At 11:23 a.m. on July 24, the South Korean exchange (KRX) once again rang the “circuit breaker bell”—the KOSPI market sell-side Sidecar was activated, pausing algorithmic sell orders for 5 minutes. The trigger conditions are mechanical: the KOSPI 200 futures nearby-month contract fell 5% versus the previous trading day and sustained that level for a full minute. At that time, the KOSPI broke below the 7,000-point psychological threshold, with an intraday quote of 6,769.51 and a decline of 4.61%.

Major-weight stocks were all deep in the red. Samsung Electronics (005930.KS) fell 6.11% to 253.5k won, and SK Hynix (000660.KS) dropped 5.99%. The KODEX KOSPI ETF (226490), which tracks the broader index, also came under pressure. With futures-spot linkage in play, KOSPI 200 futures became the “first domino” in this selloff.

Tensions in the Middle East flared up again, and worries about rising oil prices were the final straw that broke sentiment. For foreign investors, semiconductor positions were overly crowded; for local institutions, the decline in KOSPI 200 futures directly ignited the Sidecar mechanism. This marked the 17th sell-side Sidecar event on the main board since the start of this year—far exceeding the total of 3 times for all of 2025, and even breaking the 26-time annual record set during the 2008 financial crisis.

Sidecar is essentially a “cooling-off period”—pressing a 5-minute pause button on automated selling so the spot market can catch its breath. But for holders of index funds like 226490, a 5% drop in futures isn’t just a trading pause—it’s a repricing of risk. If you can read Sidecar, you can read the temperature of sentiment in the Korean market.