What goes up must come down. Since the start of 2008 the Brazilian real (BRL) has made double-digit moves in both directions. From January through Aug. 1, the real gained 14.1 percent vs. the U.S. dollar. But the currency quickly began to unravel, falling a stunning 25.6 percent vs. the greenback as of Sept. 18.

Forex traders are wondering whether this reversal is simply a temporary, if dramatic, interruption to the real’s long-term uptrend (similar to the summer 2007 episode) or the beginning of a new downtrend. Regardless, the road ahead will likely be rocky.