South Korea's foreign reserves have hit another record high, rising over four billion U.S. dollars in May. 

According to the Bank of Korea(BOK) on Thursday, the nation's foreign currency reserves reached a fresh high of 456-point-46 billion dollars as of the end of last month, up four-point-15 billion dollars from a month earlier. 

The previous record of 452-point-three billion dollars was set in April. 

The central bank said the rise in May is attributed to increased returns on its foreign currency assets and the U.S. dollar's weakness that drove up the value of other currencies when converted into the greenback. 

As of the end of April, South Korea was the world's eight-largest holder of foreign exchange reserves, rising one notch from the previous month.

China topped the list at over three-point-one trillion dollars, followed by Japan and Switzerland.