Intraday momentum and reversal in Chinese stock market

Taking intraday first-half-hour returns as predictor, we find significant intraday momentum and a reversal effect in the Chinese stock market. This momentum and reversal effect is robust even when including previous day returns, overnight returns, and day-of-week effect. We confirm that noise trading is the driving factor that causes the predictability of intraday returns. Although the investment strategy based on the first-half-hour returns can generate abnormal returns, the presence of costs prevents arbitrageur's intervention and makes the intraday returns predictability exist persistently.