The Federal Trade Commission is amending the premerger notification rules, which require the parties to certain mergers or acquisitions to file reports with the Commission and with the Assistant Attorney General in charge of the Antitrust Division of the Department of Justice and to wait a specified period of time before consummating such transactions, pursuant to section 7A of the Clayton Act. The filing and waiting period requirements enable these enforcement agencies to determine whether a proposed merger or acquisition may violate the antitrust laws if consummated and, when appropriate, to seek a preliminary injunction in federal court to prevent consummation. This rule amendment is necessary to address public comments regarding a previously published interim rule provision, and will increase the clarity and improve the effectiveness of the rule.