The benchmark Korea Composite Stock Price Index inched down 2.56 points, or 0.11 percent, to 2,362.91 in the first 15 minutes of trading.
On Tuesday (local time), the major Wall Street indexes hit record highs, with the S&P 500 Index adding 0.2 percent and the tech-heavy Nasdaq composite index gaining 0.12 percent.
Large-cap stocks on the Seoul bourse were mostly in negative terrain, with market bellwether Samsung Electronics losing 0.12 percent and steelmaker POSCO decreasing 0.74 percent. Global chipmaker SK hynix, meanwhile, was up 0.27 percent.
The local currency was trading at 1,128.7 won against the US dollar, up 0.5 won from the previous session's close. (Yonhap)