South Korean stocks opened lower Wednesday, the last trading session this year, as investors sought to lock in gains after the benchmark index closed at an all-time high the previous session.

The benchmark Korea Composite Stock Price Index (KOSPI) fell 4.75 points, or 0.17 percent, to 2,815.76 in the first 15 minutes of trading.

Local stocks got off to a weak start, led by financial, tech and bio losses. The KOSPI closed at a record high for a third straight day Tuesday.

Market bellwether Samsung Electronics lost 0.38 percent, and No. 2 chipmaker SK hynix shed 0.43 percent.

Leading chemical firm LG Chem retreated 0.62 percent, and rechargeable battery maker Samsung SDI declined 0.5 percent.

Pharmaceutical giant Samsung Biologics moved down 0.24 percent, and Celltrion fell 1.94 percent.

But internet portal giant Naver gained 1.59 percent, with its rival Kakao rising 1.3 percent. Top automaker Hyundai Motor advanced 0.52 percent.

The local currency was trading at 1,090.15 won against the US dollar, up 1.95 won from the previous session's close.

The first trading session of the new year will open one hour later at 10 a.m. on Monday. It will close at the usual time of 3:30 p.m., according to the Korea Exchange (KRX). (Yonhap)