Abstract
The purpose of this research, examination influence ownership structure on information asymmetry and financial performance. That is, investigate level and procedure impressments institutional investor on financial performance and information asymmetry until determine whether while become stronger monitoring and evaluating incentives, this relation will be invigorate? For test research hypothesis, sample selection involve 60 listed companies on Tehran Stock Exchange that active during years 2005-2009. Result show that significant and negatively relationship between ownership institutional shareholdings and informational asymmetry. That is, whatever institutional ownership level increased presentation information by firm managers to people connected with market too increased. On the other hand, increase institutional ownership lead to decrease information asymmetry that this matter will be inducement efficiency market regarding to information. At this research, also confirmed relationship institutional shareholding ownership with return on equity and likewise have positively related with financial performance. Thus can argue that whatever number institutional shareholding on ownership combination (structure) more, inducement sharing monitoring and control among shareholding that this matter will be lead to reduction conflicts of interest and increase profitability