Matthew C. Weinberg

Department of Economics, Drexel University
3600 Market St, 7th Floor
Philadelphia, PA 19104

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NBER Working Papers and Publications

February 2014Did Robert Bork Understate the Competitive Impact of Mergers? Evidence from Consummated Mergers
with Orley C. Ashenfelter, Daniel Hosken: w19939
In The Antitrust Paradox, Robert Bork viewed most mergers as either competitively neutral or efficiency enhancing. In his view, only mergers creating a dominant firm or monopoly were likely to harm consumers. Bork was especially skeptical of oligopoly concerns resulting from mergers. In this paper, we provide a critique of Bork's views on merger policy from The Antitrust Paradox. Many of Bork's recommendations have been implemented over time and have improved merger analysis. Bork's proposed horizontal merger policy, however, was too permissive. In particular, the empirical record shows that mergers in oligopolistic markets can raise consumer prices.

Published: Orley Ashenfelter & Daniel Hosken & Matthew Weinberg, 2014. "Did Robert Bork Understate the Competitive Impact of Mergers? Evidence from Consummated Mergers," Journal of Law and Economics, University of Chicago Press, vol. 57(S3), pages S67 - S100. citation courtesy of

August 2013Efficiencies Brewed: Pricing and Consolidation in the U.S. Beer Industry
with Orley C. Ashenfelter, Daniel Hosken: w19353
Merger efficiencies provide the primary justification for why mergers of competitors may benefit consumers. Surprisingly, there is little evidence that efficiencies can offset incentives to raise prices following mergers. We estimate the effects of increased concentration and efficiencies on pricing by using panel scanner data and geographic variation in how the merger of Miller and Coors breweries was expected to increase concentration and reduce costs. All else equal, the average predicted increase in concentration lead to price increases of two percent, but at the mean this was offset by a nearly equal and opposite efficiency effect.

Published: Efficiencies brewed: pricing and consolidation in the US beer industry Orley C. Ashenfelter1, Daniel S. Hosken2 andMatthew C. Weinberg3 The RAND Journal of Economics Volume 46, Issue 2, pages 328–361, Summer 2015 citation courtesy of

October 2011The Price Effects of a Large Merger of Manufacturers: A Case Study of Maytag-Whirlpool
with Orley C. Ashenfelter, Daniel S. Hosken: w17476
Many experts speculate that U.S. antitrust policy towards horizontal mergers has been too lenient. We estimate the price effects of Whirlpool's acquisition of Maytag to provide new evidence on this debate. We compare price changes in appliance markets most affected by the merger to markets where concentration changed much less or not at all. We estimate price increases for dishwashers and relatively large price increases for clothes dryers, but no price effects for refrigerators or clothes washers. The combined firm's market share fell across all four affected categories and the number of distinct appliance products fell.

Published: Orley C. Ashenfelter & Daniel S. Hosken & Matthew C. Weinberg, 2013. "The Price Effects of a Large Merger of Manufacturers: A Case Study of Maytag-Whirlpool," American Economic Journal: Economic Policy, American Economic Association, vol. 5(1), pages 239-61, February. citation courtesy of

March 2009Generating Evidence to Guide Merger Enforcement
with Orley C. Ashenfelter, Daniel Hosken: w14798
The challenge of effective merger enforcement is tremendous. U.S. antitrust agencies must, by statute, quickly forecast the competitive effects of mergers that occur in virtually every sector of the economy to determine if mergers can proceed. Surprisingly, given the complexity of the regulators task, there is remarkably little empirical evidence on the effects of mergers to guide regulators. This paper describes the necessity of retrospective analysis of past mergers in building an empirical basis for antitrust enforcement, and provides guidance on the key measurement issues researchers confront in estimating the price effects of mergers. We also describe how evidence from merger retrospectives can be used to evaluate the economic models used to predict the competitive effects of mergers.

Published: Orley Ashenfelter & Daniel Hosken & Matthew Weinberg, 2009. "Generating Evidence to Guide Merger Enforcement," CPI Journal, Competition Policy International, vol. 5. citation courtesy of

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