Thanks Chris for the response. I thought the fall in crude prices was more due to demand destruction from the sharp global recession, not speculators.

Rogers makes the case that is more about supply and demand balance with the commodities themselves. The world has not been investing in metal mines, oil wells, coffee trees, sugar, etc… for a long time. And it takes a lot of time to ramp up (build new mines, coffee trees take 3 years, etc…) commodities and bring on more supply. And of course that coupled with continued big demand from China and other emerging economies. Leeb makes a lot of the same points. And of course both authors lean towards the peak oil arguement.

The reason my interest in a commodities index fund was for looking for a place to put a small percentage of portfolio. The index fund seems like a way to have some money in commodities themselves without having to trade futures of individual commodities.