(LEAD) Seoul stocks open sharply lower on lingering concerns over AI, U.S. inflation

SEOUL, Oct. 15 (Yonhap) -- As concerns over the future of artificial intelligence (AI) and higher-than-anticipated inflation in the United States took hold, Seoul stocks plunged early Thursday. The Korea Composite Stock Price Index (KOSPI) fell 348.47 points, or 5.8 percent, bringing the benchmark index to 5,660.34 by 9:15 a.m. The steep decline prompted the country's stock exchange operator to issue a sell-side sidecar immediately after the market began trading.

Investor sentiment remained subdued, with major stock indexes on Wall Street also sliding overnight. The S&P 500 dropped 1.11 percent, while the tech-heavy Nasdaq fell 1.88 percent. In the United States, the Consumer Price Index rose 0.6 percent in September, increasing the annual inflation rate to 3.7 percent, well above economists' expectations of a 3.6 percent rise.

Notably, Korea's two leading chip manufacturers, Samsung Electronics and SK hynix, followed the downward trend of tech firms on Wall Street, with their shares sliding more than 6 percent and 8 percent, respectively. Hyundai Motor and defense firm Hanwha Aerospace also experienced declines, with their stocks dropping 4.31 percent and 0.24 percent, respectively.

Meanwhile, bio firm Celltrion saw a 1.39 percent decrease in share value. As of 9:15 a.m., the Korean won was valued at 1,343.3 won per U.S. dollar, a 1-won decrease from the previous trading session.