accounts have been open. However, the bank does not promise to pay the overdraft even if the automated criteria are met. Bounce protection plans have some superficial similarities to overdraft lines of credit and ad hoc coverage of overdrafts, but tend to operate under different rules. Like an overdraft line of credit, the balance of the bounce protection plan may be viewable as part of the customer's available balance, yet the bank reserves the right to refuse payment of an overdrawn item, as with traditional ad hoc coverage. Banks typically charge a one-time fee for each overdraft paid. A bank may also charge a recurring daily fee for each day during which the account has a negative balance. Critics argue that because funds are advanced to a consumer and repayment is expected, bounce protection is a type of loan. Because banks are not contractually obligated to cover the overdrafts, "bounce protection" is not regulated by the Truth in Lending Act, which prohibits certain deceptive advertisements and requires disclosure of the terms of loans. Historically, bounce protection could be added to a consumer's account without his or her permission or knowledge. Transaction processing order An area of controversy with regards to overdraft fees is the order in which a bank posts transactions to a customer's account. Processing debits from largest to smallest will maximize the number (but not necessarily value—see subset sum problem) of overdrawn debits on a customer's account. This situation can arise when the account holder makes a number of small debits for which there are sufficient funds in the account at the time of purchase. Later, the account holder makes a large debit that overdraws the account (either accidentally or intentionally). If all of the items present for payment to the account on the same day, and the bank processes the largest transaction first, multiple overdrafts can result. The "biggest check first" policy is common among large U.S. banks. Banks argue that this is done to prevent a customer's most important transactions (such as a rent or mortgage check, or utility payment) from being returned unpaid, despite some such transactions being guaranteed. Consumers have attempted to litigate to prevent this practice, arguing that banks use "biggest check first" to manipulate the order of transactions to artificially trigger more overdraft fees to collect. Banks in the United States are mostly regulated by the Office of the Comptroller of the