South Korean stocks closed nearly flat Thursday as investors cashed in gains from large-cap chip and auto stocks amid valuation pressure in sectors such as chipmaking and automaking. The Korean won fell against the US dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) rose 1.64 points, or 0.05 percent, to 3,149.93.

Trading volume was high at about 1.2 billion shares worth around 23.8 trillion won ($21.7 billion), with gainers outnumbering losers 518 to 320.

Foreigners scooped up a net 673.4 billion won, and retail investors purchased a net 718.9 billion won. Institutions offloaded a net 1.43 trillion won.

The main index traded choppy throughout the session, swinging between positive and negative terrain, as investors offloaded major chip and auto stocks.

"Chip and auto stocks that recently exhibited steep gains showed signs of fatigue," Kiwoom Securities analyst Seo Sang-young said.

The KOSPI refreshed record highs last week on the back of stellar rises in top cap Samsung Electronics and Hyundai Motor.

Investor sentiment gathered ground in the afternoon session on hopes for more US stimulus.

US President-elect Joe Biden is expected to unveil his plan to prop up the world's largest economy before taking office.

Most large caps in Seoul closed lower.

Market bellwether Samsung Electronics remained unchanged at 89,700 won, while No. 2 chipmaker SK hynix lost 1.88 percent to 130,500 won.

Top automaker Hyundai Motor declined 3.28 percent to 250,500 won, while auto parts affiliate Hyundai Mobis dropped 3.68 percent to 327,000 won.

Pharmaceutical firm Samsung Biologics fell 1.69 percent to 816,000 won, and Celltrion tumbled 7.6 percent to 352,500 won.

Leading chemical firm LG Chem advanced 1 percent to 1,010,000 won, while rechargeable battery maker Samsung SDI moved down 0.66 percent to 749,000 won.

Internet portal operator Naver added 1.27 percent to 318,000 won, while rival Kakao slipped 0.66 percent to 451,500 won.

The local currency closed at 1,098.0 won against the US dollar, down 2.9 won from the previous session's close.

Bond prices, which move inversely to yields, closed lower. The yield on three-year Treasurys added 0.9 basis point to 0.988 percent, and the return on the benchmark five-year government bond rose 1.4 basis points to 1.324 percent. (Yonhap)