ATM surcharge bans and bank market structure: The case of Iowa and its neighbors

It is frequently claimed that high ATM surcharges actually attract customers to the banks that impose them, particularly if they operate large ATM networks. By exploiting as “natural experiments” two events associated with the lifting of surcharge bans in Iowa and in the states that neighbor Iowa, this paper seeks to test for the implications of this phenomenon as it applies to the market shares of banking institutions and to several aspects of market structure. Consistent with predictions, results of “difference-in-difference” analyses suggest that the retail account shares of larger market participants increased relative to those of smaller competitors, market concentration increased, and the number of market competitors decreased after the lifting of surcharge bans – all relative to what would have occurred had there been no change in authority to surcharge.