This paper examines the optimal use of remedies and the efficiency defense for merger control. We develop a framework in which merger efficiency gains are endogenously determined and are not observed by the Competition Authority. The possibility of an efficiency defense can push firms to design...

This paper contributes to the economic analysis of merger control by taking into account the efficiency gains for the design of structural merger remedies when the competition authorities do not observe the magnitude of efficiency gains. We show that whenever divestitures are necessary, the...