Mark D Klein - Net Worth and Insider Trading
Mark D Klein Net Worth
The estimated net worth of Mark D Klein is at least $22 Million dollars as of 2026-09-10. Mark D Klein is the Chairman, CEO and President of Neostellar Capital Corp and owns about 1,758,796 shares of Neostellar Capital Corp (NSLR) stock worth over $17 Million. Mark D Klein is also the Director of Churchill Capital Corp III and owns about 481,711 shares of Churchill Capital Corp III (CCXX) stock worth over $5 Million. Details can be seen in Mark D Klein'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 D Klein has not made any transactions after 2026-08-10 and currently still holds the listed stock(s). Please note that this estimate may not reflect the actual net worth.
Transaction Summary of Mark D Klein
Mark D Klein Insider Ownership Reports
Based on ownership reports from SEC filings, as the reporting owner, Mark D Klein owns 20 companies in total, including Churchill Capital Corp III (CCXX.U) , Churchill Capital Corp IV (CCIV.U) , and Neostellar Capital Corp (NSLR) among others .
Click here to see the complete history of Mark D Klein’s form 4 insider trades.
Insider Ownership Summary of Mark D Klein
| Ticker | Company | Transaction Date | Type of Owner |
|---|---|---|---|
| CCXX.U | Churchill Capital Corp III | 2020-10-06 | director |
| CCIV.U | Churchill Capital Corp IV | 2020-07-29 | director |
| NSLR | Neostellar Capital Corp | 2026-08-10 | director & CEO and President |
| 2019-06-26 | director | ||
| 2015-11-30 | other: See Footnote 1 | ||
| 2010-08-02 | director | ||
| 2010-05-19 | director & Chief Executive Officer | ||
| 2009-01-12 | director | ||
| 2008-01-17 | 10 percent owner | ||
| 2005-04-01 | director & President and CEO | ||
| 2005-04-01 | director & President and CEO | ||
| 2019-06-26 | director | ||
| 2020-02-19 | director | ||
| 2020-07-29 | director | ||
| 2020-12-15 | director | ||
| 2021-02-11 | director | ||
| 2021-02-11 | director | ||
| 2020-12-15 | director | ||
| 2021-02-11 | director | ||
| 2021-02-11 | director |
Mark D Klein Latest Holdings Summary
Mark D Klein currently owns a total of 2 stocks. Among these stocks, Mark D Klein owns 1,758,796 shares of Neostellar Capital Corp (NSLR) as of August 10, 2026, with a value of $17 Million and a weighting of 78.33%. Mark D Klein also owns 481,711 shares of Churchill Capital Corp III (CCXX) as of October 7, 2020, with a value of $5 Million and a weighting of 21.67%.
Latest Holdings of Mark D Klein
| Ticker | Company | Latest Transaction Date | Shares Owned | Current Price ($) | Current Value ($) |
|---|---|---|---|---|---|
| NSLR | Neostellar Capital Corp | 2026-08-10 | 1,758,796 | 9.74 | 17,130,673 |
| CCXX | Churchill Capital Corp III | 2020-10-07 | 481,711 | 9.84 | 4,740,036 |
Holding Weightings of Mark D Klein
Mark D Klein Form 4 Trading Tracker
According to the SEC Form 4 filings, Mark D Klein has made a total of 15 transactions in Neostellar Capital Corp (NSLR) over the past 5 years, including 15 buys and 0 sells. The most-recent trade in Neostellar Capital Corp is the acquisition of 26,040 shares on August 10, 2026, which cost Mark D Klein around $249,984.
According to the SEC Form 4 filings, Mark D Klein has made a total of 0 transactions in Churchill Capital Corp III (CCXX) over the past 5 years. The most-recent trade in Churchill Capital Corp III is the acquisition of 481,711 shares on October 7, 2020, which cost Mark D Klein around $5 Million.
Insider Trading History of Mark D Klein
* 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 D Klein Trading Performance
GuruFocus tracks the stock performance after each of Mark D Klein's buying transactions within different timeframes. To be detailed, the average return of stocks after 3 months bought by Mark D Klein is 10.22%. GuruFocus also compares Mark D Klein's trading performance to market benchmark return within the same time period. The performance of stocks bought by Mark D Klein within 3 months outperforms 21 times out of 47 transactions in total compared to the return of S&P 500 within the same period.
You can select different timeframes to see how Mark D Klein's insider trading performs compared to the benchmark.
Performance of Mark D Klein
Mark D Klein Ownership Network
Ownership Network List of Mark D Klein
Ownership Network Relation of Mark D Klein

Mark D Klein Owned Company Details
What does Churchill Capital Corp III do?
Who are the key executives at Churchill Capital Corp III?
Mark D Klein is the director of Churchill Capital Corp III. Other key executives at Churchill Capital Corp III include President & New Markets Paul Galant , See Remarks Michael Kim , and 10 percent owner H&f Polaris Partners Gp, Llc .
Churchill Capital Corp III (CCXX.U) Insider Trades Summary
In summary, during the past 3 months, insiders sold 0 shares of Churchill Capital Corp III (CCXX.U) in total and bought 0 shares, with a net sale of 0 shares. During the past 18 months, 0 shares of Churchill Capital Corp III (CCXX.U) were sold and 0 shares were bought by its insiders, resulting in a net sale of 0 shares.
Churchill Capital Corp III (CCXX.U)'s detailed insider trading history can be found in Insider Trading Tracker table.
Churchill Capital Corp III Insider Transactions
Mark D Klein Mailing Address
Above is the net worth, insider trading, and ownership report for Mark D Klein. Based on the public information released on the U.S. Securities and Exchange Commission (SEC) website, Mark D Klein's mailing address is: Woodland Hills Ca 91367.