Companies / Atrium Therapeutics, Inc.
Atrium Therapeutics, Inc.
Nasdaq: RNACIK 2093101SAN DIEGO, CA
Ownership
17.1M shares outstanding · as of May 5, 2026
Ownership
| Institutions | 34.54% | 5,908,976 |
| Public float | 65.46% | 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
View all →| Insider | % of shares | Shares |
|---|---|---|
Boess CarstenDirector | — | — |
Boyce SarahDirector | — | — |
Flanagan W. MichaelDirector | — | — |
Gallagher Kathleen P.See Remarks · Director | — | — |
Hoyos Rocio MartinChief Strategy Officer | — | — |
Hughes Steven GeorgeChief Medical Officer | — | — |
Kenney StephanieSee Remarks | — | — |
Skerjanec SimonaDirector | — | — |
Wilson Troy EdwardDirector | — | — |
Winslow Brendan R.Chief Financial Officer | — | — |
Institutional holders 45
View all →| Holder | Value | % of shares |
|---|---|---|
| $19.47M | 8.46% | |
| $11.55M | 5.05% | |
| $8.12M | 3.55% | |
| $4.28M | 1.87% | |
| $3.66M | 1.59% | |
| $3.22M | 1.41% | |
| $3.15M | 1.38% | |
| $3.14M | 1.37% | |
| $2.55M | 1.12% | |
| $2.45M | 1.07% |
Activity
Jun 30, 2026View all →
InsidersInstitutions
Who's accumulating and trimming this stock (13F).| Date | Actor | Action | Security | Value | Shares Δ | Position after | Impact |
|---|---|---|---|---|---|---|---|
| Q2 2026 as of | BlackRock, Inc. 13F manager | New | Common stock | $19.47M | +1.4M | 1,447,476 8.46% of shares | medium |
| Q1 2026 as of | RA Capital Management, L.P. 13F manager | New | Common stock | $11.55M | +864K | 864,102 5.05% of shares | medium |
| Q1 2026 as of | TIG Advisors, LLC 13F manager | New | Common stock | $8.12M | +608K | 607,552 3.55% of shares | medium |
| Q1 2026 as of | Geode Capital Management, LLC 13F manager | New | Common stock | $4.28M | +320K | 319,831 1.87% of shares | low |
| Q2 2026 as of | State Street Corporation 13F manager | New | Common stock | $3.66M | +272K | 271,762 1.59% of shares | low |
| Q1 2026 as of | Weiss Asset Management LP 13F manager | New | Common stock | $3.22M | +241K | 240,701 1.41% of shares | low |
| Q1 2026 as of | Cantor Fitzgerald, L. P. 13F manager | New | Common stock | $3.15M | +236K | 235,637 1.38% of shares | low |
| Q1 2026 as of | Balyasny Asset Management L.P. 13F manager | New | Common stock | $3.14M | +235K | 235,115 1.37% of shares | low |
5%+ ownership events
Schedule 13D / 13G
| Filer | Stance | % of class |
|---|---|---|
| RA Capital Management, L.P. | Passive13G | — |
Securities
via CUSIP / OpenFIGI
| Symbol | Type | CUSIP |
|---|---|---|
| RNA | — | 04965N104 |