Examining the Effect of Auditing Institution, Internal Auditing Department and Companies Profitability on Voluntary Information Disclosure in Tehran Stock Exchange

In this study it was attempted to examine the relation between auditing institution, internal auditing department and profitability with the voluntary information disclosure in yearly reports of the companies listed in Tehran stock exchange in consideration of the role played by voluntary disclosure and transparency in retaining shareholders profits and improving capital market efficiency. in line with this aim a sample of the producing companies who had published the fiscal statements and the reports of board of directors in relation to March, 20, 2011 and were listed in Tehran stock exchange was selected and finally 97 ones were selected among them. The study findings indicate that there is a significant and positive relation between auditing department and voluntary information disclosure level and there is negative and significant relation between auditing institution and voluntary disclosure and also there is no significant relation between voluntary disclosure rate and companies profitability.