The Federal Trade Commission and U.S. Department of Justice (Agencies) deserve credit for deciding to issue for public comment the draft Horizontal Merger Guidelines. The Draft Guidelines take important steps towards better communicating the Agencies’ approach to merger enforcement, not least because the exposition often is more accessible and the discussion of some subtle points has been elaborated. Substantively, the Draft more accurately reflects the Agencies’ actual practice. The Draft also represents an improvement in that it follows the 2006 Commentary on the Horizontal Merger Guidelines in recognizing the usefulness of careful empirical analysis of evidence on key issues in the analysis of likely effects of a merger, including the extent of direct competition among merging firms, the effects of past entry, exit, and merger events, and the experience of firms in achieving forecast efficiencies. Having acknowledged the significant advances made in the Draft, we are concerned that, in several places, the Draft might be construed to signal an overly aggressive approach to enforcement rather than clarifying existing practice. This could have the unfortunate effect of deterring efficient mergers. We identify some examples in the remainder of these Comments.