A firm acting alone—that is, unilaterally—can also harm competition. If it has sufficient influence on a market, it can exclude rivals or limit their capacity to compete. Competition law regimes typically contain provisions prohibiting such conduct. Most use the concept of abuse of dominance to identify and combat it, but a few, including the US, use the term “monopolization” for this purpose. This component of competition law is often controversial and politically sensitive, and globalization increases this tension. This chapter identifies the issues in applying competition law to single firm conduct and reveals how regimes decide whether to pursue it. A single firm can harm competition only if it has sufficient power to influence a particular market, so the chapter looks at how regimes assess this power, how they define the relevant market, and which kinds of conduct constitute a competition law violation. Although most competition laws target this type of conduct, variations in actual treatment are great. The Guide outlines the global patterns and the factors that lead to them.
The Legal Periphery of Dominant Firm Conduct