M.A. Thesis:

Top managerial power and stock price efficiency

The main objective of this research is to determine the impact of corporate governance mechanisms on stock price performance in Tehran Stock Exchange. Consideration of different dimensions of corporate governance and its impact on accounting variables are issues that have been addressed in accounting literature. Corporate governance includes laws, regulations, processes, cultures and systems that achieve the goals of accountability, transparency, justice, and respect for stakeholders' rights. Among the various corporate governance mechanisms, four criteria including corporate focus, duality of the CEO's mission, the independence of the board of directors and institutional ownership have been selected as corporate governance mechanisms and their impact on stock performance has been tested. This research was conducted for a period of 5 years between 91 and 95 years. In this research, the company's time, financial leverage and company size have also been used as a control variable. The sample information of the companies studied after the availability of their information is collected by collecting with the help of the Excel software. With the help of Eviews software. The results of the research showed that there is a positive and significant relationship between the focus on equity and the cost-effectiveness of the transaction. ¬ Ownership concentration in the hands of one or several major shareholders is the mechanism for controlling the company It is considered as having a positive effect on stock price performance. But there is a negative and significant relationship between the CEO's dichotomy and the cost-effectiveness of the transaction, which can be due to the lack of proper separation of the duties of the executive directors (CEO) and the board members. There was also no relationship between the independence of the board of directors and institutional ownership with the performance of stock prices. The reason for the disapproval of the third and fourth hypotheses can also be due to the emergence of corporate governance mechanisms in Iran's capital market and the lack of recognition of the effectiveness of corporate governance criteria.

Keywords: Stock Price Efficiency, Corporate Governance, Ownership Focus, Managing Director Diversity, Independence of the Board of Directors, Institutional Ownership