Mergers can generate demand side efficiencies that benefit customers in a number of ways, including procurement savings, transaction efficiencies, and quality improvements. We show that per-unit demand side efficiencies and marginal cost efficiencies of the same magnitude have an equivalent...

This chapter has been prepared for inclusion in the RESEARCH HANDBOOK ON THE ECONOMICS OF ANTITRUST LAW (Einer Elhauge, ed.). It first explains why unilateral effects may result from horizontal mergers, and then describes several key models that have been developed to gauge the likelihood and/or...

The 2010 Merger Guidelines give greater prominence to the concept of parallel accommodating conduct. Parallel accommodating conduct (PAC) has a long history in oligopoly theory, dating back more than seventy years. It is a type of coordinated conduct that does not require an agreement. Instead,...

We examine the role of private information on the impact of vertical mergers. A vertical merger can improve the information that is available to an upstream monopolist because, after the merger, the monopolist can observe the cost of its downstream merger partner. In the pre-merger world,...