248. Bobby Murphy
$3.1 billion self-made score: * source: snapchat age: 29 residence: venice, calif. B.s., stanford ’10 Stanford fraternity brothers Spiegel and Murphy cofounded Snapchat in 2011. Their messaging company, now called Snap, has had a rocky ride since it went public in March. The stock fell more than 40% through late September as user growth slowed and Instagram launched copycat features. Murphy, who studied math and computational science in college, is Snap’s chief technology officer. Spiegel, who dropped out of Stanford a few weeks before graduation, is the only Forbes 400 member under age 30 who’s also CEO of a publicly traded company.