The analysis of horizontal mergers hinges on a tradeoff between unilateral effectsand efficiency gains. The article examines the role of uncertainty (on theefficiency gains) in this tradeoff. Common wisdom is that the antitrust authoritiesshould be very cautious about random gains. Our results...

Most retrospective merger studies resort to the treatment effect approach, comparingthe price dynamics in a treatment group and in a control group. We propose asystematic method to construct the groups, which applies to any industry with spatialcompetition. The method is consistent with the fact...

We consider a simple tournament model in which individuals auto-select into the contest