An exchange traded fund based on the 11 developed member countries of the Eurozone has nearly tripled the return of the S&P 500 the past six months while assets have grown rapidly due to hefty inflows. The outperformance reflects improved sentiment on Europe’s ability to weather its debt crisis as well as a strengthening euro in currency markets.

The iShares MSCI EMU Index Fund (NYSEArca: EZU) is up 29.9% the over the last six months while the SPDR S&P 500 (NYSEArca: SPY) has gained 10.7%, according to data.

The Eurzone ETF has been outperforming the S&P 500 fund by a wide margin since mid-July. Also, a strengthening euro versus the U.S. dollar during the period has helped since EZI does not hedge its foreign currency exposure.

The European portfolio has been beating the U.S. blue-chip index despite lingering concerns over Europe’s debt crisis. The showdown over the fiscal cliff in late 2012 may have provided a tailwind to EZU as investors looked outside the U.S.

Still, restricting a European portfolio to the members of the Monetary Union “can be a risky proposition,” writes Morningstar analyst Alex Bryan in a report on EZU.

“Unlike most pan-European funds, it excludes companies based in the United Kingdom and Switzerland, which are among the largest stock markets in Europe. These countries have also weathered the global financial crisis better than many of their peers,” he said.

The Eurozone ETF charges an expense ratio of 0.52% and holds assets of about $2.3 billion, according to manager BlackRock (NYSE: BLK).