Chicago Board of Trade v. United States
United States Supreme Court
246 U.S. 231 (1918)
The Chicago Board of Trade (defendant) adopted a rule prohibiting members from trading to-arrive grain at prices other than the closing price until the exchange reopened the next day, a rule the Board argued was adopted to break up a small group of traders' after-hours monopoly on to-arrive grain pricing; the Department of Justice (plaintiff) sued under Section 1 of the Sherman Act, and the district court granted an injunction finding the rule an unlawful restraint of trade, prompting the Board's appeal.
Whether a trade-restraining rule adopted by a commodities exchange automatically violates antitrust law simply because it restrains trade in some respect, without regard to the rule's actual competitive effects.