America's Youngest Billionaires

Facebook catapults three 20-somethings onto the list, but the youngest isn't who you think it is.
Dustin Moskovitz

Net Worth: $1.4 billion   
Source: Facebook
Age: 26
America's youngest billionaire is eight days younger than his former Harvard roommate Mark Zuckerberg. Facebook's first chief technology officer, he left in 2008 to start Asana, a software company that allows individuals and small companies to better collaborate. The company has attracted several of the same early backers as Facebook and may one day be worth something. For now, though, Forbes estimates Moskovitz's entire $1.4 billion fortune comes from his 6 percent stake in Facebook.

Mark Zuckerberg

Zuckerberg may no longer reign as the youngest member of the Forbes 400, but he has bragging rights as the year's biggest percentage gainer -- his net worth jumped to $6.9 billion, up from $2 billion, making him worth nearly five times as much as Moskovitz and more than even Apple's (Nasdaq: AAPL - News) Steve Jobs.

Eduardo Saverin

The third Facebook co-founder among the ranks is 28-year-old Eduardo Saverin, who once owned a one-third stake in Facebook. When Zuckerberg and Moskovitz quit school to relocate to California, Saverin stayed behind to graduate. A year later Facebook sued him; he countersued. The parties settled with Saverin apparently getting a 5 percent stake and a co-founder bio on Facebook's site. Don't feel bad. We estimate that share makes him worth $1.15 billion.
 

©J. Scott Applewhite/APJohn Arnold
Net Worth: $3.3 billion
Source: hedge funds
Age: 36
The former Enron oil trader founded hedge fund Centaurus after the energy outfit famously collapsed. His fund now has $5 billion under management, and he and his wife Laura recently pledged half of their wealth to the Gates-Buffet challenge.

©Courtesy of Google

Sergey Brin

Net Worth: $15 billion
Source: Google
Age: 37

Emigrated from Russia at age 6; his mother was a research scientist at NASA. He met Larry Page in computer science Ph.D. program at Stanford and dropped out in 1998 to start Google. Brin now focuses on raising margins with Instant Search and building new businesses in communications, and he invests in space travel initiatives and Parkinson's research on the side.

©Courtesy of Google

Larry Page

Net Worth: $15 billion
Source: Google
Age: 37

The Google co-founder dropped out of his Stanford Ph.D. program in 1998 to start the search engine. Nowadays his personal passions include buying up chunks of residential Palo Alto for a network of houses that use new types of fuel cells, geothermal energy and rainwater capture. He also rides a Zero X electric dirt bike and an electric sports car from Tesla Motors, in which he and Sergey Brin are investors. Page is a board member of the X Prize Foundation, a nonprofit looking for breakthroughs in genomics, energy and space exploration.

©Victoria Will/Splash News/Newscom

Daniel Ziff

Net Worth: $4 billion
Source: inheritance, hedge funds
Age: 38

The youngest son of the late William Ziff Jr., who built the Ziff-Davis publishing empire (PC Magazine, Car & Driver, Boating) and later sold out. Daniel and his brothers Dirk and Robert inherited their father's fortune, which they have since reinvested in Ziff Brothers Investments. He recently got married.

©Eric Jamison/AP

Lorenzo Fertitta

Net Worth: $1 billion
Source: casinos, Ultimate Fighting Championship
Age: 41

Fertitta returns to billionaire status thanks to growing martial arts league Ultimate Fighting Championship, which he owns with his older brother Frank. Abu Dhabi investment is helping UFC go international. A scuba diver, he swims with sharks -- including tigers and great whites -- for fun.

©J. Scott Applewhite/AP

Jerry Yang
Net Worth: $1.15 billion
Source: Yahoo!
Age: 41
Born in Taiwan, Yang moved to the U.S. at age 10. He created his Web directory in 1994 with partner David Filo when both were Stanford grad students. Yahoo! co-founder made his debut among America's 400 richest at age 29. Still with Yahoo!, but no longer its head honcho. He sits on other boards and makes a number of charitable donations.
Forbes.com