Does the Potential to Merge Reduce Competition?

We study anticompetitive horizontal mergers in a dynamic model with noisy collusion. At each instant, firms either privately choose output levels or merge to form a monopoly, trading off the benefits of avoiding price wars against the costs of merging. The potential to merge decreases pre-merger collusion, as punishments effected by price wars are weakened. We thus extend the result of Davidson and Deneckere [Davidson C, Deneckere R (1984) Horizontal mergers and collusive behavior. Internat. J. Indust. Organ. 2(2):117–132.], who analyzed the weakening of punishments post-merger, demonstrating that pre-merger collusion is weakened, in a fully stochastic model. Thus, although anticompetitive mergers harm competition ex post, the implication is that barriers and costs of merging due to regulation should be reduced to promote competition exante.