What is Market Concentration
Description: The market concentration ratio measures the combined market share of all the top firms in the industry. ¡®Market Share¡¯ is used as a reference here in the formulae. It could be sales, employment statistics, number of people using a company¡¯s services, number of outlets etc. The value of top firms or top ¡®n¡¯ firms may be three or maximum five. If the top firms keep on gaining market share, then we say that the industry has become highly concentrated. To understand market concentration, let¡¯s first understand ¡®concentration¡¯. Concentration within an industry can be defined as the degree at which a small number of firms make up for the total production in the market. If the concentration is low, it simply means that top ¡®n¡¯ firms are not influencing the market production and the industry is considered to be highly competitive. On the other hand, if the concentration is high, it means that top ¡®n¡¯ firms influence the production or services provided in the market the industry then is said to be oligopolistic or monopolistic.
The most common measure to calculate the market concentration is the Herfindahl-Hirschman Index (HHI). This index is calculated by adding the square root of the percentage market share of each individual firm in the industry. For example in a market consisting of only five firms with shares of 30%, 30%, 20%,20% and 20%, the Herfindahl Index would be 3000 (900 + 900+ 400+ 400+400). The index may rise as high as 10,000 if the market has a monopoly. But, lower the index is, more competitive the market becomes. The indicator could become zero for the perfect competition.