Commonality in individuals' trading: A systematic path between behavioral bias and expected returns

This paper investigates whether there is commonality in the trading of individual investors. To test for the existence of trading commonality, we apply three different methods employed in assessments of commonality in liquidity. Using actual individual trading in the Korean stock market, we demonstrate the strong commonality in individual trading. Additionally, we find evidence that commonality in individual trading predicts future stock returns, and its' predictability is significant in medium-size stocks. The Korean market also shows strong commonality in liquidity, but it has little relation to commonality in individual trading in explaining stock returns.

► We demonstrate the strong commonality in individual trading in the Korean stock market.
► Commonality in individual trading predicts future stock returns.
► We also confirm a high and significant liquidity commonality in the Korean stock market.
► Commonality in individual trading has little relationship with commonality in liquidity.