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

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

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

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