The 14 youngest billionaires on The Forbes 400 make up just 3.5 percent of list.<br />Nine of these 14 folks under 40 are tech entrepreneurs; the rest inherited their fortunes.<br />The youngest member of The Forbes 400 for the second year in a row is 26-year-old Snap Inc. (formerly Snapchat) CEO Evan Spiegel.<br />The richest member of the under-40′s is also the fourth richest person in the country: 32-year-old Facebook CEO Mark Zuckerberg with a fortune of $55.5 billion.<br />32-year-old Dustin Moskovitz, who cofounded Facebook with Zuckerberg, and Napster cofounder Sean Parker, 36, who was an early Facebook investor and briefly president of the company, also made the list.<br />Airbnb cofounders Brian Chesky, 35, Joe Gebbia, 35, and Nathan Blecharczyk, 33, made the list.<br />Ubiquiti Networks founder Robert Pera, 38, who got his start at Apple in 2003 but struck out on his own two years later earned a spot as well.<br />The only newcomer under the age of 40 is Walmart heir Lukas Walton.
