Competition policy in different global regions can be marked, even with increasingly globalized activities of business firms. There may be major differences in philosophy, policy, or practice. Substantive standards for competition policy are not equivalent in those countries having competition laws. Many areas covered by competition law are subject to a "rule of reason", [ie] many business practices that might hinder competition are neither [per se] legal nor illegal but rather depend upon circumstances and intended outcome. Some differences could lead to economic costs and international friction. For example, Lack of clarity over competition policy makes it difficult for nations either to "harmonize" their competition policies ([ie] to implement common substantive and enforcement standards) or to negotiate common rules at a supranational level. While there is a high degree of consensus on what issues should be covered by competition policy ([eg] cartels, monopoly, vertical arrangements, predatory practices, merger and acquisition regulation, [etc]), there is no consensus on what specific rules should govern these issues. Alternatives for eliminating these costs and frictions include unilateral policy changes, bilateral or multilateral harmonization of policies, and creation of new international regimes to supplement or replace national or regional regimes.
"Best practice" in competition policy has evolved considerably over recent decades, especially in the USA.