The US term for policies designed to restrict monopoly and promote competition. The Antitrust Division of the US Department of Justice and the Federal Trade Commission are the main agencies for antitrust policy. The name comes from the US use of trusts to describe large firms formed by amalgamation. US antitrust measures frequently work by making practices such as price discrimination illegal. The very name embodies an anti-monopoly position. This can be contrasted with UK terminology, where the Monopolies and Mergers Commission, now the Competition and Markets Authority, was given discretion to judge whether any particular monopoly or merger was harmful. See also monopoly policy.