Mr. Epstein’s wealth may have depended less on his math acumen than his connections to two men — Steven J. Hoffenberg, a onetime owner of The New York Post and a notorious fraudster later convicted of running a $460 million Ponzi scheme, and Leslie H. Wexner, the billionaire founder of retail chains including The Limited and the chief executive of the company that owns Victoria’s Secret.

Mr. Hoffenberg was Mr. Epstein’s partner in two ill-fated takeover bids in the 1980s, including one of Pan American World Airways, and would later claim that Mr. Epstein had been part of the scheme that landed him in jail — although Mr. Epstein was never charged. With Mr. Wexner, Mr. Epstein formed a financial and personal bond that baffled longtime associates of the wealthy retail magnate, who was his only publicly disclosed investor.

Mr. Epstein’s firm, Financial Trust Company, has released no audited financial statements or performance reports to back up his claims of investment prowess. In a 2002 court filing, Mr. Epstein said he had 20 employees, far fewer than reported figures around that time. Six years later, he lost large sums of money in the financial crisis. And friends and patrons — including Mr. Wexner — deserted him after he pleaded guilty to prostitution charges in 2008.