Glossary term

Sherman Antitrust Act of 1890

The Sherman Antitrust Act of 1890 is a foundational U.S. antitrust law prohibiting certain restraints of trade and monopolization.

Updated

May 16, 2026

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2 min read

What Is the Sherman Antitrust Act of 1890?

The Sherman Antitrust Act of 1890 is a foundational U.S. antitrust law. It prohibits certain agreements that restrain trade and conduct that monopolizes, attempts to monopolize, or conspires to monopolize markets.

The law remains central to U.S. competition policy. It works alongside later statutes, including the Federal Trade Commission Act and the Clayton Act.

Key Takeaways

  • The Sherman Act was passed in 1890 and remains a core U.S. antitrust law.
  • Section 1 addresses contracts, combinations, or conspiracies that restrain trade.
  • Section 2 addresses monopolization, attempted monopolization, and conspiracy to monopolize.
  • Some conduct, such as price fixing among competitors, can be treated especially harshly.
  • Antitrust analysis is fact-specific and should not be reduced to company size alone.

How the Sherman Act Works

The Sherman Act targets anticompetitive conduct, not ordinary success. A company can become large by competing well, but it can violate antitrust law if it unlawfully restrains competition or maintains monopoly power through exclusionary conduct.

Enforcement can come from the U.S. Department of Justice, the Federal Trade Commission, state attorneys general, and private plaintiffs. Remedies may include injunctions, damages, penalties, or changes to business practices.

Criminal enforcement is especially associated with hard-core cartel conduct, while many civil cases involve detailed analysis of market power and competitive effects.

Key Sherman Act Concepts

Concept

Meaning

Example concern

Restraint of trade

Agreement that unreasonably limits competition

Price fixing or market allocation

Monopolization

Maintaining monopoly power through improper conduct

Exclusionary practices

Attempt to monopolize

Conduct aimed at gaining monopoly power unlawfully

Predatory or exclusionary behavior

Rule of reason

Fact-specific balancing of competitive effects

Some vertical agreements

Per se treatment

Certain conduct treated as inherently illegal

Hard-core cartel behavior

Why It Matters

The Sherman Act matters because competition affects prices, wages, innovation, quality, and market access. Antitrust law is designed to protect the competitive process, not individual competitors from fair competition.

For businesses, antitrust risk can affect pricing, distribution, mergers, joint ventures, trade association activity, and communications with competitors.

Limits and Misunderstandings

The Sherman Act does not make every monopoly illegal. The legal issue is how market power was obtained or maintained and whether conduct harmed competition.

It also does not automatically prohibit aggressive competition, low prices, or business growth. The facts, market definition, and competitive effects matter.

The Bottom Line

The Sherman Antitrust Act is a cornerstone of U.S. competition law. It targets unlawful restraints of trade and monopolization while leaving room for companies to compete, grow, and win customers lawfully.

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