Trading volume was high at 546.5 million shares worth 4.65 trillion won ($3.92 billion), with losers outnumbering gainers 418 to 401.

Foreigners remained net buyers for the 12th consecutive session, scooping up a net 35.2 billion won Thursday. Institutions offloaded a net 10.9 billion won, while retail investors dumped 32.5 billion won.

"No one knows for sure why foreign investors continue to come into the local market, but the anticipated improvements in the quarterly results of local companies may have boosted their sentiment," Bookook Securities analyst Kim Sung-hwan said.

Top cap Samsung Electronics again reached a new record high of 1,940,000 won, spiking 1.36 percent from its previous record of 1,914,000 won set just one day before.

The tech giant has said its fourth-quarter operating profit was believed to have jumped nearly 50 percent on-year, beating previous market expectations.

Most other large caps finished in positive terrain.

Global chipmaker SK hynix plunged 1.94 percent to 50,600 won, one day after reaching a new 52-week high of 51,600 won, but top auto parts maker Hyundai Mobis spiked 1.64 percent to 279,000 won.

Top portal operator Naver added 0.75 percent to 802,000 won, while top chemical producer LG Chem surged 1.79 percent to 285,000 won.

The local currency closed at 1,184.70 won against the US greenback, up 11.70 won from the previous session's close.

Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys lost 2.0 basis points to 1.624 percent and the return on the benchmark five-year government bond dipped 4.7 basis points to 1.791 percent. (Yonhap)