Investor co-attention and stock return co-movement: Evidence from China’s A-share stock market

This study attempts to link investor co-attention to stock return co-movement in China's A-share stock market. On the one hand, stock price will co-move for stocks within the same industry and within the same market, which is labelled “return co-movement”. On the other hand, investor attention will also co-move as investors systematically search for relevant information for stocks of similar characteristics or as the stocks experience common information shocks, which is termed “investor co-attention”. The empirical evidence suggests that stock return co-movement can be explained by investor co-attention to a great extent, even after controlling for stock fundamentals and firm characteristics, and this effect is more salient for stocks with lower institutional ownership. Moreover, we employ large national lottery jackpots as exogenous shocks to investor attention. The empirical findings show that the co-movement of both investor attention and stock return increase on large lottery jackpot days, while investor co-attention contributes less to return co-movement on large lottery jackpot days. In summary, we offer an alternative explanation for return co-movement by observing the causal relationship between investor co-attention and stock return co-movement.