Recently, companies cannot produce customer services because of COVID-19. This leads the index of stock to change rapidly. So, on March 9th, the New York Stock Market activated the circuit breaker.

Circuit breaker is a method to stop the index of stocks from soaring and plunging by temporarily stopping the stock trading. This method was first used in New York, United States. Its phrase is actually from an operated electrical switch that protects the main machine from electrical damage which causes the overload of current. there are three levels when the circuit breaker is activated. When the stock declines seven percent from its closing price the day before, it starts level one by halting the trading for 15 minutes. When the stock declines 13 percent from its closing price the day before, it starts level two by halting the trading for 15 minutes unless it is after 3:25#pm using the Eastern Standard Time. When the stock declines 20 percent from its closing price the day before, it starts level three by halting the trading for the rest of the day. It helps the stock market to stop the index of stocks from changing quickly. However, a circuit breaker is also a very dangerous way because it stops trading stocks for a long time. The New York Stock Exchange says that they will review the circuit breaker after the outbreak of COVID-19 since it is a quite dangerous way to use it often.

The circuit breaker was not being used until the New York Stock Market first used it in October 1997. Then since COVID-19 is a serious problem in the whole world these days, the circuit breaker is of great help. This circuit breaker system is also effective in South Korea, as it stops the index of stocks from changing rapidly in a short period of time.