12-year-old Mark Cuban started his first business so he could buy new basketball shoes. Now he’s one of the most successful people alive. Mark Cuban made his first billion when he sold Broadcast.com to Yahoo in 1999, and he’s been raking in profits ever since. A colorful personality and leading investor on ABC’s hit television series “Shark Tank,” he prides himself on helping entrepreneurs and business owners succeed. Most recently, Mark has taken the Dallas Mavericks from a local NBA franchise to a billion-dollar business.