has given permission. Limits interest rate increases on past balances to cases in which the account has been over 60 days late. Limits general interest rate increases to 45 days after a written notice is given, allowing the consumer to opt out. Requires extra payments to be applied to the highest-interest rate sub-balance. Truth in Lending Act In the United States, there are four commonly accepted methods of charging interest, which are listed in the section below, "Methods of Charging Interest". These are detailed in RegulationZ of the Truth in Lending Act. There is a legal obligation on U.S. issuers that the method of charging interest is disclosed and is sufficiently transparent to be fair. This is typically done in the Schumer box, which lists rates and terms in writing to the cardholder applicant in a standard format. RegulationZ details four principal methods of calculating interest. For purposes of comparison between rates, the "expected rate" is the APR applied to the average daily balance for a year, or in other words, the interest charged on the actual balance left lent out by the bank at the close of each business day. That said, there are not just four prescribed ways to charge interest, to wit those specified in RegulationZ. U.S. issuers can charge interest according to any reasonable method to which the card holder agrees. The four (or arguably six) "safe-harbour" ways to describe and charge interest are detailed in RegulationZ. If an issuer charges interest in one of these ways then there is a shorthand description of that method in RegulationZ that can be used. If a lender uses that description, and charges interest in that way, then their disclosure is deemed to be sufficiently transparent and fair. If not, then they must provide an explanation of the method used. Because of the safe-harbour definitions, U.S. lenders have tended to gravitate towards these methods of charging and describing the way interest is charged, both because it is easy and because legal compliance is guaranteed. Arguably, the approach also provides flexibility for issuers, enhancing the profile of the way in which interest is charged, and therefore increasing the scope for product differentiation on what is, after all, a key product feature. Pre-payment penalties Clauses calling for a penalty for paying more than the contracted regular payment were once common in another type of loan, the installment loan, and they are