Why did the KOSPI fall sharply on Thursday morning?

Investor sentiment weakened after U.S. stocks closed lower amid concerns about whether artificial intelligence spending can continue at its current pace and after September U.S. inflation data raised market concerns. The resulting sell-off focused on major technology shares in Seoul.

Which Korean stocks were hit hardest during the October 15 sell-off?

Chipmakers Samsung Electronics and SK hynix recorded the steepest declines among the major companies listed in the report, falling 7.87 percent and 9.87 percent, respectively. Hyundai Motor dropped 5.1 percent, while KB Financial and Hanwha Aerospace also declined.

What happened to trading and the Korean won as Seoul stocks plunged?

The KOSPI’s early loss of more than 5 percent prompted the bourse operator to suspend trading temporarily for five minutes. At 11:20 a.m., the won was trading at 1,350 per U.S. dollar, weakening 7.7 won from the previous session’s close.

Seoul stocks extend losses as AI, US inflation concerns persist

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Summary

Seoul stocks fell sharply in Seoul late Thursday morning as concerns about artificial intelligence spending and U.S. inflation data triggered a sell-off in major technology shares. The KOSPI dropped 404.21 points, or 6.73 percent, to 5,604.6 as of 11:20 a.m., after an earlier decline of more than 5 percent temporarily halted trading. Samsung Electronics and SK hynix led losses, while Celltrion was among the few gainers.

Key Facts

The KOSPI’s early decline of more than 5 percent triggered a five-minute temporary trading suspension by the country’s bourse operator.
The U.S. Consumer Price Index rose 0.6 percent in September from the previous month, its fastest increase since April.
Samsung Electronics fell 7.87 percent and SK hynix declined 9.87 percent, while Hyundai Motor dropped 5.1 percent.
Celltrion gained 3.13 percent, making it one of the few stocks to rise during the sell-off.
The Korean won traded at 1,350 won against the U.S. dollar at 11:20 a.m., down 7.7 won from the previous session’s close.

By Yonhap

Published Oct 15, 2026 9:16 am KST
Updated Oct 15, 2026 11:39 am KST

The benchmark KOSPI is displayed at a dealing room of Hana Bank in Seoul, Thursday. Yonhap

Seoul stocks were trading sharply lower late Thursday morning as concerns over artificial intelligence (AI) trade and U.S. inflation data sparked a sell-off of major tech shares.

The benchmark Korea Composite Stock Price Index (KOSPI) fell 404.21 points, or 6.73 percent, to 5,604.6 as of 11:20 a.m.

In early trading, the benchmark index had fallen over 5 percent, triggering the country's bourse operator to temporary suspend trading for five minutes.

Overnight, U.S. stocks closed lower as concerns over the sustainability of AI spending and September consumer price data dampened investor sentiment.

The U.S. Consumer Price Index (CPI) for September rose 0.6 percent from a month earlier, the fastest level seen since April, according to official data released Wednesday (U.S. time).

In Seoul, most market top caps were trading lower.

Chip titans Samsung Electronics and SK hynix tumbled 7.87 percent and 9.87 percent, respectively.

Industry leader Hyundai Motor fell 5.1 percent, financial firm KB Financial slid 1.13 percent and defense giant Hanwha Aerospace dipped 1.54 percent.

Among the few winners was bio firm Celltrion, which added 3.13 percent.

The Korean won was trading at 1,350 won against the U.S. dollar as of 11:20 a.m., down 7.7 won from the close of the previous stock trading session.

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