The Impact of Profit Changes Speed on Stock Portfolio Fluctuations Companies Accepted in Tehran Stock Exchange

Objective: The capital market is considered due to its essential role in collecting financial resources in various ways such as small and large savings, optimizing the circulation of financial resources and directing them towards the expenses and investment needs in productive economic sectors. Even some economists believe that the difference between developed and underdeveloped economies is not only in advanced technology, but it can be seen in the existence of integrated, active and extensive financial markets. A look at the favorable growth of Iran's capital market under the conditions of sanctions and the spread of the Corona virus, shows that entering this market has been the focus of people's attention and interest.Investors in the capital market seek to achieve and implement strategies that can overcome the challenges in the market. Often, investment decisions are considered in the optimal selection of investors' portfolios based on the relationship between risk and return and the level of profitability, which is a factor of the superiority of a share. As a result, profit changes are not hidden from the eyes of investors, and they react to profit changes, but they do not pay attention to the speed of profit changes, which can lead to different risks and, consequently, adverse effects on the stock portfolio. Among the factors are profit changes speed, which the lead to weaken the analysis of financial statements, the extremist reaction of investors, the lack of optimal portfolio allocation by them, and consequently, the increase in stock portfolio fluctuations. Therefore, the purpose of the present study is to investigate the relationship between the profit changes speed and stock portfolio fluctuations.Method: to the available features and information, 87 companies listed on the Tehran Stock Exchange were provided from 2009 to 2020. The Wang et al (2010) model was used to measure the speed of profit changes and The Kuronen (2013) model was used to measure the variable of stock portfolio fluctuations. The research hypotheses were also tested using the generalized least square regression model.Results: The results of the research confirm that there is a significant relationship between the rate of negative and positive profit changes and the stock portfolio fluctuations. In other words,It is expected that by identifying the factors that aggravate the volatility of the stock portfolio and controlling them, the investment risk can be minimized and inves