Samsung and SK Hynix together account for more than half of the KOSPI’s weighting, according to Reuters. In practice, it has become a highly sensitive expression of the global AI memory trade. That is the same tension behind the broader AI memory chip supercycle. Korea JoongAng Daily said a KOSPI sidecar is triggered when KOSPI 200 futures fall by at least 5% from the reference price and remain there for one minute. KOSPI is down today because Samsung Electronics and SK Hynix sold off sharply during a global semiconductor rout.