The South Korean won has seen the biggest surge in its real effective exchange rate among emerging currencies since the U.S. Federal Reserve first hinted at tapering its quantitative easing two years ago, data showed Monday.

The won's real effective exchange rate was 113.46 as of end-March, 11.2 percent higher than in April 2013, when then Federal Reserve Chair Ben Bernanke signaled a reduction in its massive monetary easing, according to data by the Bank for International Settlements.

The REER refers to an index that describes the relative strength of a currency compared to a basket of other currencies, reflecting trade volume and inflation. The calculation uses 2010 as the base year and a reading above benchmark 100 means that a currency is overvalued.

Speculation over an interest rate hike in the U.S., the world's largest economy, has driven down most emerging market currencies against the greenback except South Korea and China, which pegs its currency to the dollar using a fixed exchange rate.

The corresponding figure for the U.S. and England each rose 13.4 percent and 12.8 percent over the cited period, while China marked a 14.3 percent hike, the Swiss-based bank said.

"Since Bernake's remark (on QE tapering), the global financial environment has changed as currency exchange rates in emerging economies have lost ground," Huh Jin-wook, a researcher at Samsung Securities, said. "Except the Chinese renminbi, the South Korean won is the only currency among emerging economies whose REER has advanced since then."

During the same period, the Japanese yen's REER decreased 11 percent on the back of Japanese Prime Minister Shinzo Abe's campaign, dubbed Abenomics, to end years of deflation and listless growth through massive fiscal and monetary policy easing measures.

The currency exchange gap between the two Asian nations rose to the highest since 2010, sparking worries over local exporters who compete with Japanese rivals in the global market in electronics and autos.

The won-yen arbitrated exchange rate stood at 898.52 won per 100 yen last Tuesday, the highest since Feb. 28, 2008, when the comparable figure was 889.23. The local currency closed at 1,070.00 won per dollar, up 3 won from the previous session's close, hitting a six-month high.

The U.S dollar serves as the benchmark currency for the exchange rate between the two, which tend to move together in their rates to the greenback.

"The wider currency exchange gap with the Japanese currency means that Korean companies become less price competitive, putting pressure on the Korean economy," Seo Dae-il, a researcher at KDB Daewoo Securities, said. "Local firms, including auto manufacturers, are suffering from the falling exchange rate of the yen against the won." (Yonhap)