The exchange traded fund (ETF) iShares MSCI South Korea Index (EWY) just keeps going and going. When we reported on it just last month, it was already up an impressive 22% for the year. Now, it’s up 37% for the year and shows no signs of stopping.

What’s causing the growth spurt this time?

One theory is that Moody’s Investors Service put the South Korean government ratings on its list to be reviewed for a possible upgrade because of the country’s diligence in fiscal prudence and positive large economic prospects, according to Polya Lesova of MarketWatch.

"Korea’s favorable macroeconomic performance should continue over the near term," said Thomas Byrne, senior vice president at Moody’s in a statement Tuesday. "Over the longer term, Korea’s improved credit fundamentals reflect a renewed commitment to trade liberalization to boost potential economic growth."

With performances and predictions like this, EWY might be the next Energizer bunny.

Tags: Asia, South Korea