The Impact of Corporate Governance Mechanisms on Informational Efficiency of Listed Companies in Tehran Stock Exchange

The purpose this study is examines the impact of corporate governance mechanisms on informational efficiency of listed companies in Tehran Stock Exchange. Among the various mechanisms of corporate governance, determine the four criteria include institutional ownership, Free float, Independent board members and Ownership concentration as the mechanisms of corporate governance and we test their effect on the informational efficiency. In this study, the regression model as research model was used that for calculate of Informational efficiency was used monthly return variance ratio test. The study sample is consisted of 95 companies listed in Tehran Stock Exchange during the years 2008 to 2012. The results of this study indicate that Institutional investors have opposite effect on the Informational efficiency of companies listed in Tehran Stock Exchange. However, other mechanisms of corporate governance used in this study, including the Free float, Independent board members and Ownership concentration on the Informational efficiency in Tehran Stock Exchange have any effect on Informational efficiency