study the relationship between company’s corporate governance and their performance

the porpose of this research is to investigate the effect of companies corporate governance structure on their performance. in this research, the relationship between two internal mechanisms and four external mechanisms and performance of companies accepted in tehran stock market was examined. performance evaluation criterion is the variable "economic value-added". percentage of nonexecutive managers of board of directors, ownership percentage of members of board of directors, authority concentration and presence of internal auditor were examined as internal mechanisms and audit institute size and ownership percentage of institutional investors as external mechanisms. 98 companies were studied in this research during 2003-2007. research hypotheses were examined temporary and compound data methods. research findings reveal that there is a positive and significant relationship between the proportion of non-executive managers of board of directors and company performance. also, findings show that there is no significant relationship between ownership percentage of institutional investors, ownership percentage of members of board of directors, existence of an internal auditor, size of audit institute and authority concentration and company performance.