As you're probably aware, oil this year surged to $147 a barrel and then fell to, as of today, about $40 -- over a 2/3 drop in less than six months. And its peak was over a 100% increase from the previous year. With a lot of the decline shortly before the election, this roller-coaster ride has prompted quite a lot of conspiracy theories.
Well, recently on another (private) forum, I summarized the significant reasons why oil acted like that, without reference to any conspiracy. I'll repeat it here:
1) China was buying a lot of oil and stockpiling it. Unlike the general "growth in emerging markets", this actually came as a surprise to a lot of speculators, which is why it was such a fast rise instead of a gradual one since 2000. China was doing this in order to burn less coal and make the air cleaner for the Olympics. Now that that's over, a significant source of demand is gone.
2) Because of the credit crunch, speculators were significantly less able to borrow and bid up the price of oil. Once it hit, they had to significantly unwind their positions.
(Now, I'm all for the right of people to make speculative purchases; however, what we had there was *far* from a free market. For one thing, the government's bailing out of banks that had hedge funds doing the speculating, eliminated the strong negative downside to hype-based, stupid speculation. Also, a lot of the *naked* shorts and longs were very corrupt where if one party lost money, the brokerage would act like it can't find the original contract and try to reverse the sale. Things like this artificially amplified the price premium due to hype [as opposed to rational estimations of future developments] and crowded out wiser investors.)
3) The global economic downturn significantly revised investors' estimates of future oil demand.
4) The president's, and then congress's, termination of the ban on offshore drilling also significantly changed expectations about future oil availability. These helped prod oil down.