The upside circuit break has very practical implications. China's current stock market was started in 1990. The general public began to paying attention to stock market around 2000. From the historical point of view, both the stock market and the general public's understanding on it are still in early stage. So the attitude on stock market is very speculative. Coincidentally, the economy in China has been undergoing stunning growth during this period, which generates a huge amount of wealth. This furthers the stock market's speculative nature. As a result, the volatility could be very high. It was not uncommon to see some stocks undergo several +/-20% changes during a week, before the upside circuit breaker was established. Its primary purpose is to curb the speculation.