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 ($1.6m this quarter). Holder counts are more reliable. Shares outstanding: 134.4m as of 2026-07-30, 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 ≈ $46.60. Options: 17 managers hold calls ($175.7m notional), 14 hold puts ($71.4m).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q4 2025 | 8 |
| Q1 2026 | 245 |
| Q2 2026 | 360 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q1 2026 | 232 | 5 |
| Q2 2026 | 258 | 93 |
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 | $32.5m | $8.4m | 0.26 |
| Q2 2026 | $175.7m | $71.4m | 0.41 |
Biggest buyers
| Capital World Investors | New | +5.4m |
| PRICE T ROWE ASSOCIATES INC /MD/ | Added | +4.6m |
| Capital International Investors | New | +3.0m |
| FMR LLC | Added | +2.9m |
| BlackRock, Inc. | Added | +2.8m |
| Avoro Capital Advisors LLC | Added | +2.2m |
| ALLIANCEBERNSTEIN L.P. | Added | +1.7m |
| WELLINGTON MANAGEMENT GROUP LLP | Added | +1.6m |
| RA CAPITAL MANAGEMENT, L.P. | New | +1.5m |
| GEODE CAPITAL MANAGEMENT, LLC | Added | +1.1m |
Biggest sellers
| Trails Edge Capital Partners, LP | Sold out | -1.7m |
| ArrowMark Colorado Holdings LLC | Reduced | -1.0m |
| Candriam S.C.A. | Reduced | -679.2k |
| MILLENNIUM MANAGEMENT LLC | Reduced | -580.8k |
| STEMPOINT CAPITAL LP | Reduced | -513.8k |
| Catalio Capital Management, LP | Reduced | -475.3k |
| ORBIMED ADVISORS LLC | Reduced | -438.6k |
| Balyasny Asset Management L.P. | Reduced | -376.6k |
| Patient Square Capital LP | Sold out | -331.0k |
| Holocene Advisors, LP | Reduced | -295.4k |
Biggest calls
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $65.2m1.4m shares |
| JANE STREET GROUP, LLC | Added | $19.9m423.9k shares |
| Ally Bridge Group (NY) LLC | New | $18.8m400.0k shares |
| Caption Management, LLC | Added | $17.5m372.1k shares |
| SILVERBACK ASSET MANAGEMENT LLC | Unchanged | $13.8m294.4k shares |
| CITADEL ADVISORS LLC | Added | $13.5m288.0k shares |
| GROUP ONE TRADING LLC | Added | $12.5m265.7k shares |
| SIG BROKERAGE, LP | New | $4.4m93.2k shares |
| BARCLAYS PLC | New | $3.2m68.9k shares |
| SIMPLEX TRADING, LLC | Added | $1.8m39.0k shares |
Biggest puts
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $22.2m471.0k shares |
| JANE STREET GROUP, LLC | Added | $15.4m327.7k shares |
| CITADEL ADVISORS LLC | Added | $13.4m284.5k shares |
| MILLENNIUM MANAGEMENT LLC | New | $5.2m110.0k shares |
| SIMPLEX TRADING, LLC | Added | $4.8m102.7k shares |
| Fore Capital, LLC | New | $3.8m80.0k shares |
| Crawford Fund Management, LLC | Added | $2.6m55.7k shares |
| GROUP ONE TRADING LLC | Added | $2.5m52.5k shares |
| DLD Asset Management, LP | New | $709.7k15.1k shares |
| PEAK6 LLC | New | $423.4k9.0k 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 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.
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 |
|---|---|---|---|---|---|
| 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 |
| Q2 2026 | 0 | — | 5 | $2.6m | $2.6m |
| Q3 2026 | 0 | — | 5 | $3.0m | $3.0m |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-09-25 | Barrow Robert Chief Executive Officer, director | Sold plan | $1.2m31.6k shares |
| 2026-09-25 | Sullivan Mark Chief Legal Officer | Sold plan | $513.8k14.1k shares |
| 2026-09-25 | Karlin Daniel Chief Medical Officer, director | Sold plan | $396.9k10.9k shares |
| 2026-09-25 | Roberts Brandi Chief Financial Officer | Sold plan | $123.5k3.4k shares |
| 2026-09-25 | Wiley Matthew T. Chief Commercial Officer | Sold plan | $113.3k3.1k shares |
| 2026-09-03 | Barrow Robert Chief Executive Officer, director | Sold plan | $721.7k19.0k shares |
| 2026-06-25 | Barrow Robert Chief Executive Officer, director | Sold plan | $1.3m29.2k shares |
| 2026-06-25 | Sullivan Mark Chief Legal Officer | Sold plan | $585.8k13.0k shares |
| 2026-06-25 | Karlin Daniel Chief Medical Officer | Sold plan | $451.9k10.0k shares |
| 2026-06-25 | Roberts Brandi Chief Financial Officer | Sold plan | $135.7k3.0k shares |
| 2026-06-25 | Wiley Matthew T. Chief Commercial Officer | Sold plan | $129.1k2.9k 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, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| BlackRock, Inc. 0.01% of their portfolio | 11.2m $528.4m | Added +2.8m |
| Avoro Capital Advisors LLC 3.04% of their portfolio | 7.2m $338.2m | Added +2.2m |
| Driehaus Capital Management LLC 1.87% of their portfolio | 6.8m $322.0m | Added +933.4k |
| Jupiter Topco LLC 0.11% of their portfolio | 5.6m $264.0m | First filing |
| Capital World Investors 0.03% of their portfolio | 5.4m $252.5m | New |
| FMR LLC 0.01% of their portfolio | 4.8m $223.6m | Added +2.9m |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.02% of their portfolio | 4.7m $218.8m | Added +4.6m |
| GEODE CAPITAL MANAGEMENT, LLC 0.01% of their portfolio | 3.6m $171.5m | Added +1.1m |
| STATE STREET CORP 0.00% of their portfolio | 3.1m $144.2m | Added +593.5k |
| Capital International Investors 0.03% of their portfolio | 3.0m $139.4m | New |
| Octagon Capital Advisors LP 12.74% of their portfolio | 3.0m $138.8m | Added +510.0k |
| WELLINGTON MANAGEMENT GROUP LLP 0.02% of their portfolio | 2.9m $138.8m | Added +1.6m |
| Deep Track Capital, LP 1.91% of their portfolio | 2.8m $129.4m | Reduced -250.0k |
| Commodore Capital LP 5.60% of their portfolio | 2.0m $94.1m | Unchanged |
| ALLIANCEBERNSTEIN L.P. 0.01% of their portfolio | 1.8m $34.1m | Added +1.7m |
| GOLDMAN SACHS GROUP INC 0.01% of their portfolio | 1.8m $84.7m | Added +125.4k |
| CITADEL ADVISORS LLC 0.05% of their portfolio | 1.7m $79.4m | Added +355.1k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 1.6m $77.5m | Added +775.8k |
| RA CAPITAL MANAGEMENT, L.P. 0.61% of their portfolio | 1.5m $70.6m | New |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 1.5m $69.9m | Added +389.5k |
| Siren, L.L.C. 1.36% of their portfolio | 1.4m $66.8m | Added +500.0k |
| MARSHALL WACE, LLP 0.05% of their portfolio | 1.3m $61.1m | Added +98.1k |
| NORTHERN TRUST CORP 0.01% of their portfolio | 1.2m $55.0m | Added +370.3k |
| AMERIPRISE FINANCIAL INC 0.01% of their portfolio | 1.1m $54.0m | Added +181.8k |
| Nuveen, LLC 0.01% of their portfolio | 1.1m $52.0m | Added +407.2k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.01% of their portfolio | 1.1m $51.0m | Added +274.9k |
| Woodline Partners LP 0.15% of their portfolio | 1.0m $47.2m | Added +250.8k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.07% of their portfolio | 1.0m $47.0m | Reduced -150.0k |
| Boxer Capital Management, LLC 3.54% of their portfolio | 998.5k $47.0m | Added +400.0k |
| TWO SIGMA INVESTMENTS, LP 0.03% of their portfolio | 921.8k $43.4m | Reduced -279.8k |
| Balyasny Asset Management L.P. 0.08% of their portfolio | 897.7k $42.2m | Reduced -376.6k |
| VANGUARD FIDUCIARY TRUST CO 0.01% of their portfolio | 827.7k $38.9m | Added +251.8k |
| Holocene Advisors, LP 0.09% of their portfolio | 796.6k $37.5m | Reduced -295.4k |
| AWM Investment Company, Inc. 3.20% of their portfolio | 784.8k $36.9m | Reduced -292.1k |
| Bank of New York Mellon Corp 0.01% of their portfolio | 777.3k $36.6m | Added +24.3k |
| Polar Capital Holdings Plc 0.10% of their portfolio | 777.3k $36.6m | New |
| EVENTIDE ASSET MANAGEMENT, LLC 0.45% of their portfolio | 710.0k $33.4m | Added +23.8k |
| NEUBERGER BERMAN GROUP LLC 0.02% of their portfolio | 687.5k $32.3m | Added +554.2k |
| Qube Research & Technologies Ltd 0.04% of their portfolio | 682.9k $32.1m | Added +256.8k |
| Candriam S.C.A. 0.13% of their portfolio | 614.4k $28.9m | Reduced -679.2k |
| ArrowMark Colorado Holdings LLC 1.10% of their portfolio | 564.1k $26.5m | Reduced -1.0m |
| Catalio Capital Management, LP 4.97% of their portfolio | 562.7k $26.5m | Reduced -475.3k |
| Blackstone Inc. 0.09% of their portfolio | 561.6k $26.4m | Added +52.9k |
| Integral Health Asset Management, LLC 1.06% of their portfolio | 550.0k $25.9m | Added +150.0k |
| BAMCO INC /NY/ 0.04% of their portfolio | 520.1k $24.5m | New |
| UBS Group AG 0.00% of their portfolio | 499.5k $23.5m | Added +5.5k |
| FRANKLIN RESOURCES INC 0.00% of their portfolio | 486.2k $22.9m | New |
| Point72 Asset Management, L.P. 0.03% of their portfolio | 484.0k $22.8m | Added +308.5k |
| Ensign Peak Advisors, Inc 0.04% of their portfolio | 466.1k $21.9m | Reduced -80.7k |
| MORGAN STANLEY 0.00% of their portfolio | 454.9k $21.4m | Added +16.3k |
| GREAT POINT PARTNERS LLC 4.71% of their portfolio | 425.0k $20.0m | New |
| RTW INVESTMENTS, LP 0.16% of their portfolio | 400.0k $18.8m | Added +100.0k |
| Cormorant Asset Management, LP 0.96% of their portfolio | 400.0k $18.8m | New |
| SILVERARC CAPITAL MANAGEMENT, LLC 2.09% of their portfolio | 400.0k $18.8m | New |
| ASSETMARK, INC 0.03% of their portfolio | 396.5k $18.7m | New |
| ORBIMED ADVISORS LLC 0.33% of their portfolio | 365.4k $17.2m | Reduced -438.6k |
| Duquesne Family Office LLC 0.39% of their portfolio | 356.6k $16.8m | New |
| D. E. Shaw & Co., Inc. 0.01% of their portfolio | 315.4k $14.8m | Added +43.7k |
| Tetragon Partners GP Ltd 2.20% of their portfolio | 287.0k $13.5m | Added +87.0k |
| MILLENNIUM MANAGEMENT LLC 0.01% of their portfolio | 266.1k $12.5m | Reduced -580.8k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 266.0k $12.4m | Added +1.4k |
| Sofinnova Investments, Inc. 0.64% of their portfolio | 255.9k $12.0m | Reduced -88.3k |
| PFM Health Sciences, LP 1.02% of their portfolio | 249.0k $11.7m | Added +43.7k |
| HighVista Strategies LLC 2.60% of their portfolio | 242.9k $11.4m | Added +57.0k |
| Trexquant Investment LP 0.07% of their portfolio | 233.2k $11.0m | New |
| SEVEN GRAND MANAGERS, LLC 0.43% of their portfolio | 225.0k $10.6m | Unchanged |
| Swiss National Bank 0.01% of their portfolio | 221.2k $10.4m | Added +62.8k |
| Eversept Partners, LP 0.56% of their portfolio | 217.2k $10.2m | Added +56.5k |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio | 211.2k $9.9m | Added +208.8k |
| TD Asset Management Inc 0.01% of their portfolio | 209.5k $9.9m | New |
| ROYCE & ASSOCIATES LP 0.08% of their portfolio | 208.6k $9.8m | Reduced -25.5k |
| SEB Asset Management AB 0.04% of their portfolio | 208.3k $9.8m | New |
| SUPERSTRING CAPITAL MANAGEMENT LP 5.59% of their portfolio | 188.3k $8.9m | Reduced -163.2k |
| EMERALD ADVISERS, LLC 0.20% of their portfolio | 178.8k $8.4m | New |
| Aberdeen Group plc 0.01% of their portfolio | 175.0k $8.2m | New |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 164.6k $7.7m | Added +6.2k |
| Tri Locum Partners LP 0.94% of their portfolio | 163.0k $7.7m | Reduced -206.6k |
| RHUMBLINE ADVISERS 0.01% of their portfolio | 158.1k $7.4m | Added +38.1k |
| Brevan Howard Capital Management LP 0.10% of their portfolio | 156.8k $7.4m | Reduced -54.7k |
| Russell Investments Group, Ltd. 0.01% of their portfolio | 153.5k $7.2m | Added +34.0k |
| LMR Partners LLP 0.05% of their portfolio | 150.2k $7.1m | New |
| Seven Fleet Capital Management LP 1.15% of their portfolio | 148.6k $7.0m | Added +48.8k |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.01% of their portfolio | 146.4k $6.9m | Added +120.0k |
| Rock Springs Capital Management LP 0.33% of their portfolio | 143.2k $6.7m | New |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 142.9k $6.7m | Reduced -268.9k |
| SummitTX Capital, L.P. 0.18% of their portfolio | 142.5k $6.7m | New |
| STEMPOINT CAPITAL LP 1.12% of their portfolio | 137.1k $6.5m | Reduced -513.8k |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 134.2k $6.3m | Added +77.1k |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.01% of their portfolio | 128.3k $6.0m | New |
| BIT Capital GmbH 0.21% of their portfolio | 128.1k $6.0m | Reduced -149.4k |
| FRED ALGER MANAGEMENT, LLC 0.02% of their portfolio | 125.3k $5.9m | Added +33.1k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 122.0k $5.7m | Added +82.1k |
| Atika Capital Management LLC 0.57% of their portfolio | 122.0k $5.7m | New |
| AdvisorShares Investments LLC 0.69% of their portfolio | 121.4k $5.7m | Added +30.1k |
| EMERALD MUTUAL FUND ADVISERS TRUST 0.20% of their portfolio | 121.2k $5.7m | New |
| Informed Momentum Co LLC 0.51% of their portfolio | 120.9k $5.7m | New |
| Schonfeld Strategic Advisors LLC 0.03% of their portfolio | 119.6k $5.6m | Added +109.2k |
| HSBC HOLDINGS PLC 0.00% of their portfolio | 117.5k $5.5m | New |
| ALPS ADVISORS INC 0.02% of their portfolio | 110.4k $5.2m | New |
| Data Collective IV GP, LLC 6.01% of their portfolio | 100.3k $4.7m | Unchanged |