SEOUL, Feb. 4 (Yonhap) — South Korean stocks opened lower Thursday largely on tech and pharmaceutical losses.

The benchmark Korea Composite Stock Price Index fell 18.48 points, or 0.59 percent, to 3,111.2 in the first 15 minutes of trading.

Stocks quickly fell to the negative terrain due to strong foreign and institutional selling, after the key index rallied 5.2 percent in the past three sessions.

Top cap Samsung Electronics lost 1.42 percent, and No. 2 chipmaker SK hynix shed 1.92 percent.

Pharmaceutical giant Samsung Biologics declined 0.97 percent, with Celltrion retreating 2.01 percent.

Top automaker Hyundai Motor added 2.24 percent, with its smaller affiliate Kia Motors gaining 2.87 percent.

Leading chemical firm LG Chem moved down 0.8 percent, while rechargeable battery maker Samsung SDI climbed 0.26 percent.

The local currency was trading at 1,114 won against the U.S. dollar, up 0.9 won from the previous session’s close.