Investigating the intensity and weakness of herding behavior with a new method Based on stock market value in Tehran Stock Exchange

The purpose of this paper is to examine herding or collective behavior as one of the behavioral biases among investors. For this purpose, using the daily stock price information of 184 active companies listed in the Tehran Stock Exchange during the years 2013 to 2017 the existence of herding behavior in the Tehran Stock Exchange has been investigated with a new approach. The severity and weakness of this behavior during the years of research and effective observations on its occurrence were investigated and verified. To analyze the data, it is based on the principle of time series data and using standard scoring techniques and impact points. Findings of the study, while confirming the existence of herding behavior in all years of research, showed the distribution of the severity and weakness of the incidence of this behavior in a daily manner with effective observations. With the help of the technique of identifying effective points, the times of occurrence of collective behavior have been extracted. The results of this study showed that in the downtrend, more than the upward trends of herding behavior.