Speculative bubble and stock return

The bubble in the stock market and in general in all markets is a real phenomenon that can cause losses to investors. The main problem facing each investor in the capital market is the decision to select the securities for investing and creating an optimal portfolio of stocks. Hence, stock valuation models have long been used by researchers  and investors. Solving  valuation puzzle reveals  the need to develop a comprehensive model that  describes the abnormal return . In this regards, although many efforts have been made and various models have been developed, none of these models has been able to fully explain this abnormal return. In this research, a pricing model in bubble conditions and an evaluation of the effective factors on stock returns are presented using the Fama-French model. For this purpose, the sample included 81 listed companies in the Tehran Stock Exchange( TSE) between 2009 and 2013, which have been selected . The results of this study reveal that among the five factors of the market, firm size, book value to price, momentum and bubble, only two factors of momentum and bubble affect the abnormal returns.