What is the highest interest rate allowed by law for an unpaid credit card?

There are state usury maximums. If the credit card is issued by a "national" or federal bank there is basically no ceiling, thanks to a combination of a 1978 supreme court ruling and other laws passed in the late eighties.(wow, not Clinton's fault). Search the web for usury (most people misspell it "usery") for a pleothora of info.

I think it depends which bank's card you are using and how you are bargain with them. http://bit.ly/8KA8Dh