In October 1987, the United States stock market experienced the largest crash in history, with the Dow Jones Index dropping by -22.6% in a single day.
Due to the lack of a circuit breaker mechanism and limits on price fluctuations, many millionaires became poor overnight. This day was also known in the financial world as "Black Monday."
In October 1988, the US stock trading commission approved the circuit breaker mechanism. When the index fell by 7% within a short time, all markets would suspend trading for fifteen minutes.
It took nine whole years until October 1997 for the US stock market's circuit breaker mechanism to be triggered for the first time.
The US stocks needed time to test the feasibility of circuit breakers, but Big A emphasizes efficiency, with two circuit breakers in four days, four triggers, and a thousand stocks hitting the limit—twice. A new level above the old, indeed.