Monopoly type of market and that of Oligopoly type of market

Monopolistic Competition

Monopolistic competition also refers to a market structure, where a large number of small firms compete against each other. However, unlike in perfect competition, the firms in monopolistic competition sell similar, but slightly differentiated products. This gives them a certain degree of market power which allows them to charge higher prices within a certain range.

Monopolistic competition builds on the following assumptions: (1) all firms maximize profits (2) there is free entry and exit to the market, (3) firms sell differentiated products (4) consumers may prefer one product over the other. Now, those assumptions are a bit closer to reality than the ones we looked at in perfect competition. However, this market structure will no longer result in a socially optimal level of output, because the firms have more power and can influence market prices to a certain degree.

Oligopoly

An oligopoly describes a market structure which is dominated by only a small number firms. This results in a state of limited competition. The firms can either compete against each other or collaborate (see also Cournot vs. Bertrand Competition). By doing so they can use their collective market power to drive up prices and earn more profit.

The oligopolistic market structure builds on the following assumptions: (1) all firms maximize profits, (2) oligopolies can set prices, (3) there are barriers to entry and exit in the market, (4) products may be homogenous or differentiated, and (5) there is only a few firms that dominate the market. Unfortunately, it is not clearly defined what a «few» firms means exactly. As a rule of thumb, we say that an oligopoly typically consists of about 3-5 dominant firms.

To give an example of an oligopoly, let’s look at the market for gaming consoles. This market is dominated by three powerful companies: Microsoft, Sony, and Nintendo. This leaves all of them with a significant amount of market power.