Following the U.S. Federal Reserve's decision to keep the interest rate steady, South Korea's main stock market index gained and the local currency appreciated against the weakened U.S. dollar. 

On the foreign exchange market, the value of the South Korean won strengthened 20 won against the greenback, the sharpest level in more than four years. The local currency closed at one-thousand-173-point-three won.

The benchmark Korea Composite Stock Price Index(KOSPI) on Thursday advanced 13-point-09 points, or zero-point-66 percent, to close at one-thousand-987-point-99.

The KOSPI marked two-thousand-point-30 points during the day as investors rallied following the U.S. Federal Reserve's announcement at the end of its two-day meeting on Wednesday.

The tech-heavy KOSDAQ, meanwhile, retreated one-point-95 points, or zero-point-28 percent, to 691-point-49.