A wire transfer is the direct transfer of funds from the payer's account at one bank to the payee's account at another bank. This is the most rapid form of payment, but is also the most expensive. Banks typically charge high fees to both the payer and the payee.
Despite the supposedly fast payment time of a wire transfer, funds may not be available in the payee's bank account for several days, particularly when the initiating bank does not have a direct correspondent relationship with the receiving bank; in this case, it must route the payment through a third bank that does have a correspondent relationship with the receiving bank.
The time of day when a wire is initiated can be a factor in delayed payments; if the wire initiation is near the close of business, then the banks may add an extra day to the transaction.