Static and Dynamic Merger Effects: A Market Share Based Empirical Analysis

Abstract:     
Merger-specific efficiencies continue to play a relatively small role in merger enforcement and merger retrospectives. Motivated by the paucity of empirical analyses of merger-specific efficiencies, we examine a merger's market share effects. Standard merger theory predicts that if merger-specific efficiencies are present, the merged firm should regain market share in the long-run. We estimate short and long-run merger effects on market shares from the divestiture of Texaco's Canadian assets. We use a difference-in-difference specification that compares changes for the merging firm with changes for other vertically integrated firms in the same market. Our approach is a useful complement to across market comparisons, which are often hindered by the difficulty of finding control markets that experience the same supply and demand shocks as the treatment markets.

Number of Pages in PDF File: 33

Keywords: merger, concentration, market share, gasoline

JEL Classification: L41, L71, L2, L1

working papers series