A stop payment is a request made to an entity's bank to not honor a check that the entity has issued to a payee. The notice may need to be in writing. The bank will then enter a block flag into its accounting system that will reject the check when it is presented for payment. The bank charges a fee for this service, which is deducted from the entity's bank account. If the bank then pays the check to a payee, the bank is liable to the payer for the amount of the check.
There are several reasons why a stop payment may be issued. For example, the accounts payable staff may have learned that they paid the wrong amount, or sent the original check to the wrong address.