Sweeping credit card reform goes into effect Monday, which prevents credit card companies from imposing sudden rate hikes and excessive fees.
The new law also requires statements to inform consumers just how long it will take to pay off the balance by paying only the minimum monthly amount.
"Jaws will drop," said David Robertson, publisher of The Nilson Report, a newsletter that tracks the industry. "I don't doubt for a nanosecond that it's going to give a lot of people a sinking feeling in their stomachs."
The new legislation will make it more difficult for millions of Americans to get credit, since credit card companies increased interest rates, created new fees and cut credit lines during the past nine months.
Critics say the bill still allows banks to increase their fees and impose harsh terms on loans.
"We expected some rate increases; we expected some annual fees," said Ed Mierzwinski of the U.S. Public Interest Research Group, an advocacy organization that lobbied for the law.