China's Circuit Breaker Backfire: When a Safety Mechanism Made Things Worse
China introduced market-wide circuit breakers meant to calm panic selling — and pulled them after just four trading days, when the mechanism instead encouraged investors to sell faster, racing to get out before a halt locked them in.
- Circuit breaker lifespan
- 4 trading days
- Trigger thresholds
- 5% and 7% index moves
- Notable effect
- A 7% morning drop closed the market for the day, twice
What happened
Following a sharp market decline in the summer of 2015, Chinese regulators introduced a new circuit breaker system for the CSI 300 index, intended to reduce volatility: a 5% move would trigger a 15-minute trading pause, and a 7% move would halt trading for the remainder of the day.
The mechanism went live on January 4, 2016. On that day and again on January 7, the market fell fast enough to trigger the 7% threshold and close entirely — on January 7, trading lasted less than 30 minutes before the full-day halt kicked in.
Rather than calming the market, the design appeared to accelerate selling: because the thresholds were relatively close together (5% and 7%), and because a full-day closure meant investors could not trade at all once triggered, many rushed to sell as the market approached the 5% mark, trying to get out before a halt could trap their positions. Regulators suspended the entire system after only four trading days.
Why it still matters
This is a rare, well-documented case of a risk-management mechanism changing trader behavior in a way that undermined its own purpose — when a rule creates an incentive to race for the exits before it activates, it can concentrate selling rather than spreading it out.
It is a useful reminder for personal risk rules too: a stop-loss or a daily loss limit should reduce panic, not create a new reason to panic earlier. A limit set too close to normal volatility can produce the same effect on a much smaller scale — getting triggered by routine noise and forcing a reaction that a wider, better-calibrated rule would have avoided.