Investigating the Relationship between Corporate Governance and the Level of Voluntary Disclosure of the Companies Listed in Tehran Stock Exchange

The meaning of corporate governance represents the governance that applies to a stock company and according to it, how corporate accountability to shareholders and other stakeholders is formed. The level of voluntary disclosure is one type of mechanisms of accountability to stockholders and other beneficiaries. Therefore, the purpose of this research is to study the relationship between corporate governance and the level of voluntary disclosure of the companies listed in Tehran Stock Exchange. Research Hypotheses: According to the theoretical basis and literature, three hypotheses were designed and tested: There is a significant relationship between institutional ownership and the level of voluntary disclosure of the companies listed in Tehran Stock Exchange. There is a significant relationship between the percentage of independent directors in the board director and the level of voluntary disclosure of the companies listed in Tehran Stock Exchange. There is a significant relationship between the chairman and CEO/chair duality and the level of voluntary disclosure of the companies listed in Tehran Stock Exchange. The population of the study consisted of all firms listed in Tehran Stock Exchange. In this research, 71 companies were surveyed during theyears 2003-2011. To determine corporate governance, institutional ownership, the percentage of independent directors in the board director and the chairman and CEO/chair duality have been applied. Moreover, Botosan (1997) check list which has been adjusted by Kashanipour et al. (2009) was utilized to measure the level of voluntary disclosure. The check list consisted of 71 indices through six section of background information, the summery of historical results, key non-financial statistics, segments information, projected information and management discussion and analysis. To test research hypotheses multivariate regression with panel data was utilized. The results showed that when independent directors in the board director increase, the level of voluntary disclosure will increase and CEO/chair duality reduces the level of voluntary disclosure. But, there is no significant relationship between institutional ownership and the level of voluntary disclosure of the companies listed in Tehran Stock Exchange.