The Federal Trade Commission Act bans "unfair methods of competition" and "unfair or deceptive acts or practices." The Act, signed into law by Woodrow Wilson in 1913, outlaws unfair methods of competition and to outlaw unfair acts or practices that affect commerce. The act also creates the Federal Trade Commission, a five-member board, to regulate questionable business practices. The Supreme Court has said that all violations of the Sherman Act also violate the FTC Act. Thus, although the FTC does not technically enforce the Sherman Act, it can bring cases under the FTC Act against the same kinds of activities that violate the Sherman Act. The FTC Act also reaches other practices that harm competition, but that may not fit neatly into categories of conduct formally prohibited by the Sherman Act. Only the FTC brings cases under the FTC Act.
The Clayton Act addresses specific practices that the Sherman Act does not clearly prohibit, such as mergers and interlocking directorates (that is, the same person making business decisions for competing companies). The Sherman Antitrust Act was a part ofUnited States antitrust law with the goal of adding further substance to the U.S. antitrust law regime; the Clayton Act sought to prevent anticompetitive practices in their incipiency. That regime started with the Sherman Antitrust Act of 1890, the first Federal law outlawing practices considered harmful to consumers (monopolies, cartels, and trusts). The Clayton Act specified particular prohibited conduct, the three-level enforcement scheme, the exemptions, and the remedial measures. Section 7 of the Clayton Act prohibits mergers and acquisitions where the effect "may be substantially to lessen competition, or to tend to create a monopoly." As amended by the Robinson-Patman Act of 1936, the Clayton Act also bans certain discriminatory prices, services, and allowances in dealings between merchants. The Clayton Act was amended again in 1976 by the Hart-Scott-Rodino Antitrust Improvements Act to require companies planning large mergers or acquisitions to notify the government of their plans in advance. The Clayton Act also authorizes private parties to sue for triple damages when they have been harmed by conduct that violates either the Sherman or Clayton Act and to obtain a court order prohibiting the anticompetitive practice in the future.
In addition to these federal statutes, most states have antitrust laws that are enforced by state attorneys general or private plaintiffs. Many of these statutes are based on the federal antitrust laws.