The “issuer” is usually defined as the undertaking acting as the payment service provider of the payer (consumer or business) who issues payment cards or other payment instruments to the payer and processes payments initiated with these cards or other instruments. The payment cards or payment instruments are issued as part of a 4-party system. The counterpart to the issuer is the acquirer, who acts as the payment service provider of the payee and collects payments by means of payment cards and other payment instruments.