The challenge of effective merger enforcement is tremendous. U.S. antitrust agencies must, by statute, quickly forecast … estimating the price effects of mergers. We also describe how evidence from merger retrospectives can be used to evaluate the …

in the Horizontal Merger Guidelines. Through a model of enforcement, we find that agencies challenge mergers they expect …

mergers. We then simulate a representative set of U.S. mergers in order to evaluate merger review thresholds. Our main … lenient 2010 merger guidelines and unharmed, on average, under enforcement of the more stringent 1982 merger guidelines. We …

, we present a method for measuring undisclosed merger activity that relies on financial accounting reporting requirements …

is data on the relevant market pre and post merger. The second is data on the specific predictions of the government … agencies about the market post-merger. A key point of this article is to stress how weak an analysis of only the first type of … post merger are surprisingly poor guides for analyzing merger policy. It is only when the second type of data is combined …

research in the areas of collusion and merger enforcement. Research relating to both collusion and mergers has made significant …-based measurement) and theoretical work in advancing our understanding of collusive and merger-related phenomena …

guidelines reflect a substantial consensus on the appropriate template for merger assessment. Nevertheless, official protocols …

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 …

In this paper we propose a method to evaluate the effectiveness of U.S. horizontal merger policy and apply it to the … merger had little effect …