40 under 40

Our 2013 edition of the list features young hotshots who are rocking businesses as diverse as air travel, natural gas, and genetic coding, as well as—if you can believe it— government.

3. Mark Zuckerberg

40u40 mark zuckerberg
  • Age: 29
  • Title: Founder and CEO
  • Company: Facebook

It took 14 months, but shares of the social network finally topped their initial public offering price of $38 late this summer (now they're even higher). That's because Zuckerberg's mobile strategy at last appears to be working. Mobile-ad sales now account for 41% of Facebook's total ad revenue, and the number of people posting photos and status updates on the go surged 51% in the most recent quarter. Facebook is also reportedly planning to launch TV-style ads that will cost brands up to $2.5 million a day. In other words, investors' confidence in Facebook—and Zuck—is back.

  @FortuneMagazine - Last updated September 30 2013 03:41 PM ET
Join the Conversation
Market indexes are shown in real time, except for the DJIA, which is delayed by two minutes. All times are ET. Disclaimer LIBOR Warning: Neither BBA Enterprises Limited, nor the BBA LIBOR Contributor Banks, nor Reuters, can be held liable for any irregularity or inaccuracy of BBA LIBOR. Disclaimer. Morningstar: © 2014 Morningstar, Inc. All Rights Reserved. Disclaimer The Dow Jones IndexesSM are proprietary to and distributed by Dow Jones & Company, Inc. and have been licensed for use. All content of the Dow Jones IndexesSM © 2014 is proprietary to Dow Jones & Company, Inc. Chicago Mercantile Association. The market data is the property of Chicago Mercantile Exchange Inc. and its licensors. All rights reserved. FactSet Research Systems Inc. 2014. All rights reserved. Most stock quote data provided by BATS.