Net worth: $42.5 billion

Age: 43

Country: US

Industry: Technology

Source of wealth: Self-made; Google

As a Stanford PhD student in 1998, Larry Page teamed up with classmate Sergey Brin to create BackRub, an early search engine. The project eventually morphed into Google — now called Alphabet — one of the largest and farthest-reaching companies in the world, worth more than $581 billion. Over the past year, Page's personal net worth has increased by $4.3 billion.

Page oversaw major changes to Google's business structure in 2015, starting with the creation of Alphabet, the holding company that manages Google and all of its related ventures, including Nest, Calico, and Google X. Previously the chief executive of Google, Page moved up to helm Alphabet, which has its hands in everything from home automation to self-driving cars to prolonging human life. 

Page doesn't make a lot of splashy purchases, but the alternative-energy advocate does own an eco-friendly mansion in Palo Alto that uses geothermal energy and rainwater capture. He's also an avid kiteboarder.