NBER Working Papers by Daniel Hosken

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.

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.

In this paper we propose a method to evaluate the effectiveness of U.S. horizontal merger policy and apply it to the study of five recent consumer product mergers. We selected the mergers from those that, from the public record, seemed to be most problematic for the antitrust agencies. Thus we estimate an upper bound on the likely price effect of completed mergers. Our study employs retail scanner data and uses familiar panel data program evaluation procedures to measure price changes. Our results indicate that four of the five mergers resulted in some increases in consumer prices, while the fifth merger had little effect.