Acquirers process credit and debit payments for merchants, making it possible for them to accept payment from card issuers that are within associations like Visa, MasterCard, Discover, and American Express. Acquirers can be banks or other financial institutions. The contract acquirers and merchants enter into give the merchant a line of credit in the form of a merchant account. This relationship is often facilitated by an independent sales organization (ISO), member service provider (MSP), or payment processor. The acquirer’s fees are a markup that gets added to association interchange fees.