Atrium Therapeutics, Inc. (RNA) Ownership
RNA ownership summary
as of October 17, 2026- Institutions
- 84.3% of shares outstanding
- Insiders
- 4.16% of shares outstanding
- Shares outstanding
- 17.1M
- Float
- 15.0M shares available to trade
- Short interest
- 6.62% 3.4M shares short
- Days to cover
- 8.40 short interest down 0.1% vs prior month
- Institutions 84.34%
- Insiders 4.16%
- Other investors 11.50%
RNA top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | CIBC Bancorp USA Inc. | 0.00% | — | — | −10,871 (−100.0%) | March 31, 2026 |
| 2 | Arizona State Retirement System | 0.00% | — | — | −30,510 (−100.0%) | March 31, 2026 |
| 3 | Capital Analysts Inc. | 0.00% | — | — | −143 (−100.0%) | March 31, 2026 |
| 4 | Acadian Asset Management LLC | 0.00% | — | — | −37,523 (−100.0%) | March 31, 2026 |
| 5 | Carmignac Gestion | 0.00% | — | — | −57,938 (−100.0%) | March 31, 2026 |
| 6 | Allianz Asset Management AG | 0.00% | — | — | −309,887 (−100.0%) | March 31, 2026 |
| 7 | Cinctive Capital Management LP | 0.00% | — | — | −50,000 (−100.0%) | March 31, 2026 |
| 8 | ARP AMERICAS LLC | 0.00% | — | — | −162,880 (−100.0%) | March 31, 2026 |
| 9 | CIBC Global Asset Management Inc | 0.00% | — | — | −5,432 (−100.0%) | March 31, 2026 |
| 10 | CI Private Wealth LLC | 0.00% | — | — | −19,100 (−100.0%) | March 31, 2026 |
| 11 | Abacus Wealth Partners, LLC | 0.00% | — | — | −8,466 (−100.0%) | March 31, 2026 |
| 12 | Abel Hall LLC | 0.00% | — | — | −8,596 (−100.0%) | March 31, 2026 |
| 13 | Atlantic Private Wealth, LLC | 0.00% | — | — | −5 (−100.0%) | March 31, 2026 |
| 14 | Artia Global Partners LP | 0.00% | — | — | −60,100 (−100.0%) | March 31, 2026 |
| 15 | Capula Management Ltd | 0.00% | — | — | −389,566 (−100.0%) | March 31, 2026 |
| 16 | AQR Capital Management LLC | 0.00% | — | — | −14,149 (−100.0%) | March 31, 2026 |
| 17 | Amalgamated Financial Corp | 0.00% | — | — | −3,637 (−100.0%) | March 31, 2026 |
| 18 | ABC arbitrage SA | 0.00% | — | — | −93,300 (−100.0%) | March 31, 2026 |
| 19 | Ameriprise Financial Inc | 0.00% | — | — | −13,164 (−100.0%) | March 31, 2026 |
| 20 | Burkehill Global Management, LP | 0.00% | — | — | −60,000 (−100.0%) | March 31, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 0 holders added 0 shares and 20 cut 1.3M.
RNA top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Russell 2000 ETF | 1.79% | 2.8M | $21.3M | +2.8M (0.0%) | February 28, 2026 |
| 2 | BlackRock Event Driven Equity Instl | 1.13% | 1.8M | $13.5M | +1.8M (0.0%) | January 31, 2026 |
| 3 | iShares Russell 2000 Growth ETF | 0.57% | 888K | $6.8M | +887,885 (0.0%) | February 28, 2026 |
| 4 | NexPoint Merger Arbitrage Z | 0.53% | 824K | $6.3M | +824,400 (0.0%) | December 31, 2025 |
| 5 | The Merger Fund A | 0.53% | 818K | $6.3M | +817,749 (0.0%) | December 31, 2025 |
| 6 | Vanguard Russell 2000 ETF | 0.36% | 551K | $4.2M | −17,711 (−3.1%) | January 31, 2026 |
| 7 | BSF Global Event Driven Z2 USD | 0.29% | 443K | $3.4M | +104,664 (+30.9%) | December 31, 2025 |
| 8 | PICTON Arbitrage Plus Alternative Fund F | 0.22% | 346K | $2.7M | +34,100 (+10.9%) | December 31, 2025 |
| 9 | Vanguard Health Care ETF | 0.21% | 330K | $2.5M | −120 (−0.0%) | January 31, 2026 |
| 10 | Schwab Small Cap Index | 0.19% | 292K | $2.2M | +3,923 (+1.4%) | January 31, 2026 |
| 11 | iShares Russell 2000 Small-Cap Idx Instl | 0.12% | 190K | $1.5M | +132,757 (+229.9%) | January 31, 2026 |
| 12 | Stt Strt SPDR® Russell2000 US SmCapETF | 0.12% | 187K | $1.4M | +155,849 (+503.0%) | January 31, 2026 |
| 13 | iShares Core S&P Total US Stock Mkt ETF | 0.11% | 178K | $1.4M | — | February 28, 2026 |
| 14 | Nuveen Small Cap Blend Idx R6 | 0.09% | 141K | $1.1M | — | January 31, 2026 |
| 15 | EQ/2000 Managed Volatility IB | 0.08% | 125K | $959,080 | — | January 31, 2026 |
| 16 | BlackRock Advantage Small Cap Core Instl | 0.08% | 117K | $894,775 | +228 (+0.2%) | January 31, 2026 |
| 17 | Return Stacked Bonds & Mrg Arbtrg ETF | 0.07% | 106K | $811,248 | +105,769 (0.0%) | February 27, 2026 |
| 18 | BlackRock Health Sciences Opps Inv A | 0.06% | 100K | $768,749 | — | January 31, 2026 |
| 19 | Vanguard Russell 2000 Growth ETF | 0.06% | 98K | $751,177 | +4,137 (+4.4%) | January 31, 2026 |
| 20 | Nuveen Equity Index R6 | 0.06% | 94K | $724,807 | — | January 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
RNA insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-01-21 | Michael F Maclean | Sell | $72.45 | 4,542 | $329,068 |
| 2026-01-21 | Arthur A Levin | Sell | $72.45 | 1,758 | $127,367 |
| 2026-01-21 | W. Michael Flanagan | Sell | $72.45 | 6,534 | $473,388 |
| 2026-01-21 | Teresa Mccarthy | Sell | $72.45 | 2,929 | $212,206 |
| 2026-01-21 | Steven George Hughes | Sell | $72.45 | 4,895 | $354,643 |
| 2026-01-21 | Sarah Boyce | Sell | $72.45 | 14,387 | $1.0M |
| 2026-01-07 | Charles Calderaro III | Sell | $72.23 | 3,727 | $269,201 |
| 2026-01-07 | John B Moriarty | Sell | $72.23 | 2,374 | $171,474 |
| 2026-01-07 | Michael F Maclean | Sell | $72.23 | 1,974 | $142,582 |
| 2026-01-07 | Sarah Boyce | Sell | $72.23 | 8,576 | $619,444 |
| 2026-01-07 | Steven George Hughes | Sell | $72.23 | 2,373 | $171,402 |
| 2026-01-07 | Teresa Mccarthy | Sell | $72.23 | 1,965 | $141,932 |
| 2026-01-07 | W. Michael Flanagan | Sell | $72.23 | 2,373 | $171,402 |
| 2025-10-22 | Steven George Hughes | Sell | $47.54 | 2,209 | $105,016 |
| 2025-10-15 | Teresa Mccarthy | Sell | $50.15 | 20,000 | $1.0M |
| 2025-10-03 | Eric Mosbrooker | Sell | $45.38 | 6,562 | $297,784 |
| 2025-09-22 | Steven George Hughes | Sell | $40.58 | 2,208 | $89,601 |
| 2025-09-05 | Sarah Boyce | Sell | $49.95 | 50,000 | $2.5M |
| 2025-09-05 | Troy Edward Wilson | Sell | $50.00 | 29,500 | $1.5M |
| 2025-09-03 | Eric Mosbrooker | Sell | $47.07 | 6,563 | $308,920 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
RNA shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns RNA
Institutional investors own 84.3% of Atrium Therapeutics's shares and insiders 4.16%. The largest holder is CIBC Bancorp USA Inc. with 0.00% of the shares (0), as of March 31, 2026. Among the top 20 institutions, 0 added shares and 20 reduced their stake in the latest filings. Short interest is 6.62% of the float, or 8.40 days of average trading volume. The share count fell 67.6% since 2014.
Related: RNA analyst forecast, RNA key metrics. See the RNA stock overview for the latest quote and news.
RNA ownership FAQ
Who owns the most Atrium Therapeutics stock?
The largest shareholders of Atrium Therapeutics are CIBC Bancorp USA Inc. (0.00%), Arizona State Retirement System (0.00%), Capital Analysts Inc. (0.00%), Acadian Asset Management LLC (0.00%), Carmignac Gestion (0.00%).
What percentage of Atrium Therapeutics is owned by institutions?
Institutions hold 84.3% of Atrium Therapeutics's shares outstanding; insiders hold 4.16%.
Which funds own Atrium Therapeutics?
The largest fund holders of Atrium Therapeutics are iShares Russell 2000 ETF (1.79%), BlackRock Event Driven Equity Instl (1.13%), iShares Russell 2000 Growth ETF (0.57%), NexPoint Merger Arbitrage Z (0.53%), The Merger Fund A (0.53%).
What is Atrium Therapeutics's short interest?
3.4M shares of Atrium Therapeutics were sold short, 6.62% of the float; at the average daily volume it would take 8.40 days to cover.
Are insiders buying or selling Atrium Therapeutics?
Of the latest 20 reported insider transactions in Atrium Therapeutics (since September 3, 2025), 0 were purchases and 20 were sales.
How many shares of Atrium Therapeutics are outstanding?
Atrium Therapeutics has 17.1M shares outstanding, of which 15.0M are in the public float.