Skip to main content

The Federal Trade Commission today released a staff analysis of horizontal merger investigations for fiscal years 1996 to 2003. The merger data released contains tabulated market share and concentration levels associated with the FTC’s investigations in more than 780 markets over the last eight years. The data tabulations use the two market share concentration statistics described in the agency’s Horizontal Merger Guidelines – the post-merger Herfindahl-Hirschman Index (HHI) and the change in the HHI – and reflect 151 horizontal merger investigations in total.

For a subset of the investigations – those with three or fewer markets – the FTC staff also retrieved information on whether or not “hot documents” or “strong customer complaints” were identified during the investigation. The FTC staff have tabulated the Commission’s enforcement decisions based on the presence or absence of these variables. These results are presented in tabular format. In addition, the data discuss the number of “significant competitors” with regard to decisions to seek relief in horizontal merger investigations, defining the term relative to the competitive effects theory that was the most plausible basis for the specific investigation. Data on “significant competitors” is presented for 573 relevant markets.

The FTC and Antitrust Division of the U.S. Department of Justice also have announced that they will hold a joint workshop on merger enforcement in Washington, DC, on February 17-19, 2004. Copies of the announcement of a workshop on merger enforcement, as well as the summary of merger challenges data for fiscal years 1999-2003, can be found on the Commission’s Web site at

Copies of this press release, the data it describes, and the Commission’s initial set of merger-related data issued on December 18, 2003 can be found on the FTC’s Web site at The FTC’s Bureau of Competition seeks to prevent business practices that restrain competition. The Bureau carries out its mission by investigating alleged law violations and, when appropriate, recommending that the Commission take formal enforcement action. To notify the Bureau concerning particular business practices, call or write the Office of Policy and Evaluation, Room 394, Bureau of Competition, Federal Trade Commission, 600 Pennsylvania Ave, N.W., Washington, D.C. 20580, Electronic Mail:; Telephone (202) 326-3300. For more information on the laws that the Bureau enforces, the Commission has published “Promoting Competition, Protecting Consumers: A Plain English Guide to Antitrust Laws,” which can be accessed at

Contact Information

Media Contact:
Office of Public Affairs