A retroactive APR increase occurs when your credit card issuer increases your APR on not just future purchases, but on your existing balance as well. The CARD Act was initially believed to have ended retroactive rate increases, but that was not entirely accurate. The CARD Act did restrict a credit card company’s ability to raise your APR on previous purchases if you’re making your payments on time. However, if you fall more than 60 days behind on your credit card bill, a retroactive interest rate increase is still on the table. Your card issuer can implement a retroactive APR on your past-due balance if you miss payments. In fact, if you fall far enough behind on your credit card payments, your card issuer may also increase your APR to the maximum rate allowed under your credit card agreement. This is known as the default rate and is usually in the neighborhood of 30%. Compare that to the average credit card interest rate of around 15%, according to the Federal Reserve. Falling behind on your credit card payments and then seeing your interest rate increase to the default rate can be a very discouraging experience. But federal law gives you the opportunity to turn things around. But, as expected, this is going to involve making payments on time.