What Is a Duopoly?

A duopoly is a situation where two companies together own all, or nearly all, of the market for a given product or service. A duopoly is the most basic form of oligopoly, a market dominated by a small number of companies. A duopoly can have the same impact on the market as a monopoly if the two players collude on prices or output.

Understanding a Duopoly

In a duopoly, two competing businesses control the majority of the market sector for a particular product or service they provide. A business can be part of a duopoly even if it provides other services that do not fall into the market sector in question. For example, Google and Meta (formerly Facebook) have dominated digital advertising for much of the 21st century, and function as a duopoly in that field. But Google is not associated with a duopoly in its other product sectors, such as computer software.

A duopoly is a form of oligopoly and should not be confused with a monopoly, where only a single producer exists and controls the market. With a duopoly, each company will tend to compete against the other, keeping prices lower and benefiting consumers. However, since there are only two major players in an industry under a duopoly, there is some likelihood that a monopoly could be formed, either through collusion between the two companies or if one goes out of business.

Oligopoly

A duopoly is a particular type of oligopoly, An oligopoly exists when a few businesses control the vast majority of the market sector. While a duopoly qualifies as an oligopoly, not all oligopolies are duopolies. For example, the automobile industry is an oligopoly because there are a limited number of producers, but more than two, who must respond to worldwide demand.

Duopoly vs. Duopsony

A duopoly should not be confused with a duopsony. In a duopoly, two competing businesses control the majority of the market sector for a particular product or service they provide. For example, Coca-Cola and Pepsi represent a duopoly because the two firms control almost the entire market for cola beverages.

A duopsony, however, is an economic condition whereby there are only two large buyers for a specific product or service. The buyers thus have considerable bargaining power and can determine market demand as long as there are plenty of firms vying to sell to them.

Intel Corp. (INTC) and Advanced Micro Devices Inc. (AMD) are an example of a duopsony. Combined, they command nearly 100% of sales in the computer processing chip market and have substantial influence over their suppliers. Duopsony is also known as a "buyer's duopoly" and is related to oligopsony, a term describing a market where there are a limited number of buyers.

Advantages and Disadvantages of a Duopoly

Duopolies can have both positive and negative effects on the companies in the duopoly and the consumer. First, the two companies can cooperate with each other and maximize their profits as there are no other competitors. In other words, there is a collusive cooperative equilibrium. The companies in a duopoly can concentrate on improving their existing products rather than feeling pressure to create new products for the market. Because the two companies compete with each other, the consumer benefits because prices are controlled to some extent and do not become monopoly prices. The disadvantages of duopolies are that they limit free trade. With a duopoly, the supply of goods and services lacks diversity, and there are limited options for consumers. Also, it is difficult for other competitors to enter the industry and gain market share. The absence of competitors in a duopoly stifles innovation. With a duopoly, prices may be higher for consumers when the competition is not driving prices down.

Price fixing and collusion can occur in duopolies, which means consumers pay more and have fewer alternatives.

Examples of Duopoly

Boeing and Airbus have been considered a duopoly for their command of the large passenger airplane manufacturing market. Similarly, Apple and Samsung dominate the smartphone market. While there are other companies in the business of producing passenger planes and smartphones, the market share is highly concentrated between the two businesses identified in the duopoly.

Visa (V) and Mastercard (MA) are considered a duopoly. The two financial powerhouses own over 80% of all European Union card transactions. This dominance has led the European Central Bank (ECB) to try to find ways to break up the duopoly. So far, the ECB has tried interchange fee caps, but a new scheme that would allow instant payments using national payment cards across European countries could be a game-changer.

A European infrastructure for instant payments would eliminate the need for people to use the global services of Visa or Mastercard. Another suggestion is to allow instant payments at points of interaction or points of sale so that the need for the traditional cards would disappear altogether.

The Bottom Line

There are plenty of examples of duopolies in today's markets—Coca-Cola and Pepsi in the soda industry and Apple and Samsung in the smartphone industry are two of them.

Duopolies are a form of oligopoly, and the biggest disadvantage of duopolies, oligopolies, and monopolies is that the companies involved can dominate markets, collude with each other, and raise prices for the consumer.