The hypothetical monopolist test has been used to define antitrust markets for over 20 years. However, many of these applications occur within the enforcement agencies and thus the implementation process is not fully transparent to antitrust practitioners. This paper provides a study of 116...

The 2010 Merger Guidelines appear to elevate game theoretic models of competitive concerns to the primary concern of merger policy, while reducing the importance of market definition. Although situations in which this change makes some sense exist, we observe that, as a practical matter, market...

This paper generalizes the critical loss concept of Harris and Simons to account for a broader range of possible cost structures. Our focus on understanding the market level equilibrium for relatively homogenous goods makes it clear that the Harris and Simons procedure is appropriate in some...

This paper generalizes the critical loss concept of Harris and Simons to account for a broader range of possible cost structures. Our analysis presents a specialized market-level equilibrium for a relatively homogeneous good in which the Harris and Simons’ critical loss structure is...

Market definition, a concept that has long served to structure competitive analysis, is under assault from theoreticians who object to the inability of the standard analysis to define a market compatible with their models of unilateral effects. Although these unilateral models have not been...

Sometimes what appears to be a little, almost imperceptible change can have a huge impact on a policy regime. The recently revised DOJ/FTC Horizontal Merger Guidelines contain such a change, as the document recognizes the importance of Critical Loss Analysis in defining a market, but introduces...