Foreign exchange reserves consist of securities and deposits denominated in overseas currencies, as well as International Monetary Fund reserve positions, special drawing rights and gold bullion.

The BOK said that the recent strength of the US dollar decreased the value of non-dollar currencies when converted into the greenback.

In October, the US dollar index rose 2.2 percent on-month against the currencies of six major economies.

The value of foreign securities, such as government bonds and corporate debts, amounted to $375.78 billion last month, up $150 million from a month earlier.

Foreign currency-denominated deposits fell $440 million on-month to $16.71 billion in October.

The country's reserve position at the IMF stood at $2 billion at the end of October, while holdings in gold bullion were also unchanged at $4.79 billion during the same period, the central bank said.

As of end-September, South Korea ranked eighth in the world in terms of the amount of foreign reserve holdings. China topped the list, followed by Japan, Switzerland, Saudi Arabia and Taiwan, according to the BOK. (Yonhap)