The South Korean currency suffered one of the largest depreciations globally in December due to the political crisis following President Yoon Suk Yeol's botched martial law attempt.

According to the Bank of International Settlements (BIS) on Sunday, the index of real effective exchange rate (REER) of the Korean currency reached 91-point-03 at the end of December, down one-point-99 points from a month earlier.

The index measures the strength of a currency relative to a basket of other currencies, with a reading above 100 indicating appreciation compared to the base year, while a reading below the benchmark means the opposite.

Among the BIS-listed 64 countries, South Korea's index was the second lowest, trailing only Japan's 71-point-three.

The decline of one-point-99 points was also the third steepest after Brazil's three-point-94 point drop and Australia's two-point-37 point fall.

The monthly fall marks South Korea's largest drop in 27 months since September 2022, when it slipped two-point-92 points.