Sherman Act Section 1

Introduction

Section 1 of the Sherman Antitrust Act, 15 USC § 1, prohibits “[e]very contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several States.” Enacted in 1890 as part of the first federal antitrust statute, Section 1 targets concerted action—agreements between two or more persons—that unreasonably restrains competition. The interpretation of Section 1 has evolved significantly over the past century, with courts developing analytical frameworks that distinguish between per se unlawful restraints and those subject to the rule of reason.

The Agreement Requirement

Section 1 applies only to concerted action, not unilateral conduct. A plaintiff must prove the existence of an agreement—a meeting of the minds—between two or more independent actors. The agreement may be proven through direct evidence, such as a written contract or recorded conversation, or through circumstantial evidence, including parallel conduct plus plus factors that suggest coordinated rather than independent action.

The Supreme Court held in Bell Atlantic Corp. v. Twombly (2007) that parallel conduct alone is insufficient to state a Section 1 claim; plaintiffs must allege enough factual matter to suggest that the alleged conspirators entered into an agreement. Conscious parallelism—where competitors independently adopt similar business practices—does not violate Section 1 without evidence of actual coordination. Intracorporate communications between employees of a single entity do not constitute agreement, as a firm cannot conspire with itself.

Per Se Analysis

Certain agreements are considered so inherently anticompetitive that they are condemned as per se violations of Section 1 without any inquiry into their actual competitive effects. Horizontal price fixing, bid rigging, market allocation among competitors, and certain group boycotts are classic per se offenses. The rationale for per se treatment is that these agreements almost always harm competition and have no legitimate economic justification.

The Supreme Court has narrowed the scope of per se analysis over time. In Leegin Creative Leather Products v. PSKS, Inc. (2007), the Court overruled the per se prohibition on resale price maintenance, holding that vertical price restraints should be analyzed under the rule of reason. Similarly, in State Oil Co. v. Khan (1997), the Court overruled the per se rule against maximum resale price fixing. The trend reflects a recognition that economic learning has revealed potential procompetitive justifications for agreements once thought to be universally harmful.

The Rule of Reason

Most agreements are evaluated under the rule of reason, which requires a comprehensive analysis of the agreement’s competitive effects. Under the rule of reason, the plaintiff bears the initial burden of proving that the agreement has anticompetitive effects in a relevant market. If the plaintiff meets this burden, the defendant may offer procompetitive justifications, and the court balances the anticompetitive harms against any procompetitive benefits.

The rule of reason inquiry is highly fact-intensive, requiring courts to examine market structure, the nature of the restraint, and actual market effects. In NCAA v. Board of Regents (1984), the Supreme Court applied the rule of reason to invalidate NCAA restrictions on college football television broadcasts, holding that the limitations on output constituted a naked restraint on competition. The Court rejected the NCAA’s procompetitive justifications, finding that the restrictions were not necessary to preserve the competitiveness of college football.

Horizontal Restraints

Horizontal restraints —agreements among actual or potential competitors—are the most serious Section 1 concerns. In addition to per se unlawful agreements, horizontal agreements may be evaluated under the rule of reason or an intermediate quick look analysis. Quick look applies when an observer with even a rudimentary understanding of economics could conclude that the agreement has anticompetitive effects, without requiring a full market analysis.

California Dental Association v. FTC (1999) illustrates the quick look approach. The Supreme Court held that the CDA’s restrictions on member advertising were subject to more than a quick look but less than a full rule of reason analysis, given the particular characteristics of professional services markets. The Court emphasized that the analytical framework must be flexible and adapted to the circumstances of each case.

Vertical Restraints

Vertical restraints —agreements between firms at different levels of the distribution chain—are generally analyzed under the rule of reason. Non-price vertical restraints, including exclusive dealing, territorial restrictions, and customer allocation, may have both anticompetitive and procompetitive effects. Vertical restraints can promote interbrand competition by encouraging dealers to invest in promotional services, but they can also facilitate collusion or foreclose competitors from distribution channels.

In Continental T.V., Inc. v. GTE Sylvania Inc. (1977), the Supreme Court overruled United States v. Arnold, Schwinn & Co. and held that non-price vertical restraints are subject to the rule of reason. The Court recognized that vertical restrictions may enhance competition by enabling manufacturers to achieve efficiencies in distribution, even though they limit intrabrand competition. Sylvania remains the governing framework for analyzing non-price vertical restraints.

Conclusion

Sherman Act Section 1 prohibits agreements that unreasonably restrain trade. The distinction between per se and rule of reason analysis reflects a century of experience with antitrust enforcement, and courts continue to refine the analytical framework. The requirement of concerted action, the evolving boundaries of per se treatment, and the flexibility of the rule of reason ensure that Section 1 reaches anticompetitive agreements without deterring procompetitive collaboration.