An online merchant who wants to offer online bank transfers must contact an appropriate "Acquirer" (credit institution that clears credit card payments for merchants). This will be the contact for the business prerequisites and will decide whether the business model in question meets requirements. Usually the "Acquirer" will be the merchant's local in-country bank.

Besides the Acquirer, an additional contract must be concluded with a Payment Service Provider, who supplies the technical connection between shop and Acquirer.

Online merchants wishing to offer online bank transfers, but without dealing with acquirers and Payment Service Providers directly, can use special service providers such as Pay4. Pay4 has longstanding contacts with most important European Acquirers and takes care of the business relationship with the bank, as well as the payment transfer connection between shop and bank.

This provides international and overseas merchants a chance to offer their customers the appropriate local online bank transfer methods, e.g. in Europe, without making all the necessary contacts themselves, and negotiating, possibly in a foreign language. This allows them to significantly extend their sales reach and thus increase sales in target markets with online bank transfers.