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South Korean stocks tumbled more than 4 percent on Thursday, dragged down by losses in tech shares amid lingering concerns over the profitability of artificial intelligence (AI) spending. The benchmark Korea Composite Stock Price Index (KOSPI) fell 4.58 percent, or 301.88 points, to close at 6,296.38, after falling as low as 6,238.32 during the session, according to Yonhap News Agency.

The decline came after two consecutive days of gains, during which the index had risen 1.62 percent and 3.76 percent on Tuesday and Wednesday, respectively, driven by eased concerns over AI profitability. Thursday's sell-off was prompted by a sharp fall in U.S. chip stocks and profit-taking, analysts said.

Coverage Comparison

Yonhap News Agency provided multiple reports on the same market event, with some variations in detail. One report, published during trading hours, noted the KOSPI fell 4.52 percent as of 11:20 a.m., while the closing reports put the final decline at 4.58 percent. The earlier report also mentioned that the index had opened 1.81 percent lower and that the Korea Exchange (KRX) activated a sell-side sidecar for the KOSPI for five minutes at 10:18 a.m., halting program trading for KOSPI-listed shares.

The more detailed closing report added that trade volume was light at 281.8 million shares worth 25.9 trillion won (US$18.2 billion), with winners outnumbering losers 489 to 380. It also broke down investor activity: foreigners sold a net 3.33 trillion won worth of stocks, institutions offloaded a net 121.8 billion won, while individuals purchased a net 3.34 trillion won.

Overnight on Wall Street, the tech-heavy Nasdaq Composite lost 0.83 percent, its first decline in five sessions, as investors sold off Nasdaq-listed tech heavyweights like Alphabet and Advanced Micro Devices on doubt about the profitability of large-scale investment in AI infrastructure. In contrast, the Dow Jones Industrial Average rose 0.49 percent to a new record high, helped by signs of eased tensions in the Middle East.

Key Claims

KOSPI closes down 4.58%

The KOSPI fell 4.58 percent to close at 6,296.38, according to Yonhap's closing reports. An earlier intraday report put the decline at 4.52 percent as of 11:20 a.m., illustrating the continued slide through the session.

Tech and semiconductor shares lead losses

Market bellwether Samsung Electronics sank 5.89 percent, and its chipmaking rival SK hynix slumped 8.75 percent, as semiconductor shares were the biggest losers, Yonhap reported. Samsung Electro-Mechanics, an electronics component affiliate, plunged 9.11 percent, and SK Square, the parent of SK hynix, dived 11.62 percent. Top carmaker Hyundai Motor dropped 2.35 percent, while leading energy firm Doosan Enerbility lost 1.69 percent.

Defensive and earnings-driven gains

Some stocks bucked the downtrend. Defense giant Hanwha Aerospace rose 4.67 percent in the closing reports, though an earlier report put the gain at 4.17 percent. Cosmetics maker APR jumped 4.34 percent on its solid second-quarter earnings, while Samsung Biologics gained 1.54 percent.

Currency and bond market moves

The local currency rose against the U.S. dollar. The Korean won was trading at 1,416.25 won against the dollar as of 11:20 a.m., up 8.65 won from the close of stock trading the previous day, according to Yonhap. Bond prices closed lower, though the report did not specify yields.

Analyst commentary

Han Ji-young, an analyst at Kiwoom Securities, was quoted in the more detailed reports as saying: "Despite improvement in geopolitical and macroeconomic conditions, the KOSPI lost momentum due to losses in U.S. chip stocks and profit-taking," noting that investors still want to see strong evidence of massive AI spending and growth. He added, "However, investors' concerns over AI spending seemed to have already peaked following recent earnings reports by big tech companies."