Are you a PNC customer with a complaint about your bank? William Demchak, the chief executive of PNC Financial Services Group (PNC), might want to take your call.

"I had the fortunate, or unfortunate, experience of having my cellphone number put out on the web, so I actually get many complaints directly to my cellphone — which I answer fairly often," Demchak said during a panel discussion at a banking conference on Thursday.

Demchak did not say how or when his personal number wound up online, but he seemed surprisingly sanguine about the leak. Now he says he uses the customer calls as a sort of immediate focus group for how his bank is doing.

"You tend to learn a lot. Eighty percent of [the calls], you hand them off, because somebody needs to fix something. But 20% of the time you actually learn something about the behavior of your firm, that you think you ought to change," Demchak said. "Either the speed of service or people down in layers aren't making empowered decisions to fix something you know they ought to fix."

Demchak, who took over as PNC CEO in April, was speaking at a New York conference hosted by The Clearing House.