Kospi Drops 3.26% as Foreign, Institutional Investors Sell Net 4.46 Trillion Won; Chip Stocks Hammered

The Kospi tumbled more than 3% on Sept. 14, falling back into the 6,600 range as worries over tighter monetary policy ahead of the Federal Open Market Committee meeting combined with worsening sentiment toward artificial intelligence investments.

The Kospi closed at 6,684.37, down 225.54 points, or 3.26%, from the previous session. Selling pressure intensified immediately after the open, dragging the index into the mid-6,600s. It later trimmed some losses and briefly recovered to the mid-6,700s, but downside pressure strengthened again in the afternoon.

Foreign and institutional investors led the selloff. Foreign investors were net sellers of 3.287 trillion won in the benchmark market, while institutions sold a net 1.172 trillion won. Retail investors, by contrast, bought a net 2.972 trillion won during the decline.

U.S. stocks rose across the board on Sept. 11 as falling oil prices lifted the major indexes. The Dow Jones Industrial Average gained 0.98%, the S&P 500 rose 0.86%, and the Nasdaq added 0.96%. The Philadelphia Semiconductor Index also advanced 1.81%.

In South Korea, however, caution over monetary policy weighed more heavily ahead of this week's FOMC meeting. U.S. core consumer prices for August rose 0.3% from a month earlier, above the 0.2% market forecast, reviving concerns about another rate increase. A high-oil-price, high-interest-rate environment tied to uncertainty in the Middle East also pressured investor sentiment.

Semiconductor shares came under added pressure after calls spread over the weekend, particularly among major U.S. big tech companies, to slow the pace of AI development. That sharpened concerns over the growth trajectory of the AI industry and triggered concentrated selling in South Korea's large-cap chipmakers.

Samsung Electronics fell 4.05% and SK Hynix slumped 6.35%. Other semiconductor and information-technology stocks also posted steep losses, including Samsung Electronics preferred shares, down 5.12%, SK Square, down 8.17%, and Samsung Electro-Mechanics, down 4.50%.

The Kosdaq also finished lower. The index closed at 806.79, down 13.85 points, or 1.69%, from the previous session. It retreated to the low-800 range during the session and later recouped part of the loss, but failed to turn positive.

On the Kosdaq market, retail investors bought a net 109 billion won, while foreign and institutional investors sold a net 93 billion won and 30 billion won, respectively. Among large-cap stocks, Alteogen fell 2.99%, Ecopro lost 3.44%, Ecopro BM dropped 5.88%, Jusung Engineering declined 1.44%, and Rainbow Robotics slipped 3.21%.

Separately, the Korea Exchange began operating an after-market session on Sept. 14 that allows investors to trade stocks in real time after the close of the regular session.