Oil prices and financial speculation

It is possible to buy what are known as futures contracts which are linked to oil prices on the stock market. These days, given the uncertainties in the stock market, and also the rising price of oil, many investors are interested in commodities, including oil, to diversify their portfolios. Indeed, some have suggested, as detailed in this article, that financial speculation is playing some role in keeping oil prices so high. Of course, it's also difficult to say by how much.