9. Robert Pera
Age: 36
Net worth: $2.8 billion
Robert Pera used to work as a wireless engineer at Apple, but quit his job and started his own technology company Ubiquiti Networks. Now, he co-owns the NBA team Memphis Grizzlies with none other than Justin Timberlake. That’s quite an accomplishment for someone of any age, let alone someone under the age of 40.
