South Korean shares closed more than 1 percent higher Wednesday on a rally in top cap Samsung Electronics and before the results of the Federal Reserve's rate-setting meeting. The local currency stayed unchanged against the US dollar.

The benchmark Korea Composite Stock Price Index surged 33.97 points, or 1.28 percent, to close at 2,690.14.

Trade volume was heavy at 710 million shares worth 12.6 trillion won ($9.3 billion), with gainers outnumbering losers 481 to 380.

Foreign investors turned to net buyers, scooping up 840.4 billion won worth of local shares, while institutions also purchased a net 586.6 billion won. Retail investors dumped a net 1.4 trillion won.

Wednesday's market advance was largely attributed to a sharp gain in market kingpin Samsung Electronics after US tech firm Nvidia hinted at potential cooperation with the world's largest supplier of memory chips.

The market rally also came one day after it lost more than 1 percent as investors took to the sidelines ahead of the US Federal Open Market Committee's two-day rate setting meeting, set to end Wednesday.

"The advance by Samsung Electronics was the largest reason for the increase in Kospi," said Kim Dae-joon, a researcher at Korea Investment & Securities. "The reason Samsung Electronics rose while SK hynix fell is because of Nvidia."

Samsung Electronics, which accounts for nearly one-quarter of market capitalization here, spiked 5.63 percent to close at 76,900 won, while its local rival and the world's No. 2 chipmaker SK hynix lost 2.31 percent to 156,500 won.

Lead battery maker LG Energy Solution gained 1.12 percent to 407,500 won, with its local rival Samsung SDI adding 0.44 percent to 453,000 won.

Automakers closed mixed with market leader Hyundai Motor advancing 1.47 percent to 241,000 won, while its smaller affiliate Kia Motors shed 2.69 percent to 115,700 won.

The local currency closed at 1,339.80 won against the US dollar, unchanged from the previous session's close. (Yonhap)