A fee paid by an acquirer to an issuer for transactions entered into interchange. The interchange fee is a percentage applied, according to Visa/MasterCard regulations, to the dollar value of each transaction. There are multiple categories of interchange, and Visa and MasterCard each have their own criteria for their own categories. A transaction must meet the specified criteria for a category in order for that category's rate to be applied. Each transaction is evaluated individually, so various interchange rates may apply within one batch of merchant transactions.