Definium Therapeutics, Inc.
Ownership
Ownership Structure
Who owns Definium Therapeutics, Inc. (DFTX)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 93.4% of the shares are freely tradable; institutional investors hold 65.6%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 8.36 | 11,232,834 | +32.5 | 06/30/2026 |
| venBio Select Advisor LLC | 5.35 | 7,188,888 | +43.8 | 06/30/2026 |
| Driehaus Capital Management LLC | 5.09 | 6,845,276 | +15.8 | 06/30/2026 |
| Jupiter Topco LLC | 4.18 | 5,615,645 | +0.0 | 06/30/2026 |
| Capital World Investors | 3.99 | 5,367,723 | +0.0 | 06/30/2026 |
| FMR Inc | 3.54 | 4,752,921 | +162.6 | 06/30/2026 |
| T. Rowe Price Associates, Inc. | 3.46 | 4,652,032 | +6,545.7 | 06/30/2026 |
| Geode Capital Management, LLC | 2.71 | 3,644,813 | +46.1 | 06/30/2026 |
| HHG PLC | 2.65 | 3,556,041 | +47.4 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| American Funds SMALLCAP World A | 7.63 | 10,253,153 | +33.3 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Barrow Robert | Chief Executive Officer | 2,213,090 | 73,917,206 $ | Sep 25, 2026 | direct |
| Karlin Daniel | Chief Medical Officer | 792,846 | 26,481,056 $ | Sep 25, 2026 | direct |
| Sullivan Mark | Chief Legal Officer | 494,228 | 16,507,215 $ | Sep 25, 2026 | direct |
| Roberts Brandi | Chief Financial Officer | 394,528 | 13,177,235 $ | Sep 25, 2026 | direct |
| Wiley Matthew T. | Chief Commercial Officer | 359,036 | 11,991,802 $ | Sep 25, 2026 | direct |
| Vallone Carol A | Director | 22,296 | 744,686 $ | Sep 18, 2026 | direct |
| Krebs Andreas | Director | 21,402 | 714,827 $ | Sep 18, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Sep 25, 2026 | Karlin Daniel | Chief Medical Officer | Sell | 10,853 | 36.57 | 396,894 |
| Sep 25, 2026 | Barrow Robert | Chief Executive Officer | Sell | 31,550 | 36.57 | 1,153,784 |
| Sep 25, 2026 | Wiley Matthew T. | Chief Commercial Officer | Sell | 3,097 | 36.57 | 113,257 |
| Sep 25, 2026 | Sullivan Mark | Chief Legal Officer | Sell | 14,051 | 36.57 | 513,845 |
| Sep 25, 2026 | Roberts Brandi | Chief Financial Officer | Sell | 3,377 | 36.57 | 123,497 |
| Sep 18, 2026 | Krebs Andreas | Director | Other | 1,629 | 35.52 | 57,862 |
| Sep 18, 2026 | Vallone Carol A | Director | Other | 1,086 | 35.52 | 38,575 |
| Sep 14, 2026 | Karlin Daniel | Chief Medical Officer | Other | 200,000 | 0.00 | – |
| Sep 14, 2026 | Wiley Matthew T. | Chief Commercial Officer | Other | 125,000 | 0.00 | – |
| Sep 14, 2026 | Sullivan Mark | Chief Legal Officer | Other | 125,000 | 0.00 | – |
| Sep 14, 2026 | Roberts Brandi | Chief Financial Officer | Other | 125,000 | 0.00 | – |
| Sep 14, 2026 | Barrow Robert | Chief Executive Officer | Other | 750,000 | 0.00 | – |
| Sep 3, 2026 | Barrow Robert | Chief Executive Officer | Sell | 19,023 | 37.94 | 721,733 |
| Sep 2, 2026 | Barrow Robert | Chief Executive Officer | Other | 40,000 | 0.00 | – |
| Aug 12, 2026 | Barrow Robert | Chief Executive Officer | Other | 375,000 | 0.00 | – |
| Aug 12, 2026 | Karlin Daniel | Chief Medical Officer | Other | 100,000 | 0.00 | – |
| Aug 12, 2026 | Sullivan Mark | Chief Legal Officer | Other | 62,500 | 0.00 | – |
| Aug 12, 2026 | Wiley Matthew T. | Chief Commercial Officer | Other | 62,500 | 0.00 | – |
| Aug 12, 2026 | Roberts Brandi | Chief Financial Officer | Other | 62,500 | 0.00 | – |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: November 3, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.