327 U.S. 251 (1946) (U.S. Supreme Court)
Bigelow v. RKO Radio Pictures, Inc.
When a defendant's antitrust conspiracy makes it impossible to measure a plaintiff's lost profits with precision, may a jury award damages based on a just and reasonable estimate derived from methods such as before-and-after and yardstick comparisons, or is such proof impermissibly speculative?
In private antitrust actions under the Clayton Act, once the fact of injury and causation are established, the amount of damages need not be proven with mathematical exactness where the defendant's wrongdoing has made precise computation impossible. The plaintiff may rely on relevant data to permit a just and reasonable estimate of the loss; the wrongdoer bears the risk of uncertainty created by its own misconduct. Only speculation lacking a reasonable evidentiary foundation is impermissible; approximations grounded in credible comparisons (e.g., before-and-after or yardstick methods) are permissible.
Yes. The Supreme Court held that the plaintiffs' damages evidence—using before-and-after and yardstick comparisons—provided a sufficient basis for the jury to make a just and reasonable estimate of antitrust damages. The Court reversed the court of appeals and reinstated the jury's verdict.
Bigelow is a leading authority on proving damages when unlawful conduct clouds the counterfactual world. It entrenches the principle that wrongdoers bear the risk of uncertainty they create and validates pragmatic estimation tools—before-and-after and yardstick methods—that remain standard in antitrust and beyond (e.g., IP infringement, unfair competition, and certain contract cases). The case teaches careful separation of proof of liability (including causation) from the quantum of damages, the latter of which may be approximated if grounded in reliable data. For law students, Bigelow is essential for understanding evidentiary burdens in complex markets, the role of economics in litigation, and the policy rationale behind treble-damages enforcement.