South Korean currency surged against the U.S. dollar on Thursday on rising uncertainties about economic policy of the Trump administration in the United States.

The won/dollar exchange rate finished at 1,186.3 won per dollar, down 20.1 won from the previous close. It marks the South Korean currency's fastest appreciation to the dollar in about six months.

The dollar's ascent had recently been fast on the expected three rate hikes in 2017 by the U.S. Federal Reserve, but expectations for the Fed's rate increases got lower on uncertainties about economic policy in the U.S..

According to the December FOMC minutes, the U.S. central bankers were uncertain about economic outlook after a new administration is launched on Jan. 20.

Stocks in South Korea ended in a negative territory as the local currency's ascent to the greenback has a negative impact on domestic exporters, but the main index trimmed losses thanks to foreign purchases of local stocks.

The benchmark Korea Composite Stock Price Index (KOSPI) lost 3.69 points, or 0.18 percent, to settle at 2,041.95. Trading volume stood at 525.27 million shares worth 3.99 trillion won (3.37 billion U.S. dollars).

Foreign and individual investors bought stocks worth 84 billion won and 63 billion won each. Financial institutions offloaded a net 163 billion won worth of shares.

Market bellwether Samsung Electronics declined 1.7 percent, and the biggest steelmaker POSCO lost 2.8 percent. The most-used search engine Naver dipped 2.4 percent, but the No.1 auto parts maker Hyundai Mobis advanced 1.6 percent.