Mr. Leder is virtually unknown outside financial circles. But from his headquarters in Boca Raton, Fla., he presides over a multibillion-dollar private empire. Mr. Romney was an early investor in some of the deals done by Mr. Leder’s investment company, Sun Capital, which today oversees about $8 billion in equity. He and another banker, Rodger R. Krouse, were working at Lehman Brothers when they saw the huge money-making potential of private equity. They hatched their plan to get into the business one April afternoon in 1995, after a meeting at Mr. Romney’s Bain Capital in Boston. Mr. Leder and Mr. Krouse both lost money that they had personally invested with Bernard L. Madoff. Mr. Leder and his wife of 22 years, Lisa, began to go through a messy divorce. She demanded half of his total wealth, which she contended was more than $400 million at the time. The two eventually settled for an undisclosed amount. Last July, he used part of his personal fortune to join a group of investors in buying the Philadelphia 76ers. Prior to co-founding Sun Capital Partners in 1995, Mr. Leder served as a Senior Vice President of Lehman Brothers in New York. Mr. Leder received a Bachelor of Science degree in Economics from the Wharton School of the University of Pennsylvania and serves as a member of the University of Pennsylvania Huntsman Program Advisory Board.