Mr. Justice Stone
delivered the opinion of the Court.
By bill in equity filed March 5, 1923, the United States asked an injunction restraining the defendants, who are appellants here, from violating § 1 of the Act of Congress of July 2, 1890, entitled, “An Act to Protect Trade and Commerce Against Unlawful Restraints and Monopolies ” (c. 647, 26 Stat, 209), commonly known as the Sherman Act.
The defendants are the Maple Flooring Manufacturers Association, an unincorporated “trade association”; twenty-two corporate defendants, members of the Association, engaged in the business of selling and .shipping maple, beech and birch flooring in interstate commerce,, all but two of them having their, principal places of business in Michigan, Minnesota or Wisconsin (one"defendant being located in Illinois and one in New York); the several individual representatives of the corporate members of the Association; and George W. Keehn, Secretary of the Association. Of the corporate defendants, approximately one-half own timber lands and saw- mills and are producers of the rough lumber from which they manufacture finished flooring, sold and shipped in interstate commerce. The other defendants purchase rough flooring lumber in the open market and manufacture it. into finished flooring which is sold and shipped in interstate commerce. In 1922 there were in the States of Illinois, Michigan, Minnesota and Wisconsin seventeen nonmember manufacturers of maple, beech and birch flooring and there were fifty-eight non-member manufacturers of maple, beech and birch flooring in the United States who reported to the Government. In that yedr thirty-eight non-member manufacturers reported a manufacturing capacity of 238,616,000 feet of flooring of the types mentioned and during the same-year the manufacturing capacity of the defendants was 158,400,000 feet. Estimates