Short-term market reaction after trading halts in Chinese stock market

• We study the dynamics of several financial measures after the trading halts.
• The dynamics share the same pattern with a sharp peak and a power law relaxation.
• Inter-day halts are most effective, while one-day halts are least effective.
• In case of intraday halts and one-day halts, positive events decay faster.
• Conversely, in case of inter-day halts, negative events decay faster.

In this paper, we study the dynamics of absolute return, trading volume and bid–ask spread after the trading halts using high-frequency data from the Shanghai Stock Exchange. We deal with all three types of trading halts, namely intraday halts, one-day halts and inter-day halts, of 203 stocks in Shanghai Stock Exchange from August 2009 to 2011. We find that absolute return, trading volume, and in case of bid–ask spread around intraday halts share the same pattern with a sharp peak and a power law relaxation after that. While for different types of trading halts, the peaks’ height and the relaxation exponents are different. From the perspective of halt reasons or halt durations, the relaxation exponents of absolute return after inter-day halts are larger than those after intraday halts and one-day halts, which implies that inter-day halts are most effective. From the perspective of price trends, the relaxation exponents of excess absolute return and excess volume for positive events are larger than those for negative events in case of intraday halts and one-day halts, implying that positive events are more effective than negative events for intraday halts and one-day halts. In contrast, negative events are more effective than positive events for inter-day halts.