Prior to August 20, 2009, how much notice was required before increasing a cardholder's interest rate?
One provision of the Credit CARD Act that's already in effect is a requirement that card issuers give 45 days' notice before increasing interest rates. Before this took effect, they were only required to give 15 days' notice, barely enough time for the average customer to consider what few options were available, such as negotiating a lower rate, opting out or paying the whole thing off. So more often than not, cardholders would simply keep their cards and resign themselves to the new rates.
SOURCE: 5 Ways to Respond to a Credit Card Interest Rate Increase | About.com