Air pollution, individual investors, and stock pricing in China

We construct a firm-level index for measuring the mood of individual investors induced by air pollution in the Chinese stock market. In a setting where individual investors dominate the stock market, we examine how the individual investor mood affects stock pricing. We find that the investor mood only affects individual investors' trading behaviors, thereby validating the individual investor mood indices. Further, a pessimistic individual investor mood decreases liquidity and volatility, eventually causing a decline in stock returns. The mispricing caused by the individual investor mood cannot be eliminated by using risk-factor models, thereby implying the limited efficiency of the Chinese stock market.