Jamie Dimon, JPMorgan Chase chief executive, warned on Wednesday that loss rates on the credit card loans of Washington Mutual, the troubled bank acquired last year by JPMorgan, could climb to 24 per cent by the year end.

In the past, credit card loss rates have tracked the unemployment rate but that relationship has been breaking down for more troubled credit card portfolios, such as the $25.9bn in WaMu credit card loans.