As of 2018, two of the most well-known oligopolies in the United States are the film and wireless communications industries. In Canada, the banking and wireless communications industries are oligopolies. Worldwide oligopolies include computer and smartphone operating system developers.

An oligopoly is similar to a monopoly except that the market is controlled by a few firms rather than just one. For example, film production in the U.S. is dominated by six companies, which earned $5.2 billion in profits in 2016:

  • Time/Warner
  • Walt Disney
  • Twenty-First Century Fox
  • NBC/Universal
  • Sony
  • Viacom

As of 2018, four wireless companies—Verizon, AT&T, Sprint and T-Mobile—account for 98% of wireless revenues in the U.S.

Notably, the following seven banks control the Canadian banking industry:

  • The Royal Bank of Canada (RBC)
  • TD Canada Trust
  • Bank of Nova Scotia
  • Bank of Montreal (BMO)
  • Canadian Imperial Bank of Commerce (CIBC)
  • Desjardins Group
  • National Bank of Canada

Bell, Rogers and Telus own over 90% of the Canadian wireless market.

Worldwide, Windows, Mac OS and Linux, control almost the entire computer operating systems market. Meanwhile, just two operating systems, Google Android and Apple iOS, have over 90% of the smartphone and tablet market share.

These are all examples of imperfect or differentiated oligopolies because the products and services these companies offer, while often very similar, are not exactly the same. This is in contrast to a pure or perfect oligopoly, in which competitors produce goods that are virtually identical. There are few truly pure oligopolies, although the steel, cement and aluminum industries are considered to be close.