13: Michael Rubin — Philadelphia 76ers ($2.9 billion)

Age: 47

Nationality: American

How he made his fortune: Rubin started his career as a teenager when he opened a ski shop in Pennsylvania, using money from his bar mitzvah, according to People.

After his ski empire grew, Rubin went on to create athletic equipment brand KPR sports, and later e-commerce company, GSI Commerce, which he sold to eBay in 2011 for $2.4 billion.

Titles won as owner: N/a.