Stock market circuit breaker: Why did Korean shares pause trading?

The fallout from the conflict in the Middle East hit the Korean stock market on 4 March, with shares forced to temporarily stop trading. What is a stock market circuit breaker, and why did the KOSPI trigger one?

The Korea Composite Stock Price Index (KOSPI) and the Korean Securities Dealers Automated Quotations (KOSDAQ) displayed at the Korea Exchange (KRX) in Seoul, South Korea, on Wednesday, March 4, 2026. Panic swept through South Korea's trading floors as concerns over the Middle East conflict sent the world's hottest stock market to its biggest-ever selloff
(Image credit: SeongJoon Cho/Bloomberg via Getty Images)

South Korean stocks fell 12% on 4 March, and the country’s main stock exchange was forced to temporarily stop trading, following heightened volatility in response to the conflict in the Middle East.

The Korea Exchange (KRX) activated a twenty minute circuit breaker on both the Korea Composite Stock Price Index (KOSPI) and its tech-heavy Korea Securities Dealers Automated Quotations (KOSDAQ) market, after the KOSPI fell 8.1% within hours of the market opening.

Try 6 free issues of MoneyWeek today

Get unparalleled financial insight, analysis and expert opinion you can profit from.

Start your trial
https://cdn.mos.cms.futurecdn.net/flexiimages/mw70aro6gl1676370748.jpg

Sign up for MoneyWeek’s free twice-daily newsletter.

Join more than 165,000 subscribers and keep yourself informed with latest financial news, insights and expert analysis to help you understand what really matters when it comes to your finances.

Join more than 165,000 subscribers and keep yourself informed with latest financial news, insights and expert analysis to help you understand what really matters when it comes to your finances.

Sign up
Latest Videos FromMoneyWeek
Dan McEvoy
Investment editor

Dan is a financial journalist who, prior to joining MoneyWeek, spent five years writing for OPTO, an investment magazine focused on growth and technology stocks, ETFs and thematic investing.

Before becoming a writer, Dan spent six years working in talent acquisition in the tech sector, including for credit scoring start-up ClearScore where he first developed an interest in personal finance.

Dan studied Social Anthropology and Management at Sidney Sussex College and the Judge Business School, Cambridge University. Outside finance, he also enjoys travel writing, and has edited two published travel books.