On the heels of the historic proposed changes to the Hart-Scott-Rodino (“HSR”) merger review process, the U.S. Department of Justice Antitrust Division and the Federal Trade Commission released the 2023 Draft Merger Guidelines for public comment. The single set of guidelines will replace the former horizontal and vertical guidelines, becoming the principal resource for merger review and challenges. The DOJ and FTC will finalize the Draft Guidelines following the close of the 60-day comment period on September 18, 2023. Together, the two sets of changes usher in a radically different climate for dealmaking in the U.S. and have the potential to grind transactions to a near halt just as M&A is beginning to regain steam.