Who owns ATAI (ATAI)
Which tracked institutional funds hold ATAI, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ATAI company fundamentals →
Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
30 tracked funds added or opened ATAI while 28 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
ATAI’s largest tracked holder by dollar value, Deep Track Capital, LP, sizes it at 0.9% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.9pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in ATAI divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 185 tracked filers holding ATAI, 113 increased or opened the position and 60 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in ATAI between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 19
- VANGUARD CAPITAL MANAGEMENT LLC$42M
- UBS Group AG$26M
- MILLENNIUM MANAGEMENT LLC$15M
- Candriam S.C.A.$11M
- GEODE CAPITAL MANAGEMENT, LLC$9M
- Newtyn Management, LLC$6M
Full exits 10
- ARK Investment Management LLC$14M
- Ally Bridge Group (NY) LLC$7M
- HRT FINANCIAL LP$6M
- JANE STREET GROUP, LLC$3M
- PRICE T ROWE ASSOCIATES INC /MD/$2M
- GROUP ONE TRADING LLC$1M
Largest adds
- Deep Track Capital, LP$23M
- SUSQUEHANNA INTERNATIONAL GROUP, LLP$16M
- BlackRock, Inc.$13M
- Qube Research & Technologies Ltd$5M
- STATE STREET CORP$3M
- BANK OF AMERICA CORP /DE/$3M
Largest trims
- ADAGE CAPITAL PARTNERS GP, L.L.C.$9M
- AMERIPRISE FINANCIAL INC$7M
- MORGAN STANLEY$6M
- CITADEL ADVISORS LLC$6M
- MARSHALL WACE, LLP$3M
- GOLDMAN SACHS GROUP INC$2M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| Deep Track Capital, LP added | 12,000,000 | $42M | 10.7% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 11,761,398 | $42M | 10.5% | 2026-Q1 |
| UBS Group AG trimmed | 7,426,867 | $26M | 6.7% | 2026-Q1 |
| BlackRock, Inc. added | 6,835,300 | $24M | 6.1% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed | 5,642,758 | $20M | 5.1% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 5,286,326 | $19M | 4.7% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 4,364,096 | $15M | 3.9% | 2026-Q1 |
| MORGAN STANLEY trimmed | 3,852,772 | $14M | 3.5% | 2026-Q1 |
| Candriam S.C.A. new | 3,086,379 | $11M | 2.8% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 2,891,942 | $10M | 2.6% | 2026-Q1 |
| Foresite Capital Management VI LLC | 2,750,000 | $10M | 2.5% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 2,509,974 | $9M | 2.2% | 2026-Q1 |
| MARSHALL WACE, LLP trimmed | 2,364,446 | $8M | 2.1% | 2026-Q1 |
| RTW INVESTMENTS, LP | 2,000,000 | $7M | 1.8% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 1,975,552 | $7M | 1.8% | 2026-Q1 |
| Newtyn Management, LLC added | 1,781,703 | $6M | 1.6% | 2026-Q1 |
| Eagle Health Investments LP added | 1,709,359 | $6M | 1.5% | 2026-Q1 |
| Arete Wealth Advisors, LLC added | 16,395 | $5M | 1.2% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 1,256,731 | $4M | 1.1% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC new | 1,181,583 | $4M | 1.1% | 2026-Q1 |
| STATE STREET CORP added | 1,144,355 | $4M | 1.0% | 2026-Q1 |
| MOORE CAPITAL MANAGEMENT, LP | 952,380 | $3M | 0.9% | 2026-Q1 |
| ADAR1 Capital Management, LLC | 913,242 | $3M | 0.8% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 819,664 | $3M | 0.7% | 2026-Q1 |
| Brown University | 718,500 | $3M | 0.6% | 2026-Q1 |
| CenterBook Partners LP trimmed | 707,369 | $3M | 0.6% | 2026-Q1 |
| Point72 Asset Management, L.P. trimmed | 664,724 | $2M | 0.6% | 2026-Q1 |
| Woodline Partners LP | 600,000 | $2M | 0.5% | 2026-Q1 |
| AdvisorShares Investments LLC added | 567,587 | $2M | 0.5% | 2026-Q1 |
| Sumitomo Mitsui Trust Group, Inc. added | 567,576 | $2M | 0.5% | 2026-Q1 |
| Amova Asset Management Americas, Inc. added | 567,576 | $2M | 0.5% | 2026-Q1 |
| Man Group plc added | 543,515 | $2M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP added | 538,050 | $2M | 0.5% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 520,905 | $2M | 0.5% | 2026-Q1 |
| OP Asset Management Ltd new | 423,674 | $2M | 0.4% | 2026-Q1 |
| Squarepoint Ops LLC added | 469,693 | $2M | 0.4% | 2026-Q1 |
| ORBIMED ADVISORS LLC | 347,000 | $1M | 0.3% | 2026-Q1 |
| Swiss National Bank | 325,900 | $1M | 0.3% | 2026-Q1 |
| AXON CAPITAL LP new | 305,802 | $1M | 0.3% | 2026-Q1 |
| Boussard & Gavaudan Investment Management LLP new | 295,264 | $1M | 0.3% | 2026-Q1 |
| STABLEFORD CAPITAL II LLC trimmed | 286,282 | $1M | 0.3% | 2026-Q1 |
| Jefferies Financial Group Inc. new | 275,900 | $977K | 0.2% | 2026-Q1 |
| Brummer Multi-Strategy AB added | 275,409 | $975K | 0.2% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 266,000 | $942K | 0.2% | 2026-Q1 |
| Jain Global LLC added | 244,187 | $864K | 0.2% | 2026-Q1 |
| Brevan Howard Capital Management LP new | 236,942 | $839K | 0.2% | 2026-Q1 |
| Verdad Advisers, LP new | 227,670 | $806K | 0.2% | 2026-Q1 |
| Catalio Capital Management, LP | 196,858 | $697K | 0.2% | 2026-Q1 |
| Hudson Bay Capital Management LP added | 188,485 | $667K | 0.2% | 2026-Q1 |
| IQ EQ FUND MANAGEMENT (IRELAND) Ltd added | 188,033 | $666K | 0.2% | 2026-Q1 |
| Burkehill Global Management, LP | 185,000 | $655K | 0.2% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 192,514 | $655K | 0.2% | 2026-Q1 |
| BIT Capital GmbH added | 182,576 | $646K | 0.2% | 2026-Q1 |
| Rockefeller Capital Management L.P. | 179,000 | $634K | 0.2% | 2026-Q1 |
| Nuveen, LLC trimmed | 177,123 | $627K | 0.2% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 171,388 | $607K | 0.2% | 2026-Q1 |
| Shay Capital LLC trimmed | 164,142 | $581K | 0.1% | 2026-Q1 |
| Carrera Capital Advisors added | 137,560 | $487K | 0.1% | 2026-Q1 |
| Warm Springs Advisors Inc. new | 136,400 | $483K | 0.1% | 2026-Q1 |
| Catalyst Funds Management Pty Ltd new | 113,400 | $401K | 0.1% | 2026-Q1 |
| VANGUARD ASSET MANAGEMENT, Ltd new | 110,492 | $391K | 0.1% | 2026-Q1 |
| Legal & General Group Plc trimmed | 105,636 | $374K | 0.1% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 103,459 | $366K | 0.1% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 88,429 | $313K | 0.1% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 79,400 | $281K | 0.1% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC trimmed | 77,611 | $275K | 0.1% | 2026-Q1 |
| China Universal Asset Management Co., Ltd. added | 75,255 | $266K | 0.1% | 2026-Q1 |
| KLP KAPITALFORVALTNING AS | 69,800 | $247K | 0.1% | 2026-Q1 |
| WINTON GROUP Ltd new | 64,400 | $228K | 0.1% | 2026-Q1 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE new | 64,100 | $227K | 0.1% | 2026-Q1 |
| Virtus Investment Advisers, LLC new | 63,563 | $225K | 0.1% | 2026-Q1 |
| Fore Capital, LLC new | 60,000 | $212K | 0.1% | 2026-Q1 |
| Quantinno Capital Management LP | 58,246 | $206K | 0.1% | 2026-Q1 |
| ARK Investment Management LLC added | 3,305,997 | $14M | 3.4% | 2025-Q4 stale |
| Ally Bridge Group (NY) LLC trimmed | 1,713,105 | $7M | 1.8% | 2025-Q4 stale |
| HRT FINANCIAL LP added | 1,469,246 | $6M | 1.5% | 2025-Q4 stale |
| JANE STREET GROUP, LLC added | 759,996 | $3M | 0.8% | 2025-Q4 stale |
| FRED ALGER MANAGEMENT, LLC new | 488,855 | $3M | 0.7% | 2025-Q3 stale |
| PRICE T ROWE ASSOCIATES INC /MD/ trimmed | 465,352 | $2M | 0.5% | 2025-Q4 stale |
| GROUP ONE TRADING LLC added | 321,279 | $1M | 0.3% | 2025-Q4 stale |
| AMERICAN CENTURY COMPANIES INC added | 270,451 | $1M | 0.3% | 2025-Q4 stale |
| Numerai GP LLC new | 153,800 | $814K | 0.2% | 2025-Q3 stale |
| FRANKLIN RESOURCES INC | 356,357 | $780K | 0.2% | 2025-Q2 stale |
| TWO SIGMA ADVISERS, LP added | 176,200 | $721K | 0.2% | 2025-Q4 stale |
| VANGUARD GROUP INC trimmed | 153,583 | $628K | 0.2% | 2025-Q4 stale |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 151,453 | $619K | 0.2% | 2025-Q4 stale |
| PEAK6 LLC trimmed | 208,548 | $457K | 0.1% | 2025-Q2 stale |
| STEMPOINT CAPITAL LP new | 76,032 | $402K | 0.1% | 2025-Q3 stale |
| Z3 Capital Partners, LLC new | 94,950 | $388K | 0.1% | 2025-Q4 stale |
| Hyperion Capital Advisors LP | 168,416 | $369K | 0.1% | 2025-Q2 stale |
| TD Asset Management Inc added | 68,576 | $363K | 0.1% | 2025-Q3 stale |
| Connor, Clark & Lunn Investment Management Ltd. new | 84,244 | $345K | 0.1% | 2025-Q4 stale |
| DLD Asset Management, LP new | 60,000 | $317K | 0.1% | 2025-Q3 stale |
| SG Americas Securities, LLC added | 53,477 | $283K | 0.1% | 2025-Q3 stale |
| CAPTRUST FINANCIAL ADVISORS added | 50,000 | $264K | 0.1% | 2025-Q3 stale |
| FreeGulliver LLC new | 62,500 | $256K | 0.1% | 2025-Q4 stale |
| Sender Co & Partners, Inc. new | 43,176 | $228K | 0.1% | 2025-Q3 stale |
| SIMPLEX TRADING, LLC trimmed | 53,065 | $217K | 0.1% | 2025-Q4 stale |
| Diametric Capital, LP trimmed | 40,815 | $216K | 0.1% | 2025-Q3 stale |
| Virtu Financial LLC added | 95,746 | $210K | 0.1% | 2025-Q2 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.