عنوان مقاله [English]
Similar to national markets, anti-competitive behavior may cause monopoly power in international markets. Firms and countries may use strategic and coordinated measures to distort the market form competition market to monopoly. Concentration is an index that can be used as a proxy for the degree of monopoly or competition. This index contains the information about the numbers of firms and the way market shares are distributed among the firms in any market. The main aim of this paper is to assess the degree of competition in those international markets in which Iranian export items have a prominent place. To evaluate the degree of competition, concentration indices have been used. The estimated concentration indices, HHI and CRn, have shown that the structure of the above mentioned markets are tight oligopoly . During 1977-2000 the extent of HHI and CRn increased in world markets for items such as date, carpet , caviar, raisins, and saffron, which attested to the increasing monopoly power in these markets. On the other hand there was no significant evidence for changing of concentration in world markets for apple and grape.