I find commodity index buying eerily reminiscent of a similar craze for portfolio insurance which led to the stock market crash of 1987.

In both cases, the institutions are piling in on one side of the market and they have sufficient weight to unbalance it. If the trend were reversed and the institutions as a group headed for the exit as they did in 1987 there would be a crash.

When the idea was first promoted, there was a rationale for it ... But the field got crowded and that profit opportunity disappeared.

The euro cannot replace the dollar as the world's main reserve currency, and a system of two reserve currencies would be unstable. There is a commodities bubble still in the growth phase while other bubbles are being deflated.
-Billionaire investor, George Soros June 3, 2008