The main obstacles to the creation of an Asian Currency Unit are the choice of currencies that would be included, the severe misalignments between the various regional currencies and the economic turmoil of 2007-2008. There have been a number of financial instruments that use baskets of Asian currencies, but these are individually constructed and are not sponsored or used as a means of exchange in the countries represented. The most well-known investment vehicles include exchange traded notes (ETNs) and structured notes, whose returns are based on Asian currency baskets.