South Korean stocks closed at a record high Monday as pharmaceutical heavyweights posted strong gains amid the surging new coronavirus cases. The Korean won fell against the US dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) rose 6.47 points, or 0.23 percent, to close at 2,778.65.

Trading volume was high at about 1.1 billion shares worth some 18.7 trillion won ($17 billion), with gainers outnumbering losers 428 to 415.

Foreigners sold a net 8 billion won, while institutions purchased a net 132 billion won. Retail investors offloaded a net 88 billion won.

"Morning trading got off to a weak start as positive news from a US stimulus agreement was offset by COVID-19 lockdown concerns," KB Securities analyst Ha In-hwan said.

"But increasing bio gains seem to have pushed up the stock indices (in the afternoon)," he added.

Chip and auto heavyweights, the driving force in the KOSPI's rally last week, fared poorly due to investors' profit-taking, while steel, telecommunications and services advanced.

Market bellwether Samsung Electronics finished unchanged at 73,000 won, and No. 2 chipmaker SK hynix shed 2.11 percent to 116,000 won.

Hyundai Motor, the country's largest automaker, fell 1.06 percent to 170,000 won, while top steelmaker Posco advanced 2.04 percent to 274,500 won.

Top pharmaceutical firm Samsung Biologics gained 2.62 percent to 823,000 won, and Celltrion jumped 3.09 percent to 367,000 won.

Internet portal giant Naver rose 0.53 percent to 284,000 won, with its rival Kakao adding 3.41 percent to 379,500 won.

Leading chemical maker LG Chem edged up 0.12 percent to 815,000 won, but rechargeable battery maker Samsung SDI moved down 0.35 percent to 566,000 won.

The local currency closed at 1,102.7 won per dollar, down 3.0 won from the previous session's close.

Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys lost 0.4 basis point to 0.959 percent, and the return on the benchmark five-year government bond fell 2.2 basis points to 1.323 percent. (Yonhap)