Companies are cross-listed on multiple exchanges in different countries to take advantage of different market features. Due to the difference in time zones, it is normally quite impossible to take advantage of instantaneous information spillover from market to market to generate abnormal returns. Situations can be different if the cross-listed firms are traded in markets within the same country and in the same time zone, but with different legislative regimes and levels of sophistication. Focusing on investors’ herd behavior and using hourly data, this article finds evidence of cross market information spillover in herding formation and abnormal returns in cross-listed stocks in China’s Shanghai, Shenzhen, and Hong Kong markets. More importantly, we find that investors can make excess returns upon observing herding by buying and holding Hong Kong’s small and median stocks in industrial sectors cross-listed in the Shenzhen market especially in the morning and the end of the trading day.