Nike, Reebok, Adidas, and Puma, in 2012. The Taiwanese company, with revenues of more than $8 billion, was founded by the Wharton grad's father almost 50 years ago and now claims to be the world's largest manufacturer of athletic and casual footwear. Its operations are sprawling, with more than 400,000 employees in Mexico, Indonesia, China, and beyond. Even so, Tsai manages to keep an extremely low profile.">