The acquirer is usually the payment service provider of the payee (usually a retailer) who collects payments for the payee by way of payment cards or other payment instruments issued within a four-party system.
The counterpart to the acquirer is the issuer, who acts as the payment service provider of the payer (cardholder) and who issues payment cards or other payment instruments to the payer.
The term “acquirer” has recently been generally used for the payee’s payment service providers who collect payments for the payee (pull payments).