467 U.S. 752 (1984), Supreme Court of the United States
Copperweld Corp. v.
Can a parent corporation and its wholly owned subsidiary conspire with each other within the meaning of §1 of the Sherman Act?
Concerted action under §1 of the Sherman Act requires an agreement among separate economic actors pursuing separate interests such that the agreement deprives the marketplace of independent centers of decisionmaking. A parent corporation and its wholly owned subsidiary have a complete unity of interest and function as a single economic enterprise; their coordinated conduct is deemed unilateral action and is not actionable as a §1 conspiracy. Such conduct remains subject to antitrust scrutiny, when appropriate, under other provisions such as §2 of the Sherman Act and §7 of the Clayton Act.
No. A parent corporation and its wholly owned subsidiary are legally incapable of conspiring with each other under §1 of the Sherman Act because they constitute a single economic entity.
Copperweld is a cornerstone of modern antitrust doctrine distinguishing unilateral conduct from concerted action. It eliminates §1 conspiracy exposure for coordination between a parent and its wholly owned subsidiary, simplifying corporate planning and litigation risk assessment. At the same time, it preserves robust antitrust oversight through §2 and merger enforcement. For law students, the case clarifies how to analyze alleged conspiracies within corporate families, how to frame claims post-Copperweld, and how to apply the single-entity concept in later cases, including American Needle's more nuanced treatment of joint ventures and partially owned affiliates. It is frequently examined to test understanding of the difference between §1 concerted action and §2 unilateral conduct, and how economic substance can prevail over formal corporate structure.