17) Joe Gebbia (Age: 33; Net worth: $1.9 billion)

Joe is the co-founder and chief product officer of Airbnb, a peer-to-peer home and apartment rental company which has served 30 million guests since its inception. He came up with the idea with co-founder Brian Chesky in 2008 after graduating from the Rhode Island School of Design. He owns around 15 percent of the company.

16) Brian Chesky (Age: 33; Net worth: $1.9 billion)

Co-founder and CEO of Airbnb, Brian Chesky, is a former body builder. His company was valued at $13 billion in October 2014 after an employee stock sale. Airbnb is a six-year-old peer-to-peer home and apartment rental company.