E. I. du Pont De Nemours and Company (du Pont) (defendant) was a leading manufacturer of chemicals and various related products. In 1917, du Pont purchased a stock interest of 23 percent in General Motors Corporation (GM), one of the leading manufacturers of automobiles. After the stock purchase, du Pont became the primary supplier of automobile finishes and fabrics to GM. In the years after the stock acquisition, GM grew into the nation’s largest automobile manufacturer, eventually accounting for nearly half of all automobile sales. As GM sales grew, so did GM’s need for automobile finishes and fabrics, leading to a corresponding increase in du Pont’s share in the market for automotive finishes and fabrics. Eventually, the United States (plaintiff) brought a complaint against du Pont, claiming that the 1917 stock acquisition violated § 7 of the Clayton Act as a trade restraint likely to substantially reduce competition in the market for automobile finishes and fabrics. The district court held in favor of du Pont, and the government appealed.