When Jeffrey Epstein was serving time in Florida for soliciting prostitution from a minor, he got a surprising visitor: James E. Staley, a top JPMorgan Chase executive and one of the highest-ranking figures on Wall Street.

Mr. Staley had good reason to maintain his relationship with Mr. Epstein, who received him at his Palm Beach office, where he had been permitted to serve some of his 13-month sentence in 2008 and 2009. Over the years, Mr. Epstein had funneled dozens of wealthy clients to Mr. Staley and his bank.

Mr. Epstein, who was charged this month with sex trafficking of teenage girls, liked to portray himself as a financial wizard, someone whose business and investing acumen made him indispensable to corporate executives and other leaders. But there is little evidence to support that notion. The financial services that Mr. Epstein dispensed appear to have been mostly pedestrian, and his list of clients small.

Mr. Epstein nonetheless managed to affix himself to a handful of prominent Wall Street veterans, including Mr. Staley, who is now chief executive of the British bank Barclays.