Net worth: $73.1 billion

Age: 53

Country: US

Industry: Tech

Source of wealth: Self-made; Amazon.com

Jeff Bezos earned his massive fortune by introducing e-commerce to the world. After spending time in finance on Wall Street, Bezos founded Amazon.com in the garage of his Seattle home in 1994 and operated it exclusively as an online book retailer. The company went public three years later and has since grown to include everything from furniture to food to Amazon's own consumer-electronics products, generating $136 billion in revenue in 2016.

Bezos also has interests outside of Amazon, including investments in his privately owned space company Blue Origin, which successfully launched its first spacecraft in 2015, and The Washington Post, the newspaper he bought in 2013. 

Bezos' wealth has increased by $21.9 billion in the last year.