Kospi plunges after Wall Street bails out of tech shares
After choppy trading, the benchmark Kospi fell 9.01 points, or 0.33 percent, to close at 2,746.46.
Trading volume was high at about 1.2 billion shares worth 20.3 trillion won ($18.6 billion), with gainers outnumbering losers 659 to 192.
The Kospi retreated after a 2.02 percent gain the previous session, led by massive foreign selling.
Foreigners dumped a net 1.4 trillion won, while retail investors purchased a net 893 billion won. Institutions bought a net 442 billion won.
The Kospi's fall was led by shares in tech giants, tracking a 1.94 percent overnight plunge on the Nasdaq composite. The U.S. Federal Trade Commission's antitrust lawsuit against Facebook curtailed investor appetite for tech heavyweights.
Volatility remained high the entire session, with the Kospi plunging over 1 percent in the morning and briefly spiking to another all-time high in the afternoon.
Analysts said uncertainties increased on "the quadruple witching day," or the expiration day of four key derivatives, including Kospi-tracking options and futures, which occur four times a year.
"Sell-offs increased from the quadruple witching day, but strong individual buying buffered the Kospi's further plunge," said Bookook Securities researcher Lee Won.
In Seoul, most large caps closed lower.
Samsung Electronics lost 1.35 percent to 72,900 won, and chipmaker SK hynix shed 3.32 percent to 116,500 won.
Pharmaceutical firm Samsung Biologics retreated 0.36 percent to 819,000 won, while Celltrion gained 1.84 percent to 360,000 won.
Internet portal giant Naver declined 0.69 percent to 286,000 won, with its rival Kakao down 1.2 percent to 370,500 won.
Chemical maker LG Chem fell 2.27 percent to 817,000 won, and rechargeable battery maker Samsung SDI dropped 1.06 percent to 560,000 won.
Hyundai Motor, the country's largest automaker, closed unchanged at 191,500 won, and steelmaker Posco dropped 0.37 percent to 272,000 won.
The Kosdaq rose 7.89 points, or 0.86 percent, to close at 921.70.
The local currency closed at 1,087.7 won per dollar, up 2.9 won from the previous session's close.
The return on the three-year bond closed unchanged at 0.974 percent, and the return on the 10-year bond gained 2.3 basis points to close at 0.94 percent.
BY CHEA SARAH, YONHAP [firstname.lastname@example.org]