5) Mark Zuckerberg (Age: 30; Net worth: $33.4 billion)

Mark Zuckerberg is the founder and CEO of Facebook. The social media giant’s revenue grew 58 percent in 2014 to $12.5 billion, supported by a spurt in mobile ads. Zuckerberg is working on turning virtual reality headset maker Oculus VR, for which he paid $2 billion in 2014, into a next generation computing platform.