I just read this interesting piece on how the Goldman Sachs Commodity Index (chart) was recently “tweaked” and could have caused a bit of a ruckus with some of the indexers who would have had to shuffle their investments. The short version: the recent selloff in oil and unleaded gas is a side-effect of indexers shifting to follow the new, lower weighting of unleaded gas in the index.

The author of the piece thinks that the timing was political, though I am not convinced.