Global rating agency Moody's has upgraded South Korea's sovereign credit rating from Aa3 to Aa2 with an outlook of "stable." 

It's the first time ever for the country to receive an Aa2  rating from any of the three major global credit raters including Standard and Poor's and Fitch Ratings.

Moody's said that South Korea's foreign debt is only 30 percent of its gross domestic product and the percentage of its short-term foreign debt has also fallen below 30 percent. It said the figures point to improved fiscal soundness.

Only six other countries out of the Group of 20 nations have received an Aa2 rating or higher from Moody's.