Efficiency Gains and Structural Remedies in Merger Control∗

This paper studies the role of structural remedies in merger control in a Cournot setting where (endogenous) mergers are motivated by prospective efficiency gains. Every merger has to be submitted to an Antitrust Authority (AA) which, apart from blocking or unconditionally approving it, might approve a modified version of the concentration where divestitures are required. Some important merger policy implications can be drawn. First, when divestitures are required, the AA over-fixes, i.e., goes beyond the recreation of the level of competition that existed prior to the transaction. Second, by insisting in overfixing, the AA may discourage firms to look for more efficient mergers. Finally, structural remedies are shown to open up new merger opportunities to firms.