United States v. E. C. Knight Co., 156 U.S. 1 (1895), also known as the "Sugar Trust Case," was a United States Supreme Court antitrust case that severely limited the federal government's power to pursue antitrust actions under the Sherman Antitrust Act. In Chief Justice Melville Fuller's majority opinion, the Court held that the US Congress could not regulate manufacturing and thus gave state governments the sole power to take legal action against manufacturing monopolies. The case has never been overruled, but in Swift & Co. v. United States and subsequent cases, the Court has held that Congress can regulate manufacturing when it affects interstate commerce.

The Sherman Antitrust Act of 1890 is a United States antitrust law which prescribes the rule of free competition among those engaged in commerce. It was passed by Congress and is named for Senator John Sherman, its principal author.