The study looked at how stock market returns in China behave, focusing on the Shanghai-Shenzhen stock index. They found that the tails of the stock index returns are thicker than expected, meaning extreme events happen more often than in a normal distribution. The right tail (high returns) is fatter than the left tail (low returns), showing asymmetry. The Shanghai stock market has more fluctuations compared to Shenzhen, but it attracts more investors. Stock index returns in China change significantly after daily price limits, with Shanghai experiencing even bigger changes.