Abstract:
This study investigates the role of liquidity as an additional factor in asset pricing and as an indicator of the relative dominance of the irrationally overconfident investors in the market. Data used are based mainly on monthly data of common stocks registered with Stock Exchange of Thailand, from 1994 to 2004. I use illiquidity ratio as a proxy of liquidity. I firstly investigate the role of liquidity in asset pricing and find that the liquidity augmented CAPM model is the best model for explaining abnormal return. Moreover, I find that liquidity premium has positive sign as expected. For the study of the role of liquidity as an indicator of the relative dominance of the irrationally overconfident investors in the market, I investigate the dependence of momentum profitability on the state of the market. The market state is defined on the basis of market return and market liquidity. I find that high-liquidity states are associated with higher momentum profits than low-liquidity states when the market experiences recent gains. These findings are consistent with the model of Baker and Stein (2002), in which irrational investors become active only when their sentiment is positive and their dominance in the market results in higher market liquidity. However, these results are significant only in case of lagged market liquidity 3 months. In addition, I find that momentum profits after adjusted momentum profit by risk factors are closer to zero.