The most famous United States monopolies, known 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.

While there are still several known near-monopolies in the U.S. and worldwide, some true monopolies, at least in a limited sense, do still exist worldwide.


A History Of U.S. Monopolies

Understanding the Most Famous Monopolies


Government regulation of the American monopolies was initially absent. However, the creation of antitrust regulation in the United States, in the form of the 1890 Sherman Antitrust Act, led to the dismantling and restructuring of Standard Oil and American Tobacco by 1911, as it took several years for their cases to navigate through the court system.

Key Takeaways

  • Until around 100 years ago, a single large company could completely control some major U.S. industries, like steel and oil. 
  • Passage of the Sherman Antitrust Act in 1890 eventually saw major U.S. monopolies break up.
  • A type of limited monopoly that still exists worldwide can be found in the form of nationalized major assets.

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 for many years. In 2018, U.S. Steel was the 26th largest producer of steel in the world, according to the World Steel Association.

More Modern Times

A more recent 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.


A good example of a near-monopoly from very recent history is the De Beers Group, the best-known diamond mining, production, and retail company in the world. De Beers was close to a true monopoly for almost a century, but due to a variety of market and regulatory factors, it has seen its market share go from over 80% in the late 1980s to around 35% as of the end of 2018.

While several U.S. companies in sectors like technology, consumer products, and food and beverage manufacturing have been accused of being monopolies in the media and some in courts, they have rarely been proven so.


The most monopolies that exist today do not necessarily dominate an entire global industry. Rather, they control major assets in one country or region. This process is called nationalization, which occurs most often in the energy, transportation, and banking sectors.

The largest such example of a nationalized major asset is Saudi Arabia's Saudi Aramco, that nation's state-owned oil and natural gas company. It is the single most valuable company in the world at $1.7 trillion as of its late 2019 valuation.