Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in ATOS held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | VANGUARD CAPITAL MANAGEMENT LLC | 349K | $1.8M | — | 4.054% | 0.00% |
| 2 | AMERIPRISE FINANCIAL INC | 255K | $1.3M | -93.3% | 2.963% | 0.00% |
| 3 | BlackRock, Inc. | 133K | $700K | -93.3% | 1.546% | 0.00% |
| 4 | RENAISSANCE TECHNOLOGIES LLC | 109K | $573K | -94.7% | 1.266% | 0.00% |
| 5 | GEODE CAPITAL MANAGEMENT, LLC | 97K | $511K | -92.9% | 1.127% | 0.00% |
| 6 | UBS Group AG | 92K | $484K | -76.4% | 1.069% | 0.00% |
| 7 | MILLENNIUM MANAGEMENT LLC | 67K | $351K | -94.6% | 0.775% | 0.00% |
| 8 | VANGUARD FIDUCIARY TRUST CO | 52K | $275K | — | 0.607% | 0.00% |
| 9 | STATE STREET CORP | 40K | $209K | -93.3% | 0.462% | 0.00% |
| 10 | NORTHERN TRUST CORP | 19K | $101K | -93.3% | 0.223% | 0.00% |
| 11 | MORGAN STANLEY | 16K | $85K | -73.7% | 0.188% | 0.00% |
| 12 | Vanguard Global Advisers, LLC | 3K | $16K | — | 0.036% | 0.00% |
| 13 | JONES FINANCIAL COMPANIES LLLP | 2K | $10K | +194.4% | 0.024% | 0.00% |
| 14 | Tower Research Capital LLC (TRC) | 863 | $5K | -78.4% | 0.010% | 0.00% |
| 15 | GROUP ONE TRADING, L.P. | 609 | $3K | -90.9% | 0.007% | 0.00% |
| 16 | ADVISOR GROUP HOLDINGS, INC. | 587 | $3K | -93.4% | 0.007% | 0.00% |
| 17 | ROYAL BANK OF CANADA | 644 | $3K | -31.7% | 0.007% | 0.00% |
| 18 | Rockefeller Capital Management L.P. | 353 | $2K | -92.9% | 0.004% | 0.00% |
| 19 | WELLS FARGO & COMPANY/MN | 296 | $2K | +256.6% | 0.003% | 0.00% |
| 20 | SBI Securities Co., Ltd. | 113 | $594 | -92.8% | 0.001% | 0.00% |
| 21 | HARBOUR INVESTMENTS, INC. | 110 | $579 | -93.4% | 0.001% | 0.00% |
| 22 | TD Waterhouse Canada Inc. | 103 | $525 | -93.4% | 0.001% | 0.00% |
| 23 | BNP PARIBAS ARBITRAGE, SA | 98 | $515 | -93.5% | 0.001% | 0.00% |
| 24 | North Star Investment Management Corp. | 80 | $421 | — | 0.001% | 0.00% |
| 25 | Allworth Financial LP | 46 | $242 | -93.5% | 0.001% | 0.00% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in ATOS — a direct measure of their conviction.
Filings activity in ATOS during Q1 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 30 | 53% | 30.75% | 28.55 pp | $7M | 48% |
| Q4 2025 | 64 | 3.0% | 59.30% | 18.70 pp | $13M | 24% |
| Q3 2025 | 66 | 20% | 78.00% | 4.91 pp | $17M | 5.9% |
| Q2 2025 | 83 | 1.2% | 82.91% | 6.44 pp | $18M | 7.2% |
| Q1 2025 | 84 | 2.3% | 89.35% | 39.39 pp | $19M | 31% |
| Q4 2024 | 86 | +0.0% | 128.74% | 66.86 pp | $27M | 34% |
| Q3 2024 | 86 | +12% | 195.60% | 4.39 pp | $41M | 11% |
| Q2 2024 | 77 | — | 199.99% | — | $46M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying ATOS stock.
Based on Q1 2026 13F filings, institutional ownership of Atossa Therapeutics, Inc. stands at 30.8%, held across 30 reporting institutions.
VANGUARD CAPITAL MANAGEMENT LLC is the largest reported institutional holder of ATOS, with approximately 349,096 shares worth $0.00B as of Q1 2026.
Yes — 2 widely-followed marquee investors appear among the top 25 institutional holders of ATOS, including RENAISSANCE TECHNOLOGIES LLC, MILLENNIUM MANAGEMENT LLC.
Our composite Smart Money Score for ATOS is 27 out of 100 (Bearish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
8 institutions opened new positions in ATOS during Q1 2026, while 42 fully exited. 6 added to existing positions and 16 trimmed.
ATOS institutional ownership fell by 28.55 percentage points quarter-over-quarter, with a net change of -34 holders.
The top 10 institutions account for 98.0% of all reported 13F value in ATOS, and the top 25 account for 100.0%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Atossa Therapeutics, Inc. (ATOS) Institutional Ownership