The carry trade is all about selling currencies with low interest rates and buying currencies with high interest rates. You profit from the interest rate spread ... aka, the carry ... and away you go. It's the same thing DBV does, except that DBV is unlevered; typically, carry trades are levered up at 10:1 or more.

But I think it's a good thing that it's unlevered, as the key thing about DBV is its pattern of steady long-term returns with relatively low correlations to the market. And despite the fact that it's been a bit more volatile than I suspected when it first launched, it has in general delivered on its promise. The fund is up about 4% since inception in late-2005, compared to a 2% loss on the S&P 500. Not bad, all things considered.

It's one of the best examples I can think of, of an institutional strategy delivered to retail investors in an ETF package.