Seoul's KOSPI falls another 7.57% and trips a circuit breaker, as Samsung drops 9.48% and SK hynix 11.06%, Yonhap reports

South Korea's main index fell 454.59 points, or 7.57%, to close at 5,554.22 on 15 October, Yonhap News Agency reported in a story carried by UPI. It had fallen as low as 5,450.81 during the day. It was the seventh straight session lower.

The Korea Exchange first triggered a sell-side “sidecar”, which pauses program selling, shortly after the open. At 12:38 p.m. it halted trading for 20 minutes, after the index had fallen more than 8%.

Samsung Electronics fell 9.48% to 210,000 won and SK hynix fell 11.06% to 1.26 million won, according to Yonhap. The two memory makers supply much of the memory used in AI data centres. Yonhap tied the fall to concerns about the sustainability of investments related to AI and to hot US inflation data for September.

What changed since the Switchboard's 13 October story, when the KOSPI fell 5.46% and SK hynix 10%: a deeper fall and the first circuit breaker of the sell-off. The fall came the morning after CoreWeave's shares lost 15.46% in New York on worries about its debt, and on the same day TSMC reported third-quarter profit up 68.7%.

The figures are Yonhap's; the Switchboard could not open the Korea Exchange's own data, so they carry reported status.

• Reported The KOSPI closed down 454.59 points, or 7.57%, at 5,554.22, its seventh straight losing session. Yonhap, via UPI
• Reported A circuit breaker halted trading for 20 minutes at 12:38 p.m. after the index fell more than 8%. Yonhap, via UPI
• Reported Samsung Electronics fell 9.48% to 210,000 won and SK hynix 11.06% to 1.26 million won. Yonhap, via UPI