Measuring the social costs of monopoly in Iran's industrial sector and determining the factors affecting them

The main purposes of this study are to investigate the social costs of monopoly and to determine the factors affecting them. To measure social costs, three methods of Harberger, Posner and Calling Müller are used, and for this purpose, data from 130 ISIC four-digit code industries during the years 2004 to 2017 were used.To analyze the model, panel data, Generalized Method of moments and Eviews 10 were used. Although in the previous studies, social costs of monopoly in Iran  have been measured,  in this study, the factors affecting them are also evaluated. The research findings show  that the social costs of monopoly in the Posner and Kaling-Muller methods are much higher than in  the Harberger method, which causes disturbance in the optimal allocation of resources and reduces the welfare of society.  Also, the results of the study of factors affecting the social costs of monopoly show that in all three approaches, all variables with a level of probability of 5% are significant and the signs of the variables are in accordance with theoretical expectations. As the variables of concentration index, advertising intensity and research and development intensity are the most important variables affecting social costs and increase them.