The most famous monopolies, largely for their historical significance, are Andrew Carnegie’s Steel Company (now U.S. Steel), John D. Rockefeller’s Standard Oil Company, and the American Tobacco Company. From the late 19th to the early 20th century, these organizations maintained singular control over the supply of their respective commodities. Without free market competition, these companies effectively set the national price for steel, oil, and tobacco.
Government regulation was initially absent. However, the creation of antitrust regulation in the United States, in the form of the 1911 Sherman Antitrust Act, led to the dismantling and restructuring of Standard Oil and American Tobacco in the same year. U.S. Steel was challenged but not found to be the sole supplier of steel to the U.S. market, though it continued to possess considerable market share. In 2014, U.S. Steel was the 13th largest producer of steel in the world, according to the World Steel Association.
A more contemporary monopoly to have experienced the same fate as Standard Oil and American Tobacco is the American Telephone and Telegraph Company. In 1982, AT&T was found to be in violation of U.S. antitrust law while acting as the sole supplier of telephone services to the country. As a result, it was forced to split into six subsidiaries, known as Baby Bells.