The Premerger Notification Rules (HSR Rules or Rules) and the Antitrust Improvements Act Notification and Report Form (HSR Form) were adopted pursuant to section 7A of the Clayton Act. Section 7A requires firms of a certain size contemplating mergers or acquisitions of a specified size to file notification with the Federal Trade Commission (FTC) and the U.S. Department of Justice (DOJ) and to wait a designated period of time before consummating the transaction. It also requires the FTC, with the concurrence of the U.S. Assistant Attorney General for Antitrust, to promulgate rules requiring that notification be in a form and contain information necessary to enable the FTC and DOJ to determine whether the proposed acquisition may, if consummated, violate the antitrust laws. These Rules are continually reviewed in order to improve the program's effectiveness and to reduce the paperwork burden on the business community.

Pursuant to the 2000 Amendments to section 7A of the Clayton Act, codified at 15 U.S.C. 18a, the filing thresholds are revised annually based on the change in gross national product. The threshold reporting figure of the size of transaction test under section 7A(a)(2)(B)(I) is now $75.9 million, which was effective February 24, 2014. 79 FR 3814.

On April 25, 2014, the Commission issued a final rule for the HSR Rules, updating the Instructions to the HSR Form to reflect the address for the Premerger Office's new location in the Constitution Center. The effective date of the new address was May 6, 2014. 79 FR 25662.

The Premerger Office is considering amendments to the HSR Rules regarding standards for the valuation of potentially reportable transactions. The proposed amendments may be issued during the first quarter of 2015. The Premerger Office is also considering amendments to the Instructions to the HSR Form to update information related to NAICS codes, recent rule changes and allow the submission of filings on electronic media.