Bush, Clinton, Bush : Twenty Years of Merger Enforcement at the Federal Trade Commission

The Hart Scott Rodino program, coupled with the modern Merger Guidelines, has structured merger enforcement for the last twenty years. This paper tabulates and evaluates information from Federal Trade Commission merger reviews. While horizontal mergers predominate, vertical, potential competition and monopsony cases are represented in the sample. Over the years, the Commission has studied mergers in a broad range of industries, including branded consumer products, chemicals, hospitals, drugs, oil, and retailing. Some evolution in the theories of concern actually used is observed, along with changes in the efficiency reviews. A statistical model identifies the factors that drive the enforcement process