Rubin made $150 million when GSI Commerce, the ecommerce company he built from scratch in 1999, sold to eBay for $2.4 billion in 2011. As part of the deal, Rubin paid $500 million in cash and loans for majority ownership of three GSI assets eBay didn't want to digest. Apparel retailer Fanatics, flash sales website Rue La La, and Amazon Prime competitor ShopRunner are now wrapped under Rubin's holding company Kynetic. In March 2011, eBay agreed to buy GSI for $2.4 billion. A lifelong entrepreneur, Michael Rubin opened a ski-tuning shop in his parent's Lafayette, Pa. basement at age 12. By high school, he ran his own chain of sports shops. Fanatics, of which he has 72%, was valued at $3.1 billion in a 2013 venture round. He is a minority owner of basketball's Philadelphia 76ers. Today, Rubin has a net worth of about $8 billion, according to the Bloomberg Billionaires Index. Seizing on the disruptive power of internet-based shopping, he has turned sports merchandiser Fanatics into an $18 billion powerhouse that sells everything from National Basketball Association jerseys to Kentucky Wildcat-themed portable barbecue grills. He owns about 40% of the company. Rubin, 49, built Fanatics out of scraps left over from a deal with eBay Inc. a decade ago. Now the Jacksonville, Florida-based firm -- which has tripled in value through multiple funding rounds over the past 12 months -- is using its newfound heft to become a disruptor. Last month, it dethroned Topps Co. as the go-to producer of baseball cards by reaching exclusive agreements with Major League Baseball and its players’ association. It also added agreements with the NBA and National Football League. “Fanatics came into the jersey and apparel space and absolutely took over,” said Mike Gioseffi, who co-hosts the podcast Sports Cards Nonsense. The speed and breadth of its recent moves into trading cards are “just unheard of.” Fanatics is seeking to expand even further, with plans to enter sports betting, ticketing and media, according to company management. The sports-gambling industry could be an especially ripe target. It’s in the midst of consolidation and takeovers three years after the U.S. Supreme Court overturned a 26-year-old law banning sports betting in a majority of states.