South Korean stocks extended gains for a third consecutive session Wednesday, as investors held out optimism for progress in the US stimulus talks. The Korean won rose against the US dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) added 12.45 points, or 0.53 percent, to close at 2,370.86.

Trading volume was moderate at 802 million shares worth some 9.7 trillion won ($8.6 billion), with gainers outnumbering losers 675 to 183.

Foreigners bought a net 6.4 billion won, while retail investors sold a net 131 billion won. Institutions purchased a net 115 billion won.

"Local stocks got a boost from US peers, largely as optimism for the new stimulus plan has weakened the US dollar and raised the investor appetite for risk," said Kiwoom Securities analyst Seo Sang-young.

The KOSPI was boxed in a tight range, however, since most of such anticipation was already projected in the stock prices in the previous sessions, he added.

Market bellwether Samsung Electronics closed flat at 60,900 won, and No. 2 chipmaker SK hynix shed 1.64 percent to 83,800 won.

Top pharmaceutical firm Samsung Biologics gained 0.88 percent to 688,000 won, while Celltrion lost 0.61 percent to 244,000 won.

Internet portal giant Naver advanced 2.59 percent to 297,500 won, with its rival Kakao climbing 0.28 percent to 353,500 won.

Leading chemical maker LG Chem fell 0.64 percent to 617,000 won, and rechargeable battery maker Samsung SDI edged up 0.12 percent to 433,000 won.

Hyundai Motor, the country's largest automaker, declined 1.19 percent to 165,500 won, while top steelmaker Posco advanced 0.24 percent to 207,000 won.

The local currency closed at 1,131.9 won per dollar, up 7.5 won from the previous session's close.

Bond prices, which move inversely to yields, closed lower. The yield on three-year Treasurys rose 2.3 basis points to 0.934 percent, and the return on the benchmark five-year government bond added 5.7 basis points to 1.224 percent. (Yonhap)