In 1900 Andrew Carnegie was getting old and wanted to sell his Carnegie Steel Company. He turned to the financier J. P. Morgan, a man accustomed to transactions on the largest scale. Paying Carnegie $480 million, Morgan merged his company with steel holdings of his own. In 1901 he announced the result: U.S. Steel, the world’s first billion-dollar corporation.

Inevitably, it faced a challenge under the Sherman Antitrust Act, and the government’s suit against the company reached the U.S. Supreme Court in 1917. In 1920 the justices ruled in favor of the corporation. They determined that it had not engaged in unfair business practices, and was not to be punished merely because of its size.

Morgan had died in 1913, but with this posthumous victory, he completed the work that John D. Rockefeller had begun. Unlike Standard Oil, U.S. Steel showed that it could be both large and legal. Other industries took note, and an era of trustbusting came to an end.

—T.A.H.