This year, Zuckerberg, 26, added $4.9 billion to his fortunevaulting to #35 on the Forbes 400 with an estimated fortune of $6.9 billion. Why the jump? Recent private equity investments in Facebook valued the firm at around $23 billionmore than triple its 2009 value of $7 billion. Illiquid private shares in secondary markets point to an even richer valuation.
Steve Jobs ranks #42 on the list with a net worth of $6.1 billion; $1 billion higher than last year.