The United States v. Trenton Potteries Company et al., 1926, was a significant antitrust case in which the U.S. Supreme Court held that price-fixing agreements are illegal per se under the Sherman Antitrust Act. The defendants, who were manufacturers and distributors of vitreous pottery bathroom fixtures controlling 82% of domestic production, had agreed to fix prices at an artificially high level. They argued that their actions were not unreasonable because they did not possess monopoly power and their prices were fair given the quality of their products. However, the court rejected this argument stating that any agreement or conspiracy to control prices is inherently unlawful regardless of its reasonableness or whether it involves monopolistic practices or not.

In the dissenting opinion for the United States v. Trenton Potteries Company case, Justice Stone argued that price-fixing should not be automatically considered illegal per se under the Sherman Act. He suggested that courts should consider whether such arrangements unreasonably restrain trade on a case-by-case basis, taking into account factors like market conditions and consumer impact. According to him, if prices are set at reasonable levels and competition is not stifled, then these agreements might actually benefit consumers by ensuring product quality and availability. Therefore, he disagreed with the majority's view which held all forms of price fixing as inherently harmful to economic competition without considering its potential benefits or context-specific impacts.