The United States Supreme Court case against the National Association of Securities Dealers, Inc. (NASD) in 1974 revolved around allegations that NASD and its members had violated antitrust laws by preventing a new method of selling mutual funds at discounted rates from being implemented. The government argued that this action was an illegal restraint on trade as it prevented competition and maintained high commission rates for brokers. However, NASD contended they were exempt from these laws due to their status as a self-regulatory organization under the Maloney Act. The Supreme Court ruled in favor of the government, stating that while certain activities might be immune from antitrust scrutiny due to regulatory oversight, not all actions taken by such organizations are automatically exempted. They concluded that there was no explicit language in the Maloney Act providing immunity for restraining competitive practices among brokers or dealers.

In the dissenting opinion for United States v. National Association of Securities Dealers, Inc., Justice Powell argued that the majority's decision to uphold a lower court ruling against NASD was based on an overly broad interpretation of antitrust laws. He contended that Congress had intended for self-regulatory organizations like NASD to have some degree of immunity from these laws in order to effectively carry out their regulatory functions. Furthermore, he believed that the specific practices at issue in this case - namely, attempts by NASD members to prevent aggressive price competition among mutual funds - were not necessarily anti-competitive or harmful to consumers. Instead, they could be seen as efforts by industry professionals to maintain high standards and protect investors from risky investment strategies. Therefore, he concluded that these practices should not be automatically deemed illegal under antitrust law without further analysis of their actual impact on market competition and consumer welfare.