Seoul, October 13, 2026: South Korea’s Korea Exchange activated a sell-side sidecar on Tuesday morning after a sharp decline in the stock market. The five-minute restriction began at 9:48 a.m. Seoul time, according to Yonhap, citing the exchange.
At 9:50 a.m., the benchmark KOSPI stood at 6,127.15, down 257.09 points, or 4.03%. It had opened 3.1% lower. These are time-stamped morning figures, not the closing result for October 13.
What triggered the KOSPI sidecar?
Yonhap reported selling in semiconductor shares, including Samsung Electronics and SK hynix, as weakness in US technology stocks affected sentiment ahead of major earnings reports and US inflation data. That is the news agency’s account of the market backdrop; it does not identify a single proven cause for every sell order.
The sidecar trigger concerns KOSPI 200 futures, rather than the percentage move in the broader KOSPI cash index. Yonhap reported that the sell-side measure is triggered when those futures fall at least 5% for a minute.
A sidecar is not a complete market shutdown
The exchange’s published trading explanation describes a temporary suspension of the validity of program-trading quotations. In a falling market, the measure applies to program-selling quotations for five minutes.
That distinction is important. A headline saying the stock market stopped trading altogether would overstate what this mechanism does. The sidecar targets a defined category of program orders; it is not the same as a circuit breaker that suspends the wider market.
Why cash-index and futures figures differ
The KOSPI reading reports the movement of the broad stock benchmark. KOSPI 200 futures are a separate instrument linked to a narrower index. A 4.03% cash-index decline can therefore be reported alongside a futures-based sidecar trigger without implying that the trigger threshold was 4%.
The exchange’s market guide explains the distinction between these volatility controls. Readers should check the instrument, direction of movement and time before comparing percentages.
How to read the rest of today’s session
The morning intervention establishes that a volatility threshold was reached. It does not predict whether shares will recover or fall further. Later prices and the final close will need separate reporting; they should not be inferred from this early snapshot.
This report explains the market event and trading mechanism. It does not recommend buying or selling securities.
The Business Desk covers markets, the economy, companies and personal finance. Stories are checked against at least two credible sources before publication.
