Mark Cuban is a lot of things. He's a billionaire internet entrepreneur, owner of the Dallas Mavericks, chairman of HDNet, and a Dancing With the Stars loser. And now the Securities and Exchange Commission would like to add one more descriptor for the outspoken investor: insider trader.

The S.E.C. charged Cuban with trading shares of Mamma.com, now known as Copernic, based on insider information. Cuban invested in the fledgling internet search engine in early 2004. In June of that year, the S.E.C. alleges, Mamma.com invited Cuban to participate in a stock offering after he agreed to keep the information confidential. He allegedly knew the offering would be at a price lower than the market price and would be dilutive to shareholders.

Cuban allegedly instructed his broker to sell his stake just hours after receiving the information. Based on the stock's decline after the offering was made public, Cuban avoided $750,000 in losses by selling early.

Interestingly, Cuban blogged about this trade on Blogmaverick.com.

"It's not Google or Yahoo, nor will it be a top 5 search engine anytime soon. But it is a good metasearch tool that I use and have used. Google and Yahoo have become carbon copies of each other, and for me, other than usenet and news searches, it's too big. I like the way Mamma.com organizes web searches, and I use it for picture searches."

"Then the company did a P.I.P.E. financing. I'm not going to discuss the good or bad of P.I.P.E. financing [private investment in a public entity] other than to say that to me it's a huge red flag and I don't want to own stock in companies that use this method of financing. Why? Because I don't like the idea of selling in a private placement, stock for less than the market price, and then to make matters worse, pushing the price lower with the issuance of warrants. So I sold the stock…I'm glad I sold my stock."

UPDATE: Mark Cuban responds. “I am disappointed that the Commission chose to bring this case based upon its Enforcement staff’s win-at-any-cost ambitions. The staff’s process was result-oriented, facts be damned. The government’s claims are false and they will be proven to be so.”