Currency exchange traded funds have seen rising investor interest in 2011 but inflows have cooled over the past month as investors worried about global debt jitters pile into precious metals ETFs, particularly gold.

“The Greek crisis and U.S. debt limit debate seem to have sucked capital away from almost all currencies and into hard assets for the moment,” said Nicholas Colas, chief market strategist at ConvergEx Group. “A reversal of these trends — likely when the U.S. debate is finally resolved — will be a good sign that risk appetites are on the rise again.”

Year to date, more money has gone into currency ETFs — $2.2 billion — than commodity ETFs, with the big winners including CurrencyShares Swiss Franc Trust (NYSEArca: FXF), CurrencyShares Canadian Dollar Trust (NYSEArca: FXC) and WisdomTree Dreyfus Brazilian Real (NYSEArca: BZF).

The Swiss franc ETF has attracted $541 million so far in 2011 and accounts for nearly 25% of all new capital in U.S.-listed currency ETFs, according to Colas.

“Great performance doesn’t hurt, of course, but it’s the reasons for the strength in the Swiss franc that likely piques investor interest,” Colas wrote in a note Tuesday. “A strong central bank, some isolation from the troubles in Europe and the U.S., and a history of safe haven status among its many private banks all help.” [Swiss Franc ETF Hits Fresh Peak on Debt Jitters]