There is a long history of governmental efforts to protect personal privacy and strong debates about the merits of such policies. A central element of privacy is the ability to control the dissemination of personally identifiable data to private parties. Posner, Stigler, and others have argued...

In many markets, including payment cards and telecommunications, service providers operate networks that support customer transactions with each other. When the two sides of a transaction belong to more than one network in common, the question arises as to which network will carry the...