Abstract: Rule of reason and Per se are two standards used in US law to determine whether a practice or behavior is detrimental to the freedom of trade. Although the same purpose is pursued by using the two principles, the analysis of the practice in question is carried out from different perspectives. This article will compare the two standards in order to highlight the advantages and disadvantages of each.

Keywords: antitrust; anti-competitive practice; market sharing; rule of reason; per se; merger.