article_snippet: Facebook's Mark Zuckerberg jumped five spots to number 16,
article_snippet: Snapchat's Evan Spiegel, 24, is the world's youngest billionaire while Uber co-founders, Travis Kalanick and Garrett Camp, and their first employee, Ryan Graves, also made up the under-40s group.
article_snippet: Tom Persson, 30 - H&M ($3bn) 5.
article_snippet: Nathan Blecharczyk, 31 - Airbnb ($1.9bn)
article_snippet: Evan Spiegel, 24 - Snapchat ($1.5bn
article_snippet: Bobby Murphy, 25 - Snapchat ($1.5bn)
article_snippet: Snapchat's Evan Spiegel, 24, is the world's youngest billionaire (left).