As if subprime losses are not enough, big banks including HSBC know they are pushing the limit of credibility on credit card balances. Writeoffs are up 48 percent. The largest credit-card banks each set aside $1 billion to $3.5 billion in the third quarter for losses on card loans as their profits plummeted. The biggest credit-card lenders include Discover Financial Services, Bank of America Corp., Citigroup, JPMorgan Chase & Co., Capital One Financial Corp., American Express Co. and HSBC Holdings.

