Circuit breaker in the stock market: What caused Korean shares to halt trading?

On March 4, the impact of the Middle East conflict caused the Korean stock market to temporarily halt trading

Why did the KOSPI set off a stock market circuit breaker?

Following increased volatility in reaction to the Middle East conflict, South Korean stocks fell 12% on March 4 and the nation's main stock exchange was forced to temporarily halt trading.

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

According to Susannah Streeter, chief investment strategist at Wealth Club, shares on the KOSPI "dived into freefall mode." Given how dependent the nation is on imports, investors were concerned about the effects of high energy prices, which caused the index to finish 12% lower. The "

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Start your trial Following increased restrictions through the Strait of Hormuz, a crucial shipping route that connects the Persian Gulf and the Gulf of Oman, Korean stocks were particularly severely impacted by the panic that swept through Asian markets. The strait is used to transport about 20% of the world's oil, but Iranian forces have essentially blocked the route.

As a result of the disruption, stocks sold off throughout Asia. Taiwan's Taiex dropped 4.4 percent, while Japan's Nikkei 225 fell 3.6 percent.

However, Korea suffered the most, partly due to its reliance on oil imports, its export-oriented economy (which is thought to be susceptible to trade disruption), and the fact that this appears to be where international investors have assets to sell.

As of February 27, 2026, the KOSPI had increased by more than fifty percent. As investors fled stocks due to uncertainty, they locked in these gains.

What does a stock market circuit breaker mean?

KRX's twenty-minute pause isn't as out of the ordinary as you might think.

To control volatility and guard against disorderly selloffs, most stock exchanges have a system in place that temporarily stops trading in the event of significant, abrupt price changes in an index (or, in some cases, individual stocks).

They were first created in the wake of the 1987 Black Monday stock market crash, which resulted in the loss of years' worth of gains in a matter of hours, partly due to automated trading programs that were still relatively new at the time.

If the SandP 500 drops by 7%, 13%, or 20% in a single session, circuit breakers are activated.

According to theory, circuit breakers stop panic selling, which slows the index's decline.

Can stocks in Korea rise again?

This was the biggest one-day decline in KOSPI's history, but it's important to remember that the index closed on March 4th up 21% through 2026 and more than 100% over the previous 12 months, highlighting the fact that these investments provided a handy source of liquidity at a time when investors were in a panic.

The future course of Korean stocks is largely dependent on how and when the Strait of Hormuz situation is resolved.

Emma Wall, chief investment strategist at Hargreaves Lansdown, stated that "the downward pressure on stocks is likely to continue until this crucial trade route is made safe." "With the volatility we have come to expect as the norm under a Trump presidency, we expect markets to return to optimism once secured. A "