"It will be a different business," said Edward L. Yingling, the chief executive of the American Bankers Association, "Those that manage their credit well will in some degree subsidize those that have credit problems."

A 2005 report by the Government Accountability Office estimated that 70 percent of card issuers' revenue came from interest charges, and the portion from penalty rates appeared to be growing. The remainder came from fees on cardholders as well as retailers for processing transactions. Consumer advocates say they have little sympathy for credit card issuers, arguing that they have made billions in recent years with unfair and sometimes deceptive practices.