Justin Bieber
Justin Bieber

The 18-year-old Canadian sensation, whose 2010 concert movie Never Say Never made $100 million globally, invested an undisclosed amount in PhoneGuard, a mobile app maker that attempts to safeguard users by, among other things, preventing them from texting while driving. Bieber also starred in a series of public service announcements tied to the company.

@FortuneMagazine - Last updated March 29 2012: 1:47 PM ET
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