U.S. stock index futures were lower, with Dow Jones Industrial Average futures off 11 points.

WSJ: Asia Markets Slip on Oil

Its benchmark is the Dow Jones UBS Commodity Index and it does not invest directly in commodity futures.

FORBES: One High-Yielding Commodity Play

One of the best ways to trade copper prices besides futures contracts is the iPath Dow Jones-UBS Copper Sub-Index Total Return ETN ( JJC).

FORBES: A Panic Low in Copper, FCX?