This is always probable by agency theory that managers of the corporation do not decide based on shareholders' profit, so they tried to prepare a base of opaque reporting and absolutely the crash of the price of stock in order to receive good news in the future. As opposed to that, institutional actionaries are being used by contexts of corporate govermance by emphasizing on them as controlling equips to contrast with opportunistic gravitation and coalesence of efficient contract, to emphasize on the role of institutional investors in guidance machanism of corporation and their potential ability in affecting on methods and politics which are being used by managers. As a result, it is necessary to study about the role of institutional investors in sudden crash of the stock price. Therefore, this research has checked the relation between institutional investors and crash of stock price by exploiting two hypotheses of efficient supervision and revenue convergence and also categorizing institutional investors into two groups of transient and dedicated institutional investors, it has also used the information of 152 accepted companies in Tehran stock market. Findings of the research show that there is a negative and meaningful relation between dedicated institutional investors and crash of stock price. So, there is no relationship between transient institutional investors and the crash of stock price; this matter is pointing to differentiation of transient and dedicated institutional investors and also emphasizing on dedicated institutional investors as efficient controlling equips on pillar of leading the organization and contrast with sudden crash of stock price.

In the context of the Iranian financial market, and with problems such as fragile bubbles in the stock market, the likelihood of stocks crashing, and in particular the severe information asymmetry that exists among investors, most investors are reluctant to take risks and prefer to focus on short-term profitability. This allows many managers to take a myopic approach in investment decisions to increase the firm's short-term profitability. The purpose of this study is to investigate the impact of institutional investors investment horizons including long and short term investment horizons on managerial myopia of the firms listed on the Tehran Stock Exchange (TSE). The research hypotheses wree tested using a sample of 63 companies listed in Tehran Stock Exchange during the year's 2014 to 2018 using Logistic regression model. The results show that according to the first hypothesis test, long-term institutional investors' investment horizons have a significant negative association with the managerial myopia. Also, based on the result of the second hypothesis, we find that short-term investment horizons have a positive and significant association the managerial myopia

One of the literature accounting and financial management, corporate governance, because it is believed that the mechanism of corporate governance receiver capabilities are used That have a direct impact on the ability of investors to force management to efficient use of existing resources in organizations are. The main role of financial reporting, effective in delivering information to people outside the organization credible and timely manner. Managers can use their knowledge about the company's business activities to improve the effectiveness of financial faces, as a means of conveying information to investors and potential creditors, use one of the modes of transmission of information, disclosure of which would be financed through faces. In this study, the relationship between ownership concentration and the percentage of institutional ownership has been dealt with voluntary disclosure data on the five-year period between the years 1389-1393 the firms listed in the Tehran Stock Exchange has been extracted. In order to analyze and test data, statistical software was used Excel and Eviews. The results of tests indicate that the concentration of ownership and the percentage of institutional ownership have a significant relationship with the voluntary disclosure.

Investment institutions with substantial shareholdings in a firm have the resources and incentives to monitor and influence management decisions. Whether the institutions actually monitor and exert pressure on managers is an empirical question. This study is designed to provide insights into the monitoring role of institutional investors by examining whether institutional ownership affects the in formativeness of reported earnings. In this study, different hypothesis (active Monitoring Hypothesis & private benefits Hypothesis) in relation to institutional investors, are tested. Two multifold linear regressions analysis is used to test the relation between corporate Earnings in formativeness and institutional ownership. The results demonstrate significant evidence of a positive association between percent of institutional stock ownership and Earnings in formativeness and approve Effective Monitoring Hypothesis. In addition, the number of institutional ownership dose not improves Earnings in formativeness and decreases it.

This study is designed to provide insights into the monitoring role of institutional investors by examining whether institutional ownership affects the corporate value. Prior studies examining the relation between the shareholdings by institutional investors and corporate value have produced mixed results. In this study, different hypothesis (Effective Monitoring Hypothesis & Convergence of Interest Hypothesis) in relation to institutional investors, are tested. A multifold linear regression analysis is used to test the relation between corporate value and institutional ownership. The results demonstrate significant evidence of a positive association between institutional ownership and corporate value and approve Effective Monitoring Hypothesis. In addition, this study does not find significant linear relationship between concentrated institutional ownership and corporate value and Convergence of Interest Hypothesis is not approved.

In this paper following Lakonishok (1992) and Sias (2004), we examine the presence of herding behavior among active institutional investors, test the presence of momentum strategy (as a determiner of herding behavior) and the correlation between herding behavior and weekly, monthly and quarterly stock return, using time series data of (2006 – 2008) in the Tehran Stock Exchange. Our findings confirm the presence of herding behavior among the institutional investors and show that its intensity is higher than the developed countries, but they reject the presence of momentum strategy and its role as a determiner of herding behavior. Furthermore, the results show that the herding behavior of institutional investors does not affect the market return and has no correlation with the past and future returns.

Stock Return and the factors that affect on it are the discussable subjects in financial research. Institutional Investors as a group of investors, who access to huge financial resources, have an important role in economic and capital market development. On this basis, study about institutional investor's role in stock returns is considered necessary. This paper tended to find evidence in respect of relationship between institutional investors and stock return.. This study is descriptive-correlation based on cross sectional data. 110 firms listed on Tehran stock exchange have selected as samples in 2009. To examine this relationship, multivariable linear regression model was applied. The findings show that there is a significant relationship between institutional investors ownership and stock returns and the presence of institutional investors in firm increases the monitoring on managers' performance and this result in reduction of information asymmetry problems. Ultimately these findings are useful for capital market policy makers to arrange rules in order to institutional investors' establishment and their strengthening in financial environment, and also investors could apply these results to assess risk in their portfolios.

this study investigates stock selection ability between institutional and individual investors. Methodology in this study is based on the intuitive idea that if institutional investors are better at selecting stocks than individual investors, then institutional investors are more likely to buy future winners and sell future losers. while controlling for other factors, such as size and momentum effects, the institutional and individual investor daily trading were regressed on future stock performance. The result of the study dose not show any apparent difference in stock selection ability between individuals and institutional investors. Coefficient of independent variable with dependent variable has positive and negative relation but none of them are significant. Thus first Hypothesis as Changes in institutional investor ownership are related with subsequent abnormal returns is rejected. Second Hypothesis Changes in individual investor ownership are negatively correlated with subsequent abnormal returns is rejected too.