سید حسین میرجلیلی

Financial Sector includes financial institutions, financial instruments, financial markets, regulations over the financial sector, and policy-making organizations in the financial sector. Financial institutions that collect deposits of the public are consist of governmental(governmental and developmental) and private banks, non-banking financial institutions, credit unions, and Gharz-ul-Hassanah Funds. Commercial insurance companies, social insurances, pension funds are contractual financial intermediaries within the Iranian economy. Investment companies that invest in securities act as investment financial institutions. In the money market, there exist banks, non-banking financial institutions, credit unions, and Gharz-ul-Hasanah Funds. The most important capital market institution in Iran is the Tehran Stock Exchange and there is no derivatives market. Financial instruments within the financial sector of the Iranian economy are stocks, Participation certificates of advantageous projects, and short term and long term deposits in banks. The major regulations over the financial sector in Iran are the law for interest-free banking operation, monetary and banking law, establishment law for securities exchange and the law for issuance methods of participation certificates, and the establishment law for central insurance of Iran and insurer. Some of the challenges within the financial sector of Iran are as follows: Bank-base-system of the financial sector, government's intervention in profit rate assignment and provision of compulsory facilities, lack of presence of private sector within the derivative market, taking effects of monetary policy from fiscal policies and the non-diversified securities within the capital market.

The ultimate goal of investments in stock markets is to earn a satisfactory return on investment, but this is difficult to achieve without enough information to predict stock returns. Information asymmetry refers to a situation where some investors have access to private information that is not reflected in the prices and is yet to be revealed to others. Information asymmetry as a market failure can lead to adverse effects such as poor investor decisions, increased corporate investment risk, and finally reduced stock returns. The issue is important in capital market of developing countries particularly due to the incomplete voluntary disclosure of information as well as its low quality and defective regulatory system. Therefore, in this study, effect of information asymmetry on stock returns has been investigated in a select group of companies listed in Tehran Stock Exchange. The analysis of this relationship was conducted dynamically for the short-term and long-term using Westerlund and Dumitrescu-Hurlin tests and Generalized Method of Moments to achieve articulated results. Using the tests is suitable with cross-sectional dependence of variables and error terms. Also, using the method is appropriate for measuring lagged effect of dependent variable and removing the bias caused by the endogeneity of explanatory variables. The Results demonstrate a significant relationship between information asymmetry and stock return dynamically in short- and long-run. The results show that there is a negative systemic effect of information asymmetry on stock return. Also, debt to asset, profit to sales, firm size and lagged stock return effects are significant.