DP7077 Dynamic Merger Review

Author(s):	Volker Nocke, Michael Whinston
Publication Date:	December 2008
Keyword(s):	efficiency gain, horizontal merger, market power, merger policy, oligopoly
JEL(s):	D43, L13, L41
Programme Areas:	Industrial Organization
Link to this Page:	cepr.org/active/publications/discussion_papers/dp.php?dpno=7077

We analyze the optimal dynamic policy of an antitrust authority towards horizontal mergers when merger proposals are endogenous and occur over time. Approving a currently proposed merger will affect the profitability and welfare effects of potential future mergers, the characteristics of which may not yet be known to the antitrust authority. We show that, in many cases, this apparently difficult problem has a simple resolution: an antitrust authority can maximize discounted consumer surplus by using a completely myopic merger review policy that approves a merger today if and only if it does not lower consumer surplus given the current market structure.