evaluation of market power in manufacturing industries in iran

this paper using generalized roeger's model calculated the lerner index for iranian active industries in 4-digit isic codes during the period 1995-2007. the findings indicate that the lerner index has been between 8 to 16 percent in 38 industries among 131 ones. the index also in different industries shows that more than 50 percent of iranian industries have monopolistic power such that they have generated a significant gap between price and marginal cost. comparing the lerner index with herfindahl–hirschman and four - firm concentration ratio indices gives this result that the industries with high concentration ratio have greater value of lerner index so that the four-firm concentration ratio of 20 industries (among the 29 industries) has had a value more than 40.jel classification: f1 ،l1،l6