13F Insight
DOSSIER · 13F Holders · Q1 2026Mega-capCrowded
RNA

ATRIUM THERAPEUTICS INC COM

153 institutions still hold ATRIUM THERAPEUTICS INC COM as of Q1 2026. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 04965N104·153 13F holders·last filed Mar 31, 2026
Market cap
—
▲ 1.5%
vs prior quarter
13F value held
$124M
67.0% inst. owned
of float
Holders
153
-60 QoQ
filers reporting
Activity
+94 / −85
+844 added · −813 reduced
this quarter
Concentration
13.02%
BlackRock, Inc. #1
top holder share
AI Holders Summary · Q1 2026

153 institutions reported RNA in Q1 2026. BlackRock, Inc. leads at 13.0% of the visible book. -60 net institutions QoQ — distribution reading.

Top holders

Sorted by position value. Source: SEC EDGAR 13F-HR filings.

#HolderValueShares% port.Quarter
01
BlackRock, Inc.
CIK 0002012383
$16M1.2M0.00%Q1 202602
SUSQUEHANNA INTERNATIONAL GROUP, LLP
CIK 0001446194· Market maker
$14M1.0M0.00%Q1 202603
RA CAPITAL MANAGEMENT, L.P.
CIK 0001346824
$12M864K0.12%Q1 202604
VANGUARD CAPITAL MANAGEMENT LLC
CIK 0002100119· Index
$8M627K0.00%Q1 202605
TIG Advisors, LLC
CIK 0001358253
$8M608K0.38%Q1 202606
Pentwater Capital Management LP
CIK 0001425851
$8M603K0.04%Q1 202607
O'Connor Alternative Investments LLC
CIK 0002081629
$8M578K0.66%Q1 202608
Sessa Capital IM, L.P.
CIK 0001595849
$7M551K0.13%Q1 202609
GOLDMAN SACHS GROUP INC
CIK 0000886982
$5M350K0.00%Q1 202610
FARALLON CAPITAL MANAGEMENT LLC
CIK 0000909661
$5M349K0.03%Q1 202611
Vanguard Portfolio Management
CIK 0002100121
$5M344K0.00%Q1 202612
GEODE CAPITAL MANAGEMENT, LLC
CIK 0001214717· Index
$4M320K0.00%Q1 202613
STATE STREET CORP
CIK 0000093751
$3M257K0.00%Q1 202614
Weiss Asset Management LP
CIK 0001357550
$3M241K0.05%Q1 202615
CANTOR FITZGERALD, L. P.
CIK 0001024896
$3M236K0.05%Q1 202616
BALYASNY ASSET MANAGEMENT L.P.
CIK 0001218710
$3M235K0.00%Q1 202617
Squarepoint Ops LLC
CIK 0001642575
$3M231K0.00%Q1 202618
Arbiter Partners Capital Management LLC
CIK 0001513193
$3M230K1.76%Q1 202619
Caption Management, LLC
CIK 0001706766
$3M204K0.02%Q1 202620
MILLENNIUM MANAGEMENT LLC
CIK 0001273087
$3M191K0.00%Q1 2026
Page 1 of 8
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