Bill Gates
In 1986, Gates took Microsoft public. The company's stock was worth $520 million. Gates owned 45 percent of the stock himself, which was worth $234 million. The company continued its rapid growth and the stock price soared. At one point, Gates' stock was worth over $100 billion. This made him the richest man in the world, until October 2017, when Amazon founder and CEO Jeff Bezos became even richer than him.