South Korea temporarily halts KOSDAQ market algorithmic trading following sharp rise in stock index futures.

South Korea temporarily halts KOSDAQ market algorithmic trading following sharp rise in stock index futures.

South Korea’s Korea Exchange (KRX) temporarily suspended algorithmic trading on the KOSDAQ market on March 21, 2025, after the KOSDAQ 150 Futures index fell more than 3% within a five-minute window, triggering the sell-side sidecar mechanism. This automated safeguard imposed a five-minute trading halt for sell orders on stocks within the KOSDAQ 150 Index, while buy orders and trading for non-index stocks continued unaffected according to reports. The move aimed to curb rapid, disorderly sell-offs driven by algorithmic trading and allow liquidity to stabilize as analysis shows.

The activation followed heightened volatility in regional markets, with the KOSPI and KOSDAQ indices plunging over 8% on March 4, 2026, prompting broader circuit breakers and a 20-minute trading halt. Geopolitical tensions in the Middle East, including strikes and oil supply disruptions, exacerbated risk aversion, pushing oil prices to multi-month highs and intensifying pressure on export-dependent Asian economies. The Korean won weakened past 1,500 per dollar for the first time in 17 years, reflecting broader market uncertainty.

The KOSDAQ sidecar was the first such activation in four months, underscoring the mechanism's role as a last-resort tool during extreme volatility. Experts noted that while the trigger signaled short-term instability, it did not necessarily reflect long-term fundamentals. The KRX’s safeguards, refined since the 2022 “mini-flash crash,” emphasize transparency and fairness, with automated processes preventing manual intervention during halts.

Market participants remain cautious as geopolitical risks and energy price fluctuations continue to weigh on regional equities.