The Consumer Financial Protection Bureau said that it has sent letters to major retail credit card companies to reconsider a pricing method some of them are using because it may “lack transparency to consumers,” MarketWatch.com reported yesterday. The CFPB also said consumers can file complaints about credit cards to the Bureau online. “Deferred interest” means they offer no interest for a set period of time, as long as the balance is paid in full by the end of that promotional period. For consumers who are able to pay that balance off, a deferred-interest card can then be a viable option. The problem, the bureau said: Many consumers do not realize they will be charged interest retroactively on all the purchase made during the promotional period if they do not pay the balance in full. And it may not be clear from reading the cards’ terms that this is the case.