Quantitative Methods for Evaluating the Unilateral Effects of Mergers

We describe the quantitative modeling techniques that are used in horizontal merger review for the evaluation of unilateral effects, and discuss how the 2010 Horizontal Merger Guidelines helped legitimize these methods and motivate scholarly research. We cover markets that feature differentiated-products pricing, auctions and negotiations, and homogeneous products, in turn. We also develop connections between quantitative modeling and market concentration screens based on the Herfindahl-Hirschman Index (HHI).