NEW YORK ( TheStreet) -- Wells Fargo (WFC - Get Report) CFO John Shrewsberry is sure the bank will make more money when interest rates go up, but he won't speculate about how much and when.

"It depends how fast, and it depends on what's going on economically, loan demand and deposit-flow wise," he explained in a presentation at Deutsche Bank's Global Financial Services Investor Conference in New York on Wednesday. "We could be going on for a long time before we get to what people describe as a normalized level of policy rates."

Shrewsberry's assessment addressed speculation that has dominated investor conferences this year, particularly those centered on finance companies. At the start of the year, many economists and traders said a June rate hike was likely, but now, with June under way and off the table, speculation is focused on September. Goldman Sachs' President Gary Cohn reaffirmed the bank's belief in a September liftoff on Tuesday, but the bank's chief economist, Jan Hatzius, cautioned that a later date may be more likely.

The timing of an interest-rate increase from the Federal Reserve is important to banks because it will boost revenue from lending. The Fed cut the target funds rate to around zero to bolster the economy during the financial crisis and hasn't raised it in the seven years since.

Consequently, banks have earned less money from making loans. Net interest margin, which gauges the profitability of credit lines, dropped to an average of 3.09 for the nation's largest banks in 2014 from a 10-year high of 3.89 in 2005, according to data analyzed by Bloomberg. 

Shrewsberry also discussed how the banking industry will compete as robo-advisors, peer-to-peer lenders, and other competitors vie for a larger shares of the market.

With regard to peer-to-peer lenders who have been touted for streamlining the underwriting and funding process, Shrewsberry is simultaneously respectful and cautious.

"I'll be interested to follow them through the rate cycle and through the credit cycle to see how robust these credit-decisioning tools really are, and to see what happens when customers are unable to repay," Shrewsberry said. 

Wells Fargo is one of the few banks actually increasing the number of its branches while its competitors are shuttering local offices to focus on mobile banking, which carries a higher profit margin. The branches are important to businesses, which like to handle large transactions in person, as well as to consumers who visit them for auto and mortgage loans, Wells Fargo says.