Facebook co-founder Dustin Moskovitz, 30, is the youngest billionaire in the Forbes 400 richest Americans list of 2014. His Harvard University roommate and Facebook founder Mark Zuckerberg who is just eight days older is the second youngest billionaire on the list.
Mr Moskovitz, who left Facebook in 2008 to start software firm Asana is worth $8.1 billion dollar according Forbes' estimates. Facebook CEO Mr Zuckerberg's fortune is more than four times his former roommate's at $34 billion.
Sean Parker, founding president of Facebook completes the trio for the 'social network' at fifth position on the list with a net worth of $3 billion. Mr Parker had also founded online music firm Napster.
Out of the 400 people on Forbes' list of the richest in the United States in 2014, 11 are under the age of 40. (See full list)
Another 30-year-old who makes it to the list is Elizabeth Holmes, founder of California-based blood testing company Theranos. Ms Holmes, who had dropped out of Stanford University to start her venture from money saved for college, is the third youngest billionaire on the list.
Rounding off the list of the top five, is 31-year-old energy pipeline heir Scott Duncan with a net worth of $7 billion.