Mark Cuban has an estimated net worth of $3.9 billion. He's earned his fortune through a lifetime of business deals, including the $5.7 billion sale of Broadcast.com, his ownership of the Dallas Mavericks, and investments made on ABC's "Shark Tank." Cuban has spent millions on private airplanes, a yacht, and a luxurious Dallas home, not to mention $2 million in fines from the NBA. Cuban is in the news this week after an investigation into the Mavericks organization surfaced evidence of a hostile workplace for women. Cuban has pledged to donate $10 million to women's causes and domestic violence awareness.