The Impact of Investor and Managers' Behavioral Bias on the Stock Price Bubble in capital market of Iran

In emerging capital markets, the inability of investors to analyze financial information, scarcity of information, as well as the impact of macroeconomic and political factors on financial markets, causes the investor to focus on market excitement and the behavior of other investors. The emotional and herd behaviors of investors are the source of the emergence of various anomalies such as price bubbles and the formation of sharp fluctuations in the market. Managers also have behavioral biases such as overconfidence, myopia and narcissism, which leads to a favorable image of the business and delays in presenting bad news, resulting in stock price bubbles. Accordingly, the purpose of this study is to investigate the effect of biases of investors and managers' behavior on the stock price bubble. The research sample included 129 companies listed on the Tehran Stock Exchange in the period 1392 to 398.To test the hypotheses, multivariate regression method with combined data was used.The results show that investors' behavioral distortions (emotional and herd behavior) increase the gap between the intrinsic stock price of the company and its value set by investors and lead to the formation of stock price bubbles. Managers' behavioral biases (overconfidence myopia and narcissism) also lead to the emergence of stock price bubbles.