There is no universally accepted definition of "dominance" for competition policy. The following are some approximations on how this topic has been defined:
- In the United States it has been largely left to courts to decide what constitutes dominance and, for the most part, they have applied criteria based solely on market shares
- The European Commission considers several additional factors such as the overall firm size, whether any essential facility is involved, whether the firm has technological advantages or privileged access to financial resources, the strength of the countervailing power of consumers, and several structural features including economies of scale and scope, barriers to entry, product differentiation, absence of potential competition, and the type and availability of sales channels
- The World Trade Organization defines dominance as a position of economic strength enjoyed by an undertaking which enables it to prevent effective competition being maintained in the relevant market by affording it the power to behave to an appreciable extent independently of its competitors, its providers, its customers and ultimately of the consumers.