South Korean stocks turned a tad lower after starting marginally higher on Wednesday ahead of the release of China's purchasing managers' index.

The benchmark Korea Composite Stock Price Index fell 2.17 points, or 0.08 percent, to 2,591.14 in the first 15 minutes of trading.

Wall Street was closed Tuesday for the Independence Day holiday.

Later in the day, China is set to release the Caixin purchasing managers' index.

In Seoul, most large-cap shares opened in negative terrain.

Market bellwether Samsung Electronics dipped 0.27 percent, and No. 2 chipmaker SK hynix fell more than 1 percent.

Top battery maker LG Energy Solution and its smaller rival Samsung SDI both fell more than 0.8 percent. Leading chemical producer LG Chem also retreated over 1 percent.

Top automakers were mixed. Hyundai Motor was unchanged at 208,000 won ($160), but its affiliate Kia edged down 0.22 percent.

Bio stocks gained ground, with Samsung Biologics shooting up more than 2 percent and Celltrion jumping 1.87 percent.

Financial shares also advanced. KB Financial Group rose almost 1 percent, Shinhan Financial Group gained 0.44 percent and Hana Financial Group 0.51 percent.

The local currency was trading at 1,300.00 won against the US dollar at 9:15 a.m., up 1.4 won from Tuesday's close. (Yonhap)