Companies / Atrium Therapeutics, Inc.

Atrium Therapeutics, Inc.

Nasdaq: RNACIK 2093101SAN DIEGO, CA

Ownership

17.1M shares outstanding · as of May 5, 2026
34.5%Institutions
Ownership
Institutions34.54%5,908,976
Public float65.46%11,196,667

% of common shares outstanding (exact, from the latest cover-page filing). Institutions are quarterly 13F snapshots; insiders reflect current officers & directors.

Insiders 11

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Insider% of sharesShares
Boyce SarahDirector
Gallagher Kathleen P.See Remarks · Director
Hoyos Rocio MartinChief Strategy Officer
Hughes Steven GeorgeChief Medical Officer
Kenney StephanieSee Remarks
Winslow Brendan R.Chief Financial Officer

Institutional holders 45

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Activity

InsidersInstitutions
What insiders are doing in this stock (Form 4).
DateActorActionSecurityValueShares ΔPosition afterImpact
Feb 27, 2026Skerjanec Simona
Director
GrantStock Option (Right to Buy)+20K
20,000
0.12% of shares
low
Feb 27, 2026Flanagan W. Michael
Director
GrantStock Option (Right to Buy)+20K
20,000
0.12% of shares
low
Feb 27, 2026Boyce Sarah
Director
GrantStock Option (Right to Buy)+20K
20,000
0.12% of shares
low
Feb 27, 2026Wilson Troy Edward
Director
GrantStock Option (Right to Buy)+20K
20,000
0.12% of shares
low
Feb 27, 2026Boess Carsten
Director
GrantStock Option (Right to Buy)+20K
20,000
0.12% of shares
low

5%+ ownership events

Schedule 13D / 13G
FilerStance% of classSharesDate
RA Capital Management, L.P.Passive13G

Securities

via CUSIP / OpenFIGI
SymbolTypeMarketCUSIPFIGI
RNA04965N104