278. Michael Rubin
Rubin’s sports retailer Fanatics closed a $1 billion funding round from Softbank in August, raising its valuation to $4.5 billion. Rubin previously sold GSI Commerce to ebay for $2.4 billion in 2011; as part of the deal, he paid $500 million for a majority ownership in 3 unwanted ebay businesses: flash-sales site Rue La La, Shoprunner—and Fanatics. Rubin, who opened his first ski-supply store at 14 in a strip mall, dropped out of Villanova to focus on his ski business, which by then had several locations.