DEFINIUM THERAPEUTICS INC DFTX
COM SHS · Common Stock · CUSIP 24477V105
American clinical-stage biopharmaceutical company developing psychedelic-based treatments
- SectorHealth care
- IndustryMedicinal Chemicals & Botanical Products
- HeadquartersNew York, NY
- Websitedefiniumtx.com
- 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 ($148.2k this quarter). Holder counts are more reliable. Shares outstanding: 109.1m as of 2026-04-30, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $18.89. Options: 11 managers hold calls ($32.5m notional), 7 hold puts ($8.4m).
Trends to Q1 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q4 2025 | 8 |
| Q1 2026 | 245 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q2 2025 | $0 | $0 | — |
| Q3 2025 | $0 | $0 | — |
| Q4 2025 | $0 | $0 | — |
| Q1 2026 | $32.5m | $8.4m | 0.26 |
Biggest buyers
| BlackRock, Inc. | New | +8.5m |
| Avoro Capital Advisors LLC | New | +5.0m |
| JANUS HENDERSON GROUP PLC | New | +3.6m |
| Deep Track Capital, LP | New | +3.0m |
| GEODE CAPITAL MANAGEMENT, LLC | New | +2.5m |
| STATE STREET CORP | New | +2.5m |
| Octagon Capital Advisors LP | New | +2.4m |
| Commodore Capital LP | New | +2.0m |
| FMR LLC | New | +1.8m |
| Trails Edge Capital Partners, LP | New | +1.7m |
Biggest sellers
| MARSHALL WACE, LLP | Reduced | -1.8m |
| Driehaus Capital Management LLC | Reduced | -625.3k |
| AWM Investment Company, Inc. | Reduced | -313.8k |
| DARK FOREST CAPITAL MANAGEMENT LP | Sold out | -30.7k |
| Sankala Group LLC | Reduced | -250 |
Biggest calls
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | New | $15.9m840.0k shares |
| SILVERBACK ASSET MANAGEMENT LLC | New | $5.6m294.4k shares |
| Caption Management, LLC | New | $4.0m212.1k shares |
| GROUP ONE TRADING LLC | New | $3.3m172.0k shares |
| CITADEL ADVISORS LLC | New | $1.6m85.7k shares |
| JANE STREET GROUP, LLC | New | $996.0k52.7k shares |
| PEAK6 LLC | New | $567.0k30.0k shares |
| SIMPLEX TRADING, LLC | New | $258.9k13.7k shares |
| Shay Capital LLC | New | $189.0k10.0k shares |
| Walleye Trading LLC | New | $104.0k5.5k shares |
Biggest puts
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | New | $4.1m216.2k shares |
| CITADEL ADVISORS LLC | New | $1.3m70.1k shares |
| SIMPLEX TRADING, LLC | New | $1.3m69.1k shares |
| JANE STREET GROUP, LLC | New | $652.0k34.5k shares |
| GROUP ONE TRADING LLC | New | $618.0k32.7k shares |
| Crawford Fund Management, LLC | New | $400.7k21.2k shares |
| Walleye Trading LLC | New | $58.6k3.1k 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 |
|---|---|
| DRIEHAUS CAPITAL MANAGEMENT LLC 13G · institution -1.3 pts · filed 2026-08-14 | 5.4% |
| Avoro Capital Advisors LLC 13G · institution new · filed 2026-02-17 | 5.1% |
Fell to 5% or below in the last year: Commodore Capital LP (1.8%, 2026-08-14), Deep Track Capital, LP (3.0%, 2026-05-15)
Insider purchases and sales in Q1 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.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q2 2024 | 0 | — | 3 | $292.0k | $292.0k |
| Q3 2024 | 2 | $27.1k | 4 | $199.9k | $199.9k |
| Q4 2024 | 1 | $17.9k | 4 | $241.8k | $241.8k |
| Q1 2025 | 0 | — | 4 | $249.2k | $249.2k |
| Q2 2025 | 0 | — | 3 | $311.6k | $311.6k |
| Q3 2025 | 0 | — | 3 | $437.5k | $437.5k |
| Q4 2025 | 0 | — | 3 | $561.1k | $561.1k |
| Q1 2026 | 0 | — | 3 | $797.0k | $797.0k |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-03-25 | Barrow Robert Chief Executive Officer, director | Sold plan | $451.2k24.4k shares |
| 2026-03-25 | Sullivan Mark Chief Legal Officer | Sold plan | $197.7k10.7k shares |
| 2026-03-25 | Karlin Daniel Chief Medical Officer | Sold plan | $148.1k8.0k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q1 2026
| Manager | Shares | Change |
|---|---|---|
| BlackRock, Inc. 0.00% of their portfolio | 8.5m $160.3m | New |
| Driehaus Capital Management LLC 0.82% of their portfolio | 5.9m $111.7m | Reduced -625.3k |
| Avoro Capital Advisors LLC 0.93% of their portfolio | 5.0m $94.5m | New |
| JANUS HENDERSON GROUP PLC 0.03% of their portfolio | 3.6m $67.2m | New |
| Deep Track Capital, LP 1.17% of their portfolio | 3.0m $56.7m | New |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 2.5m $47.2m | New |
| STATE STREET CORP 0.00% of their portfolio | 2.5m $46.7m | New |
| Octagon Capital Advisors LP 5.10% of their portfolio | 2.4m $46.1m | New |
| Commodore Capital LP 2.19% of their portfolio | 2.0m $37.8m | New |
| FMR LLC 0.00% of their portfolio | 1.8m $34.2m | New |
| Trails Edge Capital Partners, LP 7.73% of their portfolio | 1.7m $32.9m | New |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 1.7m $31.7m | New |
| ArrowMark Colorado Holdings LLC 0.80% of their portfolio | 1.6m $30.1m | New |
| CITADEL ADVISORS LLC 0.02% of their portfolio | 1.3m $25.2m | New |
| WELLINGTON MANAGEMENT GROUP LLP 0.00% of their portfolio | 1.3m $24.7m | New |
| Candriam S.C.A. 0.13% of their portfolio | 1.3m $24.4m | New |
| Balyasny Asset Management L.P. 0.05% of their portfolio | 1.3m $24.1m | New |
| TWO SIGMA INVESTMENTS, LP 0.02% of their portfolio | 1.2m $22.7m | New |
| MARSHALL WACE, LLP 0.02% of their portfolio | 1.2m $22.7m | Reduced -1.8m |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.03% of their portfolio | 1.1m $21.7m | New |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 1.1m $20.7m | First filing |
| Holocene Advisors, LP 0.05% of their portfolio | 1.1m $20.6m | New |
| AWM Investment Company, Inc. 2.25% of their portfolio | 1.1m $20.4m | Reduced -313.8k |
| Catalio Capital Management, LP 4.10% of their portfolio | 1.0m $19.6m | New |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 966.6k $18.3m | New |
| Siren, L.L.C. 0.48% of their portfolio | 919.5k $17.4m | New |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 872.7k $16.5m | First filing |
| MILLENNIUM MANAGEMENT LLC 0.01% of their portfolio | 846.9k $16.0m | New |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 808.7k $15.3m | New |
| ORBIMED ADVISORS LLC 0.33% of their portfolio | 804.0k $15.2m | New |
| NORTHERN TRUST CORP 0.00% of their portfolio | 799.0k $15.1m | New |
| Bank of New York Mellon Corp 0.00% of their portfolio | 752.9k $14.2m | New |
| Woodline Partners LP 0.05% of their portfolio | 752.8k $14.2m | New |
| Nuveen, LLC 0.00% of their portfolio | 698.1k $13.2m | New |
| EVENTIDE ASSET MANAGEMENT, LLC 0.21% of their portfolio | 686.2k $13.0m | New |
| STEMPOINT CAPITAL LP 1.19% of their portfolio | 651.0k $12.3m | New |
| Boxer Capital Management, LLC 1.49% of their portfolio | 598.5k $11.3m | New |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 575.9k $10.9m | First filing |
| Ensign Peak Advisors, Inc 0.02% of their portfolio | 546.8k $10.3m | Added +284.8k |
| Blackstone Inc. 0.04% of their portfolio | 508.7k $9.6m | Not comparable |
| UBS Group AG 0.00% of their portfolio | 494.0k $9.3m | New |
| MORGAN STANLEY 0.00% of their portfolio | 438.6k $8.3m | New |
| Qube Research & Technologies Ltd 0.01% of their portfolio | 426.1k $8.1m | New |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 411.8k $7.8m | New |
| Integral Health Asset Management, LLC 0.40% of their portfolio | 400.0k $7.6m | New |
| Tri Locum Partners LP 0.98% of their portfolio | 369.6k $7.0m | New |
| SUPERSTRING CAPITAL MANAGEMENT LP 4.75% of their portfolio | 351.5k $6.6m | New |
| Sofinnova Investments, Inc. 0.33% of their portfolio | 344.2k $6.5m | New |
| Patient Square Capital LP 1.11% of their portfolio | 331.0k $6.3m | New |
| RTW INVESTMENTS, LP 0.06% of their portfolio | 300.0k $5.7m | New |
| BIT Capital GmbH 0.29% of their portfolio | 277.5k $5.2m | New |
| D. E. Shaw & Co., Inc. 0.00% of their portfolio | 271.7k $5.1m | New |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 264.5k $4.6m | New |
| JANE STREET GROUP, LLC 0.01% of their portfolio | 260.2k $4.9m | New |
| ROYCE & ASSOCIATES LP 0.04% of their portfolio | 234.1k $4.4m | New |
| SEVEN GRAND MANAGERS, LLC 0.28% of their portfolio | 225.0k $4.3m | New |
| Brevan Howard Capital Management LP 0.04% of their portfolio | 211.5k $4.0m | New |
| PFM Health Sciences, LP 0.41% of their portfolio | 205.3k $3.9m | New |
| Tetragon Partners GP Ltd 0.74% of their portfolio | 200.0k $3.8m | New |
| HighVista Strategies LLC 0.97% of their portfolio | 185.9k $3.5m | New |
| Point72 Asset Management, L.P. 0.01% of their portfolio | 175.5k $3.3m | New |
| Eversept Partners, LP 0.20% of their portfolio | 160.7k $3.0m | New |
| Swiss National Bank 0.00% of their portfolio | 158.4k $3.0m | New |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 158.3k $3.0m | New |
| Soviero Asset Management, LP 1.49% of their portfolio | 140.0k $2.6m | New |
| NEUBERGER BERMAN GROUP LLC 0.00% of their portfolio | 133.4k $2.5m | New |
| Squarepoint Ops LLC 0.01% of their portfolio | 125.5k $2.4m | New |
| Rosalind Advisors, Inc. 0.97% of their portfolio | 125.0k $2.4m | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 120.0k $2.3m | New |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 119.5k $2.3m | New |
| ExodusPoint Capital Management, LP 0.02% of their portfolio | 104.9k $2.0m | New |
| Data Collective IV GP, LLC 3.39% of their portfolio | 100.3k $1.9m | New |
| Burkehill Global Management, LP 0.09% of their portfolio | 100.0k $1.9m | New |
| Seven Fleet Capital Management LP 0.59% of their portfolio | 99.9k $1.9m | New |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 97.2k $1.8m | New |
| FRED ALGER MANAGEMENT, LLC 0.01% of their portfolio | 92.2k $1.7m | New |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 91.7k $1.7m | New |
| AdvisorShares Investments LLC 0.31% of their portfolio | 91.3k $1.7m | New |
| HRT FINANCIAL LP 0.01% of their portfolio | 89.1k $1.7m | New |
| Invesco Ltd. 0.00% of their portfolio | 88.1k $1.7m | New |
| GROUP ONE TRADING LLC 0.05% of their portfolio | 87.8k $1.7m | New |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio | 81.5k $1.5m | New |
| LPL Financial LLC 0.00% of their portfolio | 78.3k $1.5m | New |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 70.0k $1.3m | Added +17.8k |
| PLATINUM INVESTMENT MANAGEMENT LTD 0.33% of their portfolio | 70.0k $1.3m | New |
| Rathbones Group PLC 0.00% of their portfolio | 60.4k $1.1m | New |
| Legal & General Group Plc 0.00% of their portfolio | 59.8k $1.1m | New |
| Ikarian Capital, LLC 0.16% of their portfolio | 58.8k $1.1m | New |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 57.1k $1.1m | New |
| Rockefeller Capital Management L.P. 0.00% of their portfolio | 55.2k $1.0m | New |
| MetLife Investment Management, LLC 0.01% of their portfolio | 54.3k $1.0m | New |
| VANGUARD ASSET MANAGEMENT, Ltd 0.00% of their portfolio | 54.0k $1.0m | First filing |
| BLAIR WILLIAM & CO/IL 0.00% of their portfolio | 53.7k $1.0m | New |
| KESTRA PRIVATE WEALTH SERVICES, LLC 0.01% of their portfolio | 50.6k $956.1k | New |
| STATE OF WISCONSIN INVESTMENT BOARD 0.00% of their portfolio | 50.4k $952.9k | New |
| NISA INVESTMENT ADVISORS, LLC 0.00% of their portfolio | 48.9k $924.3k | New |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 48.0k $908.0k | First filing |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 46.2k $873.0k | New |
| ALLSTATE CORP 0.01% of their portfolio | 45.4k $857.4k | New |
| CenterBook Partners LP 0.04% of their portfolio | 42.8k $809.5k | New |