In the 1941 case of Board of Trade of Kansas City et al. v. United States et al., the U.S Supreme Court upheld a lower court's decision that certain practices by the Kansas City Board of Trade were in violation of antitrust laws, specifically Section 2(a) and (b) Sherman Act and Section 3 Clayton Act. The board had been accused by grain dealers from other states for fixing prices through its call system, which allowed members to bid on grains before they reached public markets. This practice was deemed as monopolistic because it restricted competition and manipulated market prices unfairly. The court ruled that such activities constituted an unreasonable restraint on trade, thereby violating federal law.

In the dissenting opinion for the Board of Trade of Kansas City et al. v. United States et al., Justice Roberts argued that there was no violation of anti-trust laws by the defendants, as they were merely acting within their rights to protect their business interests. He contended that these businesses had a right to establish rules and regulations governing transactions on their exchange, including setting minimum commission rates for services provided by members. According to him, such practices did not constitute an unreasonable restraint on trade or commerce but rather served as necessary measures in maintaining fair competition and preventing destructive price wars among brokers. He also pointed out that Congress had never intended for anti-trust laws to interfere with self-regulation within industries like this one; thus he believed it was inappropriate for courts to apply them in such cases without clear legislative guidance.