Drew Houston

It's possible that Houston will regard 2018 as one of the most important years in his relatively young life. After 11 years running one of Silicon Valley's hottest startups, he finally took his popular cloud storage and workplace software company public in March. Wall Street cheered Dropbox's IPO, sending its shares up nearly 40% on opening day (they've climbed 13% since). With the successful offering, Dropbox's public market valuation jumped to $12.45 billion, surpassing the company's private valuation of $10 billion. Not bad for a guy who once famously rejected the late Steve Job's offer to sell Dropbox to Apple.