We study the optimal timing of merger control by comparing the pre-and post closing enforcement. Mergers have both pro … endogenous: it depends on the timing of the merger control, as well as on some investment in evidence production. The ex post … enforcement turns out optimal whenever the costs of providing veri…able information on both efficiency gains and market power are …

-theoretic oligopoly theory, has become the dominating paradigm both in the U.S. (since the 1990s Post-Chicago movement) and in the EU (so …

This paper provides a comparative analysis of methods for the empirical ex post evaluation of merger control decisions … about the effects of systematic impact evaluations of merger decisions. I like to thank the participants of the OECD … Roundtable „Impact Evaluation of Merger Decisions“ (Paris, Juni 2011), Arndt Christiansen and Knud Sinding for valua-ble comments …