With all of the recent talk of the futures markets manipulating the price of XYZ commodity, I'd like to better understand the effect that futures markets, specifically the near month contract has on the cash market. For example - the oil market. Certain pundits say that there is a $5-$10-$30 premium to the "real" price in the futures market due to speculative demand. I understand how this might be true in the back months, and is not a very controversial statement to make. However, I also understand that at the time of contract expiration, all speculators will have had to rolled their exposure over to the next month by selling the current month, and buying the next. As all speculators are rolling over to the next contract, the only parties left on the bid will be physical hedgers. If there were to be a premium in the current contract, at expiration one would expect a huge sell off to the true demand/supply equilibrium. However, I am curious, given that all non-physical market participants are bidding up the back month contracts, how does this affect the spot market for the underlying? Is there any evidence that future (inflated) price of the commodity has an effect on the spot market? In other words, does an inflated back month contract exert an upward pressure on the actual spot market for a commodity?