Wells Fargo & Co. Chief Executive Officer John Stumpf said managing low interest rates may be the most pressing challenge for bankers and that his company had prematurely kept funds idle to gird for increases.

“One of the biggest risks today in our industry is not credit risk; it's interest-rate risk,” Stumpf said today at an investor conference in New York sponsored by the Sanford C. Bernstein & Co. research firm.

Investors have pressed bankers on how their firms can increase lending profit margins in a low-rate environment and drive up stock prices. Some banks have been wary of taking on business with rates hovering near record lows on concern loans will become less valuable when more-normal conditions return. Wells Fargo, based in San Francisco, is the largest U.S. home lender and ranks fourth by assets.