The benchmark Korea Composite Stock Price Index added 1.9 points, or 0.08 percent, to 2,417.95 in the first 15 minutes of trading.
On Tuesday (local time), US stocks closed at fresh record highs, with the S&P 500 inching up 0.11 percent and the Dow gaining 0.18 percent.
Most large caps on the Seoul bourse traded mixed, with marking kingpin Samsung Electronics shedding 0.04 percent.
SK hynix, a major chipmaker, was up 0.13 percent.
LG Chem, South Korea's top chemicals firm, surrendered 1.01 percent, while AmorePacific, the country's No. 1 cosmetics firm, gained 0.4 percent.
Automakers were among the gainers, with industry leader Hyundai Motor climbing 1.07 percent.
The local currency was trading at 1,130.70 won against the US dollar, up 0.60 won from the previous session's close. (Yonhap)