384 U.S. 563 (1966)
United States v. Grinnell Corp.
Is Grinnell Corporation liable for monopolization under Section 2 of the Sherman Act based on its control over the alarm service market?
The standard for assessing monopolization under Section 2 of the Sherman Act requires proof of: 1) possession of monopoly power in the relevant market, and 2) the deliberate use of that power to exclude competition or control prices, rather than through growth supported by a superior product, business efficiency, or historic accident.
The Supreme Court held that Grinnell Corporation had monopoly power in the relevant market and had willfully maintained that power through exclusionary practices, thus violating Section 2 of the Sherman Act.
United States v. Grinnell Corp. is a foundational case clarifying the standards for monopolization under the Sherman Act. It articulated a precise legal threshold for what constitutes monopoly power and what actions are considered to maintain it unduly. This case is essential for law students as it underscores the legal limits of competitive behavior and helps to delineate permissible versus impermissible business strategies under antitrust laws. The decision serves as a guiding precedent in evaluating the market conduct of large corporations, especially in evolving industries such as technology and telecommunications.