US antitrust policy takes as its objective consumer welfare, not total economic welfare. With that objective, Joe Bain's definition of entry barriers is more useful than George Stigler's or definitions based on economic welfare. It follows that economies of scale that involve sunk costs may...

This essay surveys the economic literature on interchange fees and the debate over whether interchange should be regulated and, if so, how. We consider, first, the operation of unitary payment systems, like American Express, in the context of the recent economic literature on two-sided markets,...

US antitrust policy takes as its objective consumer welfare, not total economic welfare. With that objective, Joe Bain's definition of entry barriers is more useful than George Stigler's or definitions based on economic welfare. It follows that economies of scale that involve sunk costs may...