The Neutrality of Interchange Fees in Payment Systems

Abstract

There has been considerable public debate over the effect of interchange fees on credit card transactions. Regulators in Australia and Europe have argued that these fees can be set by banks to have an anticompetitive effect. In the US, it has been argued that these fees, together with a rule that prevents a surcharge for credit purchases, might create a cross subsidy between cash and credit customers. Academics have noted that, in particular circumstances, interchange fees have no real effects in the absence of such a no-surcharge rule. This paper considers two aspects of credit card interchange fees. First, it provides a general neutrality result. We show that in the absence of a no surcharge rule, interchange fees can never have any real effects. This result does not depend on the degree or nature of competition at either the bank or the merchant level. Second, we consider the potential for a bank with market power to manipulate interchange fees in the presence of a no-surcharge rule in order to raise bank profits. We show that such cross subsidisation is not profitable if there is adequate competition from 'cash only' merchants. We then consider the interaction between imperfectly competitive merchants that accept credit cards. For the special case of a single merchant, we provide both necessary and sufficient conditions on demand and the merchant's profit function for fee manipulation to be feasible. We then examine what occurs when there are multiple imperfectly competitive merchants; demonstrating that the profitability of any cross subsidisation depends critically on the nature of merchants' competitive interactions.