South Korean stocks opened lower Monday on increased valuation pressure, after the benchmark index closed at an all-time high the previous session despite surging new coronavirus cases.

The benchmark Korea Composite Stock Price Index (KOSPI) fell 4.18 points, or 0.15 percent, to 2,768.0 in the first 15 minutes of trading.

Stocks got off to a weak start as foreigners and institutions are set to lock in gains as the country's soaring COVID-19 cases increased concerns of stronger social distancing measures.

Chip and auto heavyweights led the KOSPI's retreat, while pharmaceuticals advanced.

Market bellwether Samsung Electronics slipped 0.14 percent, and No. 2 chipmaker SK hynix shed 1.69 percent.

Hyundai Motor, the country's largest carmaker, lost 0.79 percent.

Leading chemical firm LG Chem slid 0.12 percent, and rechargeable battery maker Samsung SDI retreated 0.88 percent.

Pharmaceutical giant Samsung Biologics moved down 0.25 percent, but Celltrion jumped 2.95 percent.

Internet portal giant Naver gained 0.53 percent, with its rival Kakao rising 2.04 percent.

The local currency was trading at 1,099.5 won against the US dollar, down 0.2 won from the previous session's close. (Yonhap)