South Korean stocks turned lower after starting marginally higher Friday, driven by a decline in big tech companies.

The benchmark Korea Composite Stock Price Index lost 7.9 points, or 0.31 percent, to 2,542.12 in the first 15 minutes of trading.

Overnight, major US stock indexes ended mixed as major banks cleared the Federal Reserve's annual stress test, while stronger-than-expected economic data bolstered expectations of an additional rate hike by the Fed.

The Dow Jones Industrial Average rose 0.8 percent, and the S&P 500 went up 0.5 percent, while the Nasdaq Composite closed almost flat.

In Seoul, large-cap tech stocks led the downturn.

Tech heavyweight Samsung Electronics fell 0.83 percent, and No. 2 chipmaker SK hynix lost more than 2 percent.

Top battery maker LG Energy Solution also dropped 0.36 percent, and its smaller rival Samsung SDI went down 1.5 percent.

Bio firms also retreated, with Samsung Biologics sliding 0.53 percent and Celltrion losing 0.66 percent.

Auto stocks gained. Top automakers Hyundai Motor rose 1.22 percent, and Kia advanced 1.63 percent on expectations they will post robust earnings in the second quarter. Hyundai Motor's auto parts-making affiliate, Hyundai Mobis, jumped almost 2.5 percent.

The local currency was trading at 1,323.6 won against the US dollar at 9:15 a.m., down 6 won from Thursday's close. (Yonhap)