During the Gilded Age, several companies operated as monopolies, dominating their respective industries. The most notable monopolies were:
- Standard Oil Company, founded by John D. Rockefeller, which controlled about 90% of American oil refineries by using horizontal integration to buy out competitors and establish dominance in the oil industry.
- Carnegie Steel, led by Andrew Carnegie, which was a monopoly in the steel industry, controlling most of the steel production.
- U.S. Steel, formed by J.P. Morgan through merging major steel firms, was the world's largest steel company at the time and held a substantial market share.
- American Tobacco, created through the merger of major tobacco firms, becoming a monopoly in the tobacco industry.
These monopolies had vast economic influence, often eliminating competition and controlling prices. Their dominance led to government responses such as the Sherman Antitrust Act of 1890 to curb monopolistic practices.
Thus, among these, Standard Oil and Carnegie Steel are particularly highlighted as classic examples of monopolies during the Gilded Age.
