1. Bill Gates
Net worth: $79.2 billion
Bill Gates co-founded Microsoft in 1975 and it blew up to become the biggest software company on the planet.
He has been selling shares of the company gradually over the last 15 years. Gates stepped down as CEO of Microsoft in 2000 and was succeeded by Steve Ballmer. He later stepped down as chairman of the company last year, and has sold one-third of his remaining stake in the company over the course of the last year, meaning he is no longer the company's biggest shareholder for the first time in its history.
Today, the 59-year-old Gates serves as an adviser to current CEO Satya Nadella, and works full time for the Bill & Melinda Gates Foundation.
Forbes said Bill Gates is the richest person in the world, and he has held that title for 16 out of the last 21 years.