SummaryThe analysis of market structures is of great importance when studying microeconomics. How the market will behave, depending on the number of buyers or sellers, its dimensions, the existence of entry and exit barriers, etc. will determine how an equilibrium is reached. Even though market structures were thoroughly analysed by economists from the early 20th century on, its study can be traced back to economists such as Antoine Cournot, Alfred Marshall or even Adam Smith.
Oligopsony (from the greek «oligoi», few, and «opsõnía», purchase) is a market structure form of imperfect competition characterized by the existence of a relative small number of buyers, and many sellers. It is a similar case to oligopoly but were the oligopolistic powers come from the demand side. Monopsonies, a term first coined by Joan Robinson in her book “The Economics of Imperfect Competition”, 1933, are a particular case of oligopsonies, where there is only one buyer, which holds all the negotiating power.