One of the main problems with commodity-based ETF’s is that they don’t necessarily track the underlying commodity very well. This is mainly due to the fact that the ETF is forced to trade the futures contracts, and there are times when it isn’t feasible for the ETF managers to roll from one futures contract to the next without making a “losing” trade that puts “drag” on the performance of the ETF vis-a-vis the spot index or commodity itself.
