Why did South Korean stocks fall on October 23, 2026?

Overnight losses in U.S. AI and semiconductor stocks weighed on Korean shares, while rising oil prices added to market jitters. Oil climbed amid concerns about possible supply disruptions after Yemen’s Iran-aligned Houthi rebels said they had again attacked key facilities in Saudi Arabia.

How did major U.S. technology stocks perform before Seoul shares fell on October 23, 2026?

U.S. stocks closed mixed, with technology losses weighing on the broader market. Micron Technology plunged 6.26 percent, Nvidia fell 4.4 percent and Intel tumbled 8.04 percent, while the Nasdaq Composite lost 2.6 percent.

How did Samsung Electronics and SK hynix shares move when Seoul trading opened on October 23, 2026?

Samsung Electronics, the market bellwether, fell 3.26 percent, while chipmaking rival SK hynix declined 2.21 percent. LG Energy Solution was down 2.56 percent, and Samsung Electro-Mechanics plunged 6.64 percent.

Seoul shares open sharply lower amid persistent AI woes, rising oil prices

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Summary

Korean shares fell sharply in Seoul on Friday, with the KOSPI down 2.83 percent to 5,377.17 as of 9:15 a.m. Losses in U.S. AI and semiconductor stocks and rising oil prices weighed on the market. Samsung Electronics, SK hynix and other large-cap shares also opened lower. The won traded at 1,325.8 per U.S. dollar.

Key Facts

The KOSPI opened 2.36 percent lower before falling 156.6 points.
The Nasdaq Composite shed 2.6 percent overnight, while the S&P 500 fell 1.21 percent and the Dow Jones Industrial Average rose 0.02 percent.
Micron Technology fell 6.26 percent, Nvidia dropped 4.4 percent and Intel declined 8.04 percent.
LG Energy Solution fell 2.56 percent, while Samsung Electro-Mechanics plunged 6.64 percent.
The won was up 0.7 won against the U.S. dollar from the previous stock trading session’s close.

By Yonhap

Published Oct 23, 2026 9:24 am KST

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

Korean shares opened sharply lower Friday, weighed down by overnight losses in U.S. artificial intelligence (AI) and semiconductor stocks, while rising oil prices added to market jitters.

After opening 2.36 percent lower, the benchmark Korea Composite Stock Price Index (KOSPI) fell 156.6 points, or 2.83 percent, to 5,377.17 as of 9:15 a.m.

Overnight, U.S. stocks closed mixed, with losses in major technology shares weighing on the broader market.

The Dow Jones Industrial Average rose 0.02 percent, while the S&P 500 fell 1.21 percent and the tech-heavy Nasdaq Composite shed 2.6 percent.

Micron Technology plunged 6.26 percent, while Nvidia and Intel tumbled 4.4 percent and 8.04 percent, respectively.

Renewed jitters over the AI industry dragged global markets lower, while oil prices climbed amid concerns over potential supply disruptions after Yemen's Iran-aligned Houthi rebels said they had again attacked key facilities in Saudi Arabia.

In Seoul, large-cap shares opened lower.

Market bellwether Samsung Electronics went down 3.26 percent while its chipmaking rival SK hynix declined 2.21 percent.

Battery maker LG Energy Solution fell 2.56 percent while Samsung Electro-Mechanics, an electronics component affiliate of Samsung Electronics, plunged 6.64 percent.

The Korean won was trading at 1,325.8 won against the U.S. dollar at 9:15 a.m., up 0.7 won from the close of the previous stock trading session.

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