the customer's account would have shown the pending transaction from the authorization at the beginning of service. The settled charges will be deducted from the authorized funds and are not in addition to the authorized funds. Both car rental and hotel incidental holds can be kept by the merchant for up to 30 days from the date of original charge. In most cases, the merchant determines the amount of the hold, and the card issuing company determines the length of time it takes before the hold is released. Double holds On occasion, negligence or computer error may make a merchant attempt to authorize a card twice, creating a double hold on the cardholder's bank account. That often happens when a processor requires additional security verification such as a card security code, ZIP code, or address, and incorrect information is provided or is mistyped. Gasoline pumps often impose a double hold, one for a standard amount (such as $75) and another for the amount of purchase. Though the merchant will settle the transaction only once, the hold will temporarily lower the customer's available balance, potentially causing declines or, for a debit card, even overdrafts. Voided transactions Only merchants have the ability to reverse preauthorizations on a cardholder's account. Reversals are not required by most regulations before the authorization expires automatically, so the hold will remain on the account, allowing whatever entity holding the amount (a bank, usually) to invest it and make a profit via interest. Rarely, banks will remove authorization holds with a written request from the authorizing merchant. Since most banks cannot verify that the letter from the merchant is someone who has authority to ensure that the charge will not settle, they require the hold to remain according to their bank policies. Holds for differing amounts Another issue that occurs on a regular basis with authorization holds is the transaction amount changing between the time the hold is placed on the account and when the transaction is settled. It most commonly occurs when the final debit amount is uncertain when the authorization is actually obtained. For example, if an individual makes a fuel purchase by swiping a check card or credit card at the pump without using the PIN, the pump has no way of knowing how much fuel will be used. The pump typically authorizes a fixed amount, usually $1 but sometimes up to $100, to verify