Bank of America told thousands of its cardholders in recent weeks — even those with good payment histories — that they faced a rate hike from 9 percent to as high as 28 percent if they didn't pay off their balances at the old rate and stop using their cards. The bank, the largest credit card issuer, since its 2006 acquisition of MBNA, says it's all part of its "periodic" review of customer credit risk, according to Forbes.