Interchange fees and incentives to invest in payment card systems

Interchange fees are interbank transfers that are used by payment platforms to allocate the total cost of a payment card transaction between the cardholder's bank (the Issuer) and the merchant's bank (the Acquirer). Each time a consumer pays by card, the Issuer of the card pays an interchange fee to the Acquirer of the transaction. In this paper, I study how banks' investments in payment card systems impact the privately and the socially optimal interchange fees. I show that if the Acquirer's contribution to investments is high, and if the consumers benefit more than the merchants from investments, the payment platform may decide to lower the interchange fee so as to encourage banks' investments in quality.