Ds are manufacturers and vendors of cast-iron pipe who entered into a combination to raise the prices for pipe for all the states west and south of New York, Pennsylvania, and Virginia, constituting considerably more than three-quarters of the territory of the United States, and significantly called by the associates 'pay territory.' Their joint annual output was 220,000 tons. The total capacity of all the other cast-iron pipe manufacturers in the pay territory was 170,500 tons. Ds made an agreement to fix the pricing of pipe. Their aggregate demand did not exceed 30% of the market share. P sued claiming such an agreement was violative of the Sherman Act. D claimed that the agreement was valid under the common law and also that they still had significant competition in the marketplace. D claimed that its members lacked the power of a monopoly to absolutely fix prices and claimed that the price was fair and competition in the marketplace was not affected. The lower court agreed with D and dismissed P’s complaint. P appealed.