Estimation and Comparison of the Concentration Ratio in Iranian Industry Using the Lognormal Model

The Concentration of firms in an industry is of the interest of economists, business, strategist, and government agencies. The concentration ratio is the percent of the market share owned by the largest few firms in an industry. In this research the 5-firm concentration ratio is estimated using the lognormal model by 2002 statistics and its comparison with that of 1994; corresponding to 2-digit ISIC industrial code, in terms of employment. The results indicate that the concentration ratio in all industries except the industry of Radio, Television and Communications have reduced in 2002 relative to that of in 1994. In these years, the Fabric metal (but machineries and instruments) production, Non-metal mineral products, Textiles, Furniture and Other unclassified products have been the most competitive industries, respectively.