United States Department of Justice Antitrust Division in the context of "United States Department of Justice"

In the United States, antitrust law is a collection of mostly federal laws that govern the conduct and organization of businesses in order to promote economic competition and prevent unjustified monopolies. The three main U.S. antitrust statutes are the Sherman Act of 1890, the Clayton Act of 1914, and the Federal Trade Commission Act of 1914. Section 1 of the Sherman Act prohibits price fixing and the operation of cartels, and prohibits other collusive practices that unreasonably restrain trade. Section 2 of the Sherman Act prohibits monopolization. Section 7 of the Clayton Act restricts the mergers and acquisitions of organizations that may substantially lessen competition or tend to create a monopoly. The Robinson–Patman Act, an amendment to the Clayton Act, prohibits price discrimination.

Federal antitrust laws provide for both civil and criminal enforcement. Civil antitrust enforcement occurs through lawsuits filed by the Federal Trade Commission (FTC), the Antitrust Division of the U.S. Department of Justice, and private parties who have been harmed by an antitrust violation. Criminal antitrust enforcement is done only by the Justice Department's Antitrust Division. Additionally, U.S. state governments may also enforce their own antitrust laws, which mostly mirror federal antitrust laws, regarding commerce occurring solely within their own state's borders.

The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by AT&T, that dominated the telephone services industry in North America for over 100 years from its creation in 1877 until its antitrust breakup in 1983. The system of companies was often colloquially called Ma Bell (as in "Mother Bell"), as it held a vertical monopoly over telecommunication products and services in most areas of the United States and Canada. At the time of the breakup of the Bell System in the early 1980s, it had assets of $150 billion (equivalent to $450 billion in 2024) and employed over one million people.

Beginning in the 1910s, American antitrust regulators had been observing and accusing the Bell System of abusing its monopoly power, and had brought legal action multiple times over the decades. In 1974 the Antitrust Division of the U.S. Department of Justice brought a lawsuit against Bell claiming violations of the Sherman Act. In 1982, anticipating that it could not win, AT&T agreed to a Justice Department-mandated consent decree that settled the lawsuit and ordered it to break itself up into seven "Regional Bell Operating Companies" (known as "The Baby Bells"). This ended the existence of the conglomerate in 1984.

The Federal Trade Commission (FTC) is an independent agency of the United States government whose principal mission is the enforcement of civil (non-criminal) antitrust law and the promotion of consumer protection. It shares jurisdiction over federal civil antitrust law enforcement with the Antitrust Division of the U.S. Department of Justice. The FTC is headquartered in the Federal Trade Commission Building in Washington, DC.

The FTC was established in 1914 by the Federal Trade Commission Act, which the U.S. Congress passed in response to the 19th-century monopolistic trust crisis. Since its inception, the FTC has enforced the provisions of the Clayton Act, a key U.S. antitrust statute, as well as the provisions of the FTC Act, 15 U.S.C. § 41 et seq. Over time, the FTC has been delegated with the enforcement of additional business regulation statutes and has promulgated a number of regulations (codified in Title 16 of the Code of Federal Regulations). The broad statutory authority granted to the FTC provides it with more surveillance and monitoring abilities than it actually uses.