Black Monday 2025-04-07: a sell sidecar triggered by foreign futures selling
A record of 2025-04-07, when tariff fears sank the KOSPI 5.57% and triggered the first sell sidecar since 2024-08. It lays out a flow picture in which foreign futures selling pulled the trigger while individuals and institutions absorbed the supply.
Updated Oct 13, 2026
Trigger log: 2025-04-07 09:12
At 09:12:11 on 2025-04-07, KOSPI 200 futures printed 312.05, down 5.19% from the prior close, and program sell orders in the securities market were suspended for 5 minutes. The trigger requires KOSPI 200 futures to stay down 5% or more from the base price for 1 minute. Foreigners' KOSPI 200 futures selling of more than 7,000 hundred-million won pulled the trigger.
Close and flows
The KOSPI closed at 2,328.2, down 137.22 points or 5.57%, for 4 straight down sessions. The KOSDAQ fell 5.8% as well; volume was 615.2 million shares worth 10.5 trillion won, with 862 decliners against 68 advancers. Foreigners net sold 2.09 trillion won of cash shares while individuals bought 1.67 trillion won and institutions 2,532 hundred-million won, and the won logged its steepest fall since the pandemic.
Precedent: selling in 2024-08, buying on 08-06
On 2024-08-05, a steep fall on spreading US recession fears triggered a KOSPI sell sidecar, and the next day, 2024-08-06, a sharp rebound triggered a buy sidecar. The record shows the day after a trigger can go either up or down.
How to read a sidecar day
A sidecar only suspends program trading for 5 minutes; it differs from a circuit breaker that halts the whole market. Since the 2025-04-07 trigger was foreign futures selling, the trigger's weight can only be gauged by watching futures flows alongside cash flows. The 2024-08-05 and 2024-08-06 record shows a trigger alone sets no next-day direction. This video's rout centers on foreign cash selling, a different kind of trigger, so compare with attention to who supplied the flow and at what scale.
Limits of this case
The 2025-04-07 case was a rout from an external variable, tariffs, differing in nature from a rout rooted in a sector variable like CXMT. Nothing guarantees the post-trigger moves of the past will repeat this time. Trigger conditions and figures may change with rule revisions.
Sources
- KOSPI Circuit Breaker Triggered on 'Another Black Monday' - Program Sell Order Effectiveness Suspended (Update)Accessed Oct 13, 2026
- Kospi plummets 5.57% over U.S. tariff uncertaintyAccessed Oct 13, 2026