Significant attention worldwide has been paid to the regulation of credit card interchange fees. In part, this attention has followed concerns expressed about the level of these fees in Europe, the U.S. and Australia. The Reserve Bank of Australia recently conducted an extensive inquiry into the interchange fees associated with credit cards and has moved to regulate those fees. At the same time, research economists have considered determinants of the socially optimal interchange fee. In this paper, we use the Australian experience to highlight alternative methods of regulating interchange fees in payments systems. We use a simple model to derive a socially optimal interchange fee when merchants cannot freely set different prices for different payment instruments. We compare the socially optimal interchange fee from this model with those presented in the economics literature and show that most analyses capture a simple externality within the optimal fee. Credit card usage for a specific transaction is determined by the customer. But the customer does not bear the costs or receive the benefits that card usage imposes on the merchant. The optimal interchange fee internalises this externality. We then compare the theoretical optimal interchange fee with the approaches proposed in Australia, and show that the regulatory approach adopted by the Reserve Bank of Australia may be viewed as economically conservative in certain situations. Finally, we consider additional issues that will impinge on the regulation of interchange fees.
Available at: http://works.bepress.com/joshuagans/29/