He's famous for appearing on "Shark Tank" and for being the owner of the Dallas Mavericks, but Monday, Mark Cuban is expected to testify in his federal trial on charges he benefited from insider trading.
The billionaire is accused of using insider information to dump his stock in a small Internet-search company in 2004 just before the shares fell in value. He avoided $750,000 in losses. The Securities and Exchange Commission wants Cuban to give up the money and pay a civil penalty.
The SEC's key evidence is a phone call between Cuban and the CEO of Mamma.com.
According to the SEC, the CEO told Cuban he had confidential information to share and Cuban agreed to keep it to himself.
Cuban disputes the SEC's claims, and his lawyers argue that insider-trading laws didn't prohibit him from selling his shares.