South Korean stocks opened lower Friday after three consecutive sessions of gains as investors cashed in profits ahead of Federal Reserve Chair Jerome Powell's speech at the Jackson Hole symposium.The benchmark Korea Composite Stock Price Index (KOSPI) fell 10.91 points, or 0.4 percent, to 2,696.76 in the first 15 minutes of trading.Overnight, the Dow Jones Industrial Average closed 0.43 percent lower, with the S and P 500 falling 0.89 percent. The tech-heavy Nasdaq composite decreased 1.67 percent as well.Powell is to deliver a speech at the Jackson Hole meeting on Friday (U.S. time), which will give clues on the Fed's monetary policy direction.In Seoul, top tech giant Samsung Electronics fell 0.51 percent, and No. 2 chipmaker SK hynix lost 1.73 percent.Leading battery maker LG Energy Solution added 0.41 percent, while Samsung SDI slid 0.15 percent.Pharmaceutical firms started higher, with Samsung Biologics rising 0.1 percent and Yuhan climbing 0.73 percent.The local currency was trading at 1, 342 won against the U.S. dollar, down 7.3 won from the previous session's close.Source: Yonhap News Agency