The Great Northern Railway Company and the Northern Pacific Railway Company were competitors in the markets they served. The two conceived a plan of organizing a corporation, D, which would hold the shares of the stock of the constituent companies to become one powerful consolidated corporation. D was organized as the holding corporation through which that scheme should be executed; and under that scheme, such holding corporation became the holder -- more properly speaking, the custodian -- of more than nine-tenths of the stock of the Northern Pacific, and more than three-fourths of the stock of the Great Northern. P sued alleging that the combination of the two railroads who were active competitors in their regions of operation was a violation of Section 1 of the Sherman Act. The trial court held for P and D appealed.