Concentration-based screens for horizontal mergers, such as those employed in the US DOJ and FTC Horizontal Merger … Guidelines, play a central role in merger analysis. However, the basis for these screens, in both form and level, remains unclear …

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 … surplus by using a completely myopic merger review policy that approves a merger today if and only if it does not lower …

merger wave. The evidence indicates that the efficiency of the majority of acquiring firms increases following an acquisition …. Based on the parameter estimates, we calculate merger welfare effects. We find that total welfare increased by $583 …

approximation for the market power effect of a merger. We also provide conditions under which a merger raises consumer surplus, and … conditions under which a myopic, consumer-surplus-based merger approval policy is dynamically optimal. Finally, we study the … aggregate surplus and external effects of a merger …

of merger activity. We find that hospitals gaining system members in-state (but not in the same geographic market …

This paper presents theory and evidence on horizontal industry structure, focusing on situations where plant …