Hamid Reza Imany - Department of Accounting,College Of Economic And Management,Shiraz Branch, Islamic Azad University ,Shiraz,Iran Km5, Sadra Road, Shiraz, Iran

The purpose of this research is to study The Relationship Between Product Market Competition and the Cost of Equity Capital in the Companies Listed in Tehran Stock Exchange (TSE). Hence, an attempt will be made to answer the following question: Is there a significant relationship between Product Market Competition and Cost of Equity Capital . To find the answer, this research utilizes the the Herfindahl-Hirschman, Lerner and Modified Lerner indexes as proxies for product market competition. The statistical sample of the study consists of 82 companies of the TSE during 2009 to 2014; E- views are used for testing hypothesis. The results suggest that there is a negetive relationship between criteria of Product Market Competition (i.e. Herfindahl-Hirschman, Lerner and Modified Lerner indexes) and Cost of Equity Capital

Product Market Competiti, Cost of Equity Capital, Herfindahl-Hirschman indexes