SOLD OUT −864.1K
Pentwater Capital Management LP SOLD OUT −602.6K

Who is planning to sell?

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

Is your stake being diluted?

There are not yet two fiscal years of reported share counts for Atrium Therapeutics Inc.

How patient are the owners?

Institutional shares by how long they've been held

5+ years0% 3–5 years0% 1–3 years0% Under 1 year100%

Quarterly turnover

29.0%

of institutional shares changed hands

Top 10 managers, median time held

1 quarter

Super Investors

Investment managers reporting RNA on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
PT Price T Rowe Associates Inc /MD/	1.5M	8.61%	−80.2K (−5.2%)	Q1 '26	0.0%
Shares held by quarter Peak holding1.6M (Q1'26) Change over 8 quarters+1.5M Share of the company8.610% Price T Rowe Associates Inc /MD/'s full portfolio →
SC Sessa Capital IM, L.P.	1.5M	8.77%	+948.6K (+172.0%)	Q1 '26	0.3%
Shares held by quarter Peak holding1.5M (Q2'26) Change over 8 quarters+1.5M Share of the company8.770% Sessa Capital IM, L.P.'s full portfolio →

Price T Rowe Associates Inc /MD/

1.5M

% of company

8.61%

Change vs last qtr

−80.2K (−5.2%)

Held since

Q1 '26

Sessa Capital IM, L.P.

1.5M

% of company

8.77%

Change vs last qtr

+948.6K (+172.0%)

Held since

Q1 '26

28 more super investors behind a free account

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

Institutional Funds

Mutual funds and ETFs reporting RNA on Form N-PORT; together they hold 24.4% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
TR T. Rowe Price Health Sciences Fund, Inc. T. Rowe Price Health Sciences Fund, Inc.	$7.62M	566.4K	3.31%	0.06%	June 30, 2026
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$6.97M	518.4K	3.03%	0.00%	June 30, 2026

T. Rowe Price Health Sciences Fund, Inc.

Position value

$7.62M

% of company

3.31%

% of the fund

0.06%

As of

June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$6.97M

% of company

3.03%

% of the fund

0.00%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding Atrium Therapeutics Inc and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
BS Boyce Sarah Insider	138.7K	0.81%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company0.810% Boyce Sarah's insider activity →
GK Gallagher Kathleen P. Insider	119.7K	0.70%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company0.700% Gallagher Kathleen P.'s insider activity →

Boyce Sarah

Insider

138.7K

% of company

0.81%

Change vs last qtr

—

Held since

—

Gallagher Kathleen P.

Insider

119.7K

% of company

0.70%

Change vs last qtr

—

Held since

—

9 more holders behind a free account

See every insider and 5%+ holder of Atrium Therapeutics Inc.

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