Mark Sullivan - Net Worth and Insider Trading
Mark Sullivan Net Worth
The estimated net worth of Mark Sullivan is at least $12 Million dollars as of 2026-09-11. Mark Sullivan is the Chief Legal Officer of Definium Therapeutics Inc and owns about 320,571 shares of Definium Therapeutics Inc (DFTX) stock worth over $12 Million. Mark Sullivan is also the General Counsel & Secretary of Sesen Bio Inc and owns about 18,933 shares of Sesen Bio Inc (SESN) stock worth over $11,905. Details can be seen in Mark Sullivan's Latest Holdings Summary section.
Disclaimer: The insider information is derived from SEC filings. The estimated net worth is based on the final shares held after open market or private purchases and sales of common stock with a transaction code of "P" or "S" on Form 4, assuming that Mark Sullivan has not made any transactions after 2026-06-25 and currently still holds the listed stock(s). Please note that this estimate may not reflect the actual net worth.
Transaction Summary of Mark Sullivan
Mark Sullivan Insider Ownership Reports
Based on ownership reports from SEC filings, as the reporting owner, Mark Sullivan owns 3 companies in total, including Sesen Bio Inc (SESN) , CARISMA Therapeutics Inc (CARM) , and Definium Therapeutics Inc (DFTX) .
Click here to see the complete history of Mark Sullivan’s form 4 insider trades.
Insider Ownership Summary of Mark Sullivan
| Ticker | Company | Transaction Date | Type of Owner |
|---|---|---|---|
| SESN | Sesen Bio Inc | 2023-03-02 | General Counsel & Secretary |
| CARM | CARISMA Therapeutics Inc | 2019-08-01 | General Counsel & Secretary |
| DFTX | Definium Therapeutics Inc | 2026-06-25 | Chief Legal Officer |
Mark Sullivan Latest Holdings Summary
Mark Sullivan currently owns a total of 2 stocks. Among these stocks, Mark Sullivan owns 320,571 shares of Definium Therapeutics Inc (DFTX) as of June 25, 2026, with a value of $12 Million and a weighting of 99.9%. Mark Sullivan also owns 18,933 shares of Sesen Bio Inc (SESN) as of March 2, 2023, with a value of $11,905 and a weighting of 0.1%.
Latest Holdings of Mark Sullivan
| Ticker | Company | Latest Transaction Date | Shares Owned | Current Price ($) | Current Value ($) |
|---|---|---|---|---|---|
| DFTX | Definium Therapeutics Inc | 2026-06-25 | 320,571 | 38.89 | 12,467,006 |
| SESN | Sesen Bio Inc | 2023-03-02 | 18,933 | 0.63 | 11,905 |
Holding Weightings of Mark Sullivan
Mark Sullivan Form 4 Trading Tracker
According to the SEC Form 4 filings, Mark Sullivan has made a total of 8 transactions in Definium Therapeutics Inc (DFTX) over the past 5 years, including 0 buys and 8 sells. The most-recent trade in Definium Therapeutics Inc is the sale of 13,008 shares on June 25, 2026, which brought Mark Sullivan around $585,750.
According to the SEC Form 4 filings, Mark Sullivan has made a total of 2 transactions in Sesen Bio Inc (SESN) over the past 5 years, including 0 buys and 2 sells. The most-recent trade in Sesen Bio Inc is the sale of 10,961 shares on March 2, 2023, which brought Mark Sullivan around $129,339.
Insider Trading History of Mark Sullivan
* The information on this page (including Insider Trading Shares, Share Changes, Cost, etc.) is sourced exclusively from Form 4 filings and does not incorporate any data from 13F or 13D/G filings. As a result, it may differ from the values shown on the Guru page.
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Mark Sullivan Trading Performance
Mark Sullivan Ownership Network
Ownership Network List of Mark Sullivan
Ownership Network Relation of Mark Sullivan
Mark Sullivan Owned Company Details
What does Sesen Bio Inc do?
Who are the key executives at Sesen Bio Inc?
Mark Sullivan is the General Counsel & Secretary of Sesen Bio Inc. Other key executives at Sesen Bio Inc include 10 percent owner Modernatx, Inc. , Chief Scientific Officer Michael Klichinsky , and director & President and CEO Steven Kelly .
Sesen Bio Inc (SESN) Insider Trades Summary
In summary, during the past 3 months, insiders sold 0 shares of Sesen Bio Inc (SESN) in total and bought 0 shares, with a net sale of 0 shares. During the past 18 months, 0 shares of Sesen Bio Inc (SESN) were sold and 0 shares were bought by its insiders, resulting in a net sale of 0 shares.
Sesen Bio Inc (SESN)'s detailed insider trading history can be found in Insider Trading Tracker table.
Sesen Bio Inc Insider Transactions
Mark Sullivan Mailing Address
Above is the net worth, insider trading, and ownership report for Mark Sullivan. Based on the public information released on the U.S. Securities and Exchange Commission (SEC) website, Mark Sullivan's mailing address is: Mount Laurel Nj 08054.
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