Let's just say it is a fancy financial invention intended to bilk more money from investors.

The PowerShares DB G10 Currency Harvest Fund (DBV) simulates the so-called currency carry trade, tracking a Deutsche Bank AG (DB) index comprised of six of the Group of Ten, or G10, currencies: U.S. dollar; euro; Japanese yen; Canadian dollar; Swiss franc; British pound; Australian dollar; New Zealand dollar; Norwegian krone, and Swedish krona.

"The index is designed to exploit the trend that currencies associated with relatively high interest rates, on average, tend to rise in value relative to currencies associated with relatively low interest rates," according to the ETF's prospectus.

Accordingly, the sophisticated index reflects long futures positions in the three currencies with the highest interest rates, and short positions in the three with the lowest rates. However, if the U.S. dollar is one of the three highest or lowest-yielding currencies, the ETF will not take a long or short position because investors are already buying shares with their home currency.

The leveraged long-short index reviews the currencies of countries with the highest and lowest rates and rebalances quarterly.

Short-term Treasury bills provide collateral for the futures. This fixed-income portion of the portfolio generates yield, which is used to offset the ETF's fees.

Therefore, investors get a return from both the Treasury yield and the movement in the currency futures. However, capital gains from "rolling" the futures contracts are taxed at a higher rate than stocks -- 40% of the gains are considered short-term and 60% are long-term gains.