SEOUL, April 21 (Yonhap) — South Korean stocks opened lower Wednesday after the benchmark stock index closed at an all-time high the previous session, increasing the valuation pressure.

The Korea Composite Stock Price Index (KOSPI) fell 23.07 points, or 0.72 percent, to 3,197.63 points.

The KOSPI quickly fell through the 3,200-point mark with the opening bell as foreign and individual investors sold stocks to lock in gains. The stock index gained for the past six days until Tuesday amid expectations of a global economic rebound and better earnings reports in the January-March season.

In Seoul, market kingpin Samsung Electronics shed 0.95 percent, and No. 2 chipmaker SK hynix retreated 1.08 percent.

Internet portal giant Naver declined 1.28 percent, with its rival Kakao decreasing 0.42 percent. Leading carmaker Hyundai Motor lost 0.87 percent.

Giant chemical maker LG Chem fell 1.23 percent, and top pharmaceutical firm Samsung Biologics dropped 0.96 percent.

The local currency was trading at 1,117.35 won to the U.S. dollar as of 9:15 a.m., down 5.05 won from the previous session’s close.