Here is Spot Crude with the single bull Crude ETF:USO in blue and the double bull Crude ETF:UCO in gray. One would think the double bull would outperform the single and spot Crude easily, especially in uptrends. Not so. Note over the last full year the single bull ETF:USO has tracked spot Crude well as it tends to do and also outperformed the double bull ETF:UCO especially so since last October. Double ETFs do not always perform as one would expect. The way these leveraged ETFs are calculated often give results like this. And they often under perform the underlying and decay in value over time regardless. They were designed for very short term trading. See link bottom left.