Exposing the Credit-Card Fine Print

Hidden credit-card charges and soaring interest rates have consumers steamed. And Congress is finally listening

To credit-card companies, it's not sufficient that customers pay their bills on time every month; they must also avoid a daunting array of borrowing habits that lenders deem risky. Like borrowing. Katie Groves, 42, learned this firsthand when the annual interest rate on her Chase Visa bill jumped to 29.99%—from the previous 12%. Although she had never missed a payment and owed only $500, she was told that her rate had increased because Chase had checked her credit report.

Most consumers are unaware that the banks constantly monitor all their borrowing behavior. Even if you just get too close to your borrowing...