What it is
Circuit breakers pause the entire market after a steep index drop to give investors time to cool off.
Triggers
If KOSPI (or KOSDAQ) falls 8% or more from the prior close for one minute, trading halts for 20 minutes (stage 1). At 15% another 20-minute halt follows (stage 2); at 20% trading ends for the day (stage 3). Each stage triggers once a day, and stages 1 and 2 do not trigger after 14:50.
What to keep in mind
KOSPI circuit breakers have fired after the September 11 attacks in 2001, during the March 2020 COVID-19 crash and in the August 2024 sell-off, among others. They differ from the sidecar, which only pauses program trading.
What happens during the halt
Trading in stocks and the related derivatives stops and outstanding orders are cancelled. When trading resumes it does not go straight back to continuous matching: orders are collected for 10 minutes and reopened at a single price. If stage 3 fires, after-hours trading is cancelled as well.
Where to check it
The Korea Exchange announces a trigger and brokers show it immediately. For how a sharp day played out, see our market close summary and morning briefing. Halts on a single stock — the volatility interruption and trading suspensions — appear in that stock filings instead.
This explanation is general information, not investment advice. Rules reflect September 2026 and may change; check official exchange and broker notices.