The most popular instruments are foreign currency futures on the Chicago Mercantile Exchange.

FORBES: In The Money

Futures markets determine foreign exchange rates, and in a world of gyrating currency values there are serious questions about whether they are the best way to determine the relative value of dollars, euros and yen.

WSJ: Book Review: The Futures

The economy is improving, but Jessica Hoversen, a foreign exchange and fixed-income futures analyst at MF Global, warns that the currency market may have already overextended itself in the short term, while long-term trends endanger the U.S. dollar.

FORBES: Magazine Article