The U.S. Horizontal Merger Guidelines and guidelines issued by enforcement agencies around the world employ the hypothetical monopolist paradigm to delineate relevant markets, but they provide only an imprecise and incomplete algorithm for implementing that paradigm. This paper fills the gap by...

"Critical elasticity of demand" and "critical loss" analysis are now standard analytical tools for implementing the hypothetical monopolist paradigm for market delineation. Although these tools are highly useful, this paper presents three scenarios in which their standard application can be...