Seoul: The South Korean won strengthened to a nine-month high against the U.S. dollar, following suspected market-smoothing operations by the nation's foreign exchange authorities. The won was quoted at 1,418 won per dollar as of around 6 a.m., marking its strongest level since October 20 of the previous year.

According to Yonhap News Agency, the won had advanced to as high as 1,419 won per dollar on Thursday night (Seoul time) but later pared gains, trading at the 1,430-won level by 9:37 a.m. The appreciation of the won coincided with a gain in the Japanese currency. At one point during New York trading, the yen rose to about 158 per dollar, reaching its strongest level in more than two years.

Lee Min-hyuk, an analyst at KB Kookmin Bank, noted the correlation between the won and yen, raising speculation that both South Korean and Japanese foreign exchange authorities might have intervened in the markets. "The overnight strength of the won and the yen could suggest the authorities in South Korea and Japan may have intervened together," Lee speculated.