South Korean stocks rebounded Thursday on the quadruple expiration day of options and futures, buoyed by strong advances in tech stocks and massive foreign buying. The Korean won fell against the US dollar.

The benchmark Korea Composite Stock Price Index (Kospi) rose 8.46 points, or 0.26 percent, to close at 3,224.64 points.

Trading volume was high at about 1.9 billion shares worth some 18.8 trillion won ($16.8 billion), with losers outnumbering gainers 426 to 418.

Foreigners scooped a net 710 billion won, the largest daily purchase since March 11, and retail investors purchased 387 billion won. Institutions sold a net 1.11 trillion won.

The Kospigot off to muted start as investors take a wait-and-see approach before the US consumer price index (CPI) for May is published later in the day (Korean time).

The price gauge is expected to provide hints of the direction of the Fed's economic diagnosis in the Federal Open Market Committee meeting next week.

The key stock index gained ground as of late morning, helped by advances by Kakao, Naver and SK Telecom.

Mobile text messenger operator Kakao's stocks jumped upon the regulator's preliminary approval for its insurance business. South Korea's major mobile carrier SK Telecom spiked after it announced that it will spin off a new investment company in November and split its shares.

Despite the inflation uncertainties, foreigners raked in futures and options at the main bourse on the four witches' day.

"Volatility was high in local stock markets ahead of the US CPI data release and influences of the quadruple expiration of futures and options," Daeshin Securities analyst Lee Kyung-min said.

In Seoul, market bellwether Samsung Electronics slipped 0.12 percent to 81,000 won, while No. 2 chipmaker SK hynix added 0.41 percent to 123,000 won.

Internet portal operator Naver surged 4.18 percent to 373,500 won, with Kakao jumping 3.49 percent to 133,500 won. Giant pharmaceutical firm Samsung Biologics increased 2.52 percent to 855,000 won.

Top automaker Hyundai Motor lost 1.46 percent to 236,000 won, but leading chemical firm LG Chem increased 0.62 percent to 807,000 won.

The local currency closed at 1,115.8 won against the US dollar, down 0.4 won from the previous session's close. (Yonhap)