Consumers who keep their account in good order by always staying within their credit limit, and always making at least the minimum monthly payment will see interest as the biggest expense from their card provider. Those who are not so careful and regularly surpass their credit limit or are late in making payments are exposed to multiple charges that were typically as high as £25 - £35 until a ruling from the Office of Fair Trading that they would presume charges over £12 to be unfair which led the majority of card providers to reduce their fees to exactly that level.

US

The Credit CARD Protection Act of 2009, signed into law by President Obama, will require that consumers "opt-in" to over-limit charges. Consumers who choose not to opt-in will be unable to make purchases over the limit; the card will simply be declined and no fees will be imposed. This legislation will take effect on February 22, 2010.

UK

The higher level of fees originally charged were claimed to be designed to recoup the costs of the card operator's overall business and to ensure that the credit card business as a whole generated a profit, rather than simply recovering the cost to the provider of the limit breach which has been estimated as typically between £3-£4. Profiting from a customer's mistakes is arguably not permitted under UK common law, if the charges constitute penalties for breach of contract, or under the Unfair Terms In Consumer Regulations 1999.

Subsequent rulings in respect of personal current accounts suggest that the argument that these charges are penalties for breach of contract is weak, and given the OFT's ruling it seems unlikely that any further test case will take place.

Whilst the law remains in the balance, many consumers have made claims against their credit cards providers for the charges that they have incurred, plus interest that they would have earned had the money not been deducted from their account. It is likely that claims for amounts charged in excess of £12 will succeed, but claims for charges at the OFT's £12 threshold level are more contentious.