Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
179 institutional managers reported holding ATAI for the quarter ended Mar 31, 2026. Together they hold about 44% of shares outstanding; the top 10 hold 29%. 70 opened new positions; 30 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| Vanguard Group | 13.26M | 5.85% | $46.8M | added +8533.9% | 2022 Q2 |
| Deep Track Capital, LP | 12.00M | 5.30% | $42.4M | added +156.6% | 2025 Q4 |
| UBS | 7.69M | 3.40% | $27.2M | added +3950.3% | 2018 Q3 |
| BlackRock | 6.84M | 3.02% | $24.1M | added +143% | 2021 Q4 |
| Adage Capital Partners GP, L.l.c. | 5.64M | 2.49% | $19.9M | trimmed -20.3% | 2025 Q2 |
| Susquehanna International Group | 5.31M | 2.34% | $18.7M | added +741.8% | 2021 Q4 |
| Millennium Management | 4.36M | 1.93% | $15.4M | opened | 2021 Q2 |
| Morgan Stanley | 3.85M | 1.70% | $13.6M | trimmed -20.1% | 2019 Q2 |
| Candriam S.c.a. | 3.09M | 1.36% | $10.9M | opened | 2026 Q1 |
| Qube Research & Technologies LTD | 2.89M | 1.28% | $10.2M | added +125.7% | 2025 Q3 |
| Foresite Capital Management VI LLC (focused) | 2.75M | 1.21% | $9.7M | unchanged | 2025 Q4 |
| Geode Capital | 2.51M | 1.11% | $8.9M | opened | 2021 Q2 |
| Marshall Wace | 2.36M | 1.04% | $8.3M | trimmed -11.6% | 2025 Q2 |
| RTW Investments, LP | 2.00M | 0.88% | $7.1M | unchanged | 2025 Q4 |
| Two Sigma | 1.98M | 0.87% | $7.0M | added +40.1% | 2021 Q4 |
| Newtyn Management, LLC (focused) | 1.78M | 0.79% | $6.3M | opened | 2026 Q1 |
| Eagle Health Investments LP (focused) | 1.71M | 0.76% | $6.0M | added +1.8% | 2025 Q4 |
| Charles Schwab Investment Management | 1.18M | 0.52% | $4.2M | opened | 2026 Q1 |
| State Street | 1.14M | 0.51% | $4.0M | added +296.9% | 2021 Q4 |
| Moore Capital | 952.4k | 0.42% | $3.4M | opened | 2025 Q1 |
| Adar1 Capital Management, LLC | 913.2k | 0.40% | $3.2M | unchanged | 2025 Q3 |
| Bank OF America CORP /DE/ | 819.7k | 0.36% | $2.9M | added +993.8% | 2019 Q1 |
| Brown University (focused) | 718.5k | 0.32% | $2.5M | unchanged | 2021 Q2 |
| CenterBook Partners LP | 707.4k | 0.31% | $2.5M | trimmed -9.4% | 2025 Q3 |
| Point72 | 664.7k | 0.29% | $2.3M | trimmed -29% | 2025 Q4 |
| Woodline Partners LP | 600.0k | 0.27% | $2.1M | unchanged | 2024 Q3 |
| AdvisorShares Investments LLC | 567.6k | 0.25% | $2.0M | added +3.5% | 2021 Q3 |
| Sumitomo Mitsui Trust Group, INC. | 567.6k | 0.25% | $2.0M | opened | 2025 Q3 |
| Amova Asset Management Americas, INC. | 567.6k | 0.25% | $2.0M | added +23% | 2025 Q3 |
| Man Group | 543.5k | 0.24% | $1.9M | added +127.6% | 2025 Q3 |
| Northern Trust | 538.0k | 0.24% | $1.9M | added +333.7% | 2025 Q4 |
| Goldman Sachs | 520.9k | 0.23% | $1.8M | trimmed -44% | 2021 Q4 |
| Squarepoint Ops LLC | 469.7k | 0.21% | $1.7M | added +32.4% | 2025 Q3 |
| OP Asset Management LTD | 423.7k | 0.19% | $1.5M | opened | 2026 Q1 |
| Orbimed Advisors LLC | 347.0k | 0.15% | $1.2M | opened | 2025 Q3 |
| Swiss National Bank | 325.9k | 0.14% | $1.2M | unchanged | 2025 Q4 |
| Axon Capital LP (focused) | 305.8k | 0.14% | $1.1M | opened | 2026 Q1 |
| Boussard & Gavaudan Investment Management LLP | 295.3k | 0.13% | $1.0M | opened | 2026 Q1 |
| Stableford Capital II LLC | 286.3k | 0.13% | $1.0M | trimmed -1.8% | 2025 Q4 |
| Jefferies Financial Group INC. | 275.9k | 0.12% | $974k | opened | 2026 Q1 |
| Brummer Multi-Strategy AB (focused) | 275.4k | 0.12% | $972k | added +17.2% | 2025 Q4 |
| Jain Global LLC | 244.2k | 0.11% | $862k | added +824.1% | 2025 Q4 |
| Brevan Howard Capital Management LP | 236.9k | 0.10% | $836k | opened | 2026 Q1 |
| Citadel Advisors | 231.4k | 0.10% | $817k | trimmed -85.7% | 2021 Q2 |
| Verdad Advisers, LP | 227.7k | 0.10% | $804k | opened | 2026 Q1 |
| Catalio Capital Management, LP (focused) | 196.9k | 0.09% | $695k | unchanged | 2024 Q4 |
| Hudson Bay Capital | 188.5k | 0.08% | $665k | opened | 2025 Q3 |
| IQ EQ Fund Management (IRELAND) LTD | 188.0k | 0.08% | $664k | added +54.9% | 2025 Q3 |
| Burkehill Global Management, LP | 185.0k | 0.08% | $653k | unchanged | 2025 Q4 |
| BIT Capital GmbH | 182.6k | 0.08% | $644k | opened | 2025 Q1 |
Largest 50 of 179 shown; the full ranked, searchable register is at boothcheck.com/holders/ATAI. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.