ATRIUM THERAPEUTICS INC RNA
COM · Common Stock · CUSIP 04965N104
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersSan Diego, CA
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($46.6k this quarter). Holder counts are more reliable. Implied quarter-end price ≈ $13.45. Options: 4 managers hold calls ($934.8k notional), 4 hold puts ($11.9m).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q1 2026 | 163 |
| Q2 2026 | 155 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $0 | $0 | — |
| Q4 2025 | $0 | $0 | — |
| Q1 2026 | $968.0k | $15.6m | 16.12 |
| Q2 2026 | $934.8k | $11.9m | 12.77 |
Biggest buyers
| CRCM LP | New | +1.3m |
| Sessa Capital IM, L.P. | Added | +948.6k |
| Arbiter Partners Capital Management LLC | Added | +292.6k |
| CANTOR FITZGERALD, L. P. | Added | +278.2k |
| BlackRock, Inc. | Added | +242.2k |
| AQR CAPITAL MANAGEMENT LLC | New | +172.2k |
| TWO SIGMA INVESTMENTS, LP | Added | +166.9k |
| DAFNA Capital Management LLC | New | +128.0k |
| Anson Funds Management LP | New | +125.0k |
| VANGUARD CAPITAL MANAGEMENT LLC | Added | +104.0k |
Biggest sellers
| RA CAPITAL MANAGEMENT, L.P. | Sold out | -864.1k |
| Pentwater Capital Management LP | Sold out | -602.6k |
| FARALLON CAPITAL MANAGEMENT, L.L.C. | Sold out | -349.4k |
| Bellevue Group AG | Sold out | -263.1k |
| VANGUARD PORTFOLIO MANAGEMENT LLC | Reduced | -243.2k |
| AQR Arbitrage LLC | Sold out | -179.7k |
| Balyasny Asset Management L.P. | Reduced | -129.2k |
| MORGAN STANLEY | Reduced | -123.1k |
| Squarepoint Ops LLC | Reduced | -84.7k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | Reduced | -83.6k |
Biggest calls
| Caption Management, LLC | Unchanged | $817.8k60.8k shares |
| Walleye Trading LLC | Reduced | $67.2k5.0k shares |
| GROUP ONE TRADING LLC | Reduced | $49.8k3.7k shares |
| FNY Investment Advisers, LLC | Reduced | $037 shares |
Biggest puts
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $11.3m840.6k shares |
| GROUP ONE TRADING LLC | Unchanged | $353.7k26.3k shares |
| Walleye Trading LLC | Reduced | $281.1k20.9k shares |
| GLAZER CAPITAL, LLC | Reduced | $0201 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| Sessa Capital IM, L.P. 13G · institution new · filed 2026-08-14 | 8.8% |
| PRICE T ROWE ASSOCIATES INC /MD/ 13G · institution -1.4 pts · filed 2026-08-14 | 8.6% |
| BlackRock, Inc. 13G · institution +1.4 pts · filed 2026-07-27 | 6.6% |
Fell to 5% or below in the last year: RA CAPITAL MANAGEMENT, L.P. (0.0%, 2026-08-14)
Insider purchases and sales since 1 Apr 2026
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
None reported since 1 Apr 2026.
Holders, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| Sessa Capital IM, L.P. 0.35% of their portfolio | 1.5m $20.2m | Added +948.6k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 1.5m $19.8m | Reduced -80.2k |
| BlackRock, Inc. 0.00% of their portfolio | 1.4m $19.5m | Added +242.2k |
| CRCM LP 5.68% of their portfolio | 1.3m $17.3m | New |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 730.8k $9.8m | Added +104.0k |
| TIG Advisors, LLC 0.35% of their portfolio | 561.5k $7.6m | Reduced -46.0k |
| Arbiter Partners Capital Management LLC 1.95% of their portfolio | 522.6k $7.0m | Added +292.6k |
| CANTOR FITZGERALD, L. P. 0.07% of their portfolio | 513.8k $6.9m | Added +278.2k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 386.9k $5.2m | Added +67.1k |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 345.5k $4.6m | Added +166.9k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 310.3k $4.2m | Reduced -39.6k |
| 683 Capital Management, LLC 0.37% of their portfolio | 300.0k $4.0m | Unchanged |
| STATE STREET CORP 0.00% of their portfolio | 271.8k $3.7m | Added +14.7k |
| Slotnik Capital, LLC 0.89% of their portfolio | 237.6k $3.2m | Added +56.7k |
| Weiss Asset Management LP 0.03% of their portfolio | 219.7k $3.0m | Reduced -21.0k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 200.6k $2.7m | Added +9.7k |
| Schonfeld Strategic Advisors LLC 0.01% of their portfolio | 199.2k $2.7m | Added +36.4k |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 172.2k $2.3m | New |
| NEXPOINT ASSET MANAGEMENT, L.P. 0.13% of their portfolio | 150.0k $2.0m | Unchanged |
| Polar Asset Management Partners Inc. 0.04% of their portfolio | 150.0k $2.0m | Added +80.0k |
| Squarepoint Ops LLC 0.00% of their portfolio | 146.7k $2.0m | Reduced -84.7k |
| Bracebridge Capital, LLC 0.41% of their portfolio | 139.2k $1.9m | Unchanged |
| NOMURA HOLDINGS INC 0.01% of their portfolio | 137.4k $1.8m | Added +14 |
| Yakira Capital Management, Inc. 0.53% of their portfolio | 133.0k $1.8m | Added +6.4k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 132.8k $1.8m | Reduced -3.4k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 130.2k $1.8m | Added +13.6k |
| TUDOR INVESTMENT CORP ET AL 0.01% of their portfolio | 129.6k $1.7m | Added +58.2k |
| DAFNA Capital Management LLC 0.33% of their portfolio | 128.0k $1.7m | New |
| Creek Drive Management Group LLC 1.06% of their portfolio | 127.6k $1.7m | Added +7.6k |
| NORGES BANK 0.00% of their portfolio | 126.6k $1.7m | Not comparable |
| Anson Funds Management LP 0.15% of their portfolio | 125.0k $1.7m | New |
| NORTHERN TRUST CORP 0.00% of their portfolio | 119.8k $1.6m | Added +21.2k |
| ExodusPoint Capital Management, LP 0.01% of their portfolio | 117.3k $1.6m | Added +39.8k |
| Trium Capital LLP 0.96% of their portfolio | 113.3k $1.5m | Not comparable |
| TD Asset Management Inc 0.00% of their portfolio | 111.2k $1.5m | Unchanged |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 110.0k $1.5m | Added +14.8k |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 109.8k $1.5m | Added +89.9k |
| Athos Capital Ltd 0.52% of their portfolio | 108.0k $1.5m | Unchanged |
| AWM Investment Company, Inc. 0.13% of their portfolio | 107.5k $1.4m | Added +57.5k |
| Balyasny Asset Management L.P. 0.00% of their portfolio | 105.9k $1.4m | Reduced -129.2k |
| Marble Bar Asset Management LLP 0.97% of their portfolio | 103.8k $1.4m | Reduced -43.2k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 101.2k $1.4m | Reduced -243.2k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.00% of their portfolio | 100.0k $1.3m | Reduced -83.6k |
| BlueCrest Capital Management Ltd 0.06% of their portfolio | 100.0k $1.3m | New |
| CREDIT INDUSTRIEL ET COMMERCIAL 0.13% of their portfolio | 89.7k $1.2m | Added +66.7k |
| Groupe la Francaise 0.01% of their portfolio | 80.3k $1.1m | Added +50.6k |
| FIL Ltd 0.00% of their portfolio | 76.5k $1.0m | Reduced -2.0k |
| Caption Management, LLC 0.04% of their portfolio | 75.3k $1.0m | Reduced -28.3k |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 67.6k $909.7k | Reduced -42.3k |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio | 62.9k $845.4k | Added +474 |
| ADAR1 Capital Management, LLC 0.04% of their portfolio | 57.7k $775.9k | Unchanged |
| FRANKLIN RESOURCES INC 0.00% of their portfolio | 56.7k $762.6k | New |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.00% of their portfolio | 54.0k $726.2k | New |
| ODDO BHF ASSET MANAGEMENT SAS 0.03% of their portfolio | 45.1k $606.5k | Unchanged |
| CAXTON ASSOCIATES LLP 0.01% of their portfolio | 44.2k $594.9k | Unchanged |
| ALETHEA CAPITAL MANAGEMENT, LLC 0.24% of their portfolio | 43.8k $588.5k | Unchanged |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 42.0k $564.5k | Unchanged |
| MORGAN STANLEY 0.00% of their portfolio | 41.9k $564.1k | Reduced -123.1k |
| Saba Capital Management, L.P. 0.02% of their portfolio | 39.6k $533.2k | Unchanged |
| Bank of New York Mellon Corp 0.00% of their portfolio | 39.3k $527.9k | Reduced -4.4k |
| Y-Intercept (Hong Kong) Ltd 0.01% of their portfolio | 35.1k $472.1k | New |
| KENNEDY CAPITAL MANAGEMENT LLC 0.01% of their portfolio | 35.0k $470.5k | Added +1.0k |
| FMR LLC 0.00% of their portfolio | 33.5k $451.0k | Added +4.2k |
| Moran Wealth Management, LLC 0.01% of their portfolio | 33.3k $448.2k | New |
| BOUSSARD & GAVAUDAN GESTION SAS 0.02% of their portfolio | 32.8k $447.2k | First filing |
| LMR Partners LLP 0.00% of their portfolio | 32.5k $437.1k | Unchanged |
| LOS ANGELES CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 31.5k $423.4k | New |
| Nuveen, LLC 0.00% of their portfolio | 31.1k $417.9k | Added +5.8k |
| Jump Financial, LLC 0.00% of their portfolio | 31.0k $417.2k | New |
| Quantinno Capital Management LP 0.00% of their portfolio | 27.4k $368.8k | Added +15.0k |
| Twin Securities, Inc. 0.18% of their portfolio | 26.5k $356.7k | Reduced -23.4k |
| Odyssean, LLC 0.05% of their portfolio | 21.2k $285.6k | New |
| Brevan Howard Capital Management LP 0.00% of their portfolio | 20.8k $280.2k | Reduced -10.8k |
| Fractal Investments LLC 0.03% of their portfolio | 20.0k $269.0k | Unchanged |
| UBS Group AG 0.00% of their portfolio | 19.6k $263.2k | Reduced -30.2k |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND 0.00% of their portfolio | 18.6k $250.0k | Reduced -2.0k |
| Vestcor Inc 0.01% of their portfolio | 17.5k $235.0k | Unchanged |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 17.5k $234.7k | Added +6.0k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 17.1k $228.8k | Added +4.1k |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 16.6k $223.0k | Added +1.6k |
| BLUEFIN CAPITAL MANAGEMENT, LLC 0.06% of their portfolio | 16.0k $215.3k | New |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 15.0k $201.4k | New |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 15.0k $201.3k | Added +4.9k |
| Invesco Ltd. 0.00% of their portfolio | 14.2k $190.6k | Added +4.0k |
| Jupiter Topco LLC 0.00% of their portfolio | 13.8k $185.6k | First filing |
| AlphaCentric Advisors LLC 0.15% of their portfolio | 13.5k $181.3k | Added +192 |
| AXQ CAPITAL, LP 0.02% of their portfolio | 11.4k $153.0k | New |
| KESTRA PRIVATE WEALTH SERVICES, LLC 0.00% of their portfolio | 10.4k $139.5k | New |
| MetLife Investment Management, LLC 0.00% of their portfolio | 10.3k $138.3k | Added +1.4k |
| Corsicana & Co. 0.06% of their portfolio | 9.8k $132.1k | New |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 9.4k $128.1k | Reduced -2.6k |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 7.9k $106.3k | Reduced -366 |
| CITIGROUP INC 0.00% of their portfolio | 6.7k $89.9k | Added +6.0k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 6.6k $88.8k | Reduced -2.9k |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 5.6k $75.1k | Unchanged |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 4.5k $60.2k | Added +636 |
| Skandinaviska Enskilda Banken AB (publ) 0.00% of their portfolio | 4.4k $59.2k | New |
| Walleye Trading LLC 0.00% of their portfolio | 4.0k $53.5k | Added +350 |
| Quantbot Technologies LP 0.00% of their portfolio | 3.6k $48.6k | New |
| Erste Asset Management GmbH 0.00% of their portfolio | 3.6k $49.1k | Unchanged |