THE STUDY ROLE OF COMMERCIAL COMPETITION IN THE MARKET ON INTEREST MANAGEMENT OF ACCEPTED COMPANIES IN TEHRAN STOCK EXCHANGE

The purpose of this article is to study the relation between competition in product market and interest management of accepted company on the Tehran Stock Exchange. For this purpose, the index of Herfindahl - Hirschman, Lerner and adjusted Lerner as criteria for measuring product market competition is used. Optional accrual items were used as a measure of interest management. 145 accepted companies in Tehran Stock Exchange comprised statistical population that studied over the years 2010 to 2014. Multivariate linear regression analysis was used to test proposal hypotheses. The results of tests showed that generally there is a significant inverse relation between Herfindahl- Hirschman index, Lerner and adjusted Lerner with interest management of companies.