Speculation about causes
High food prices have made the rise of agricultural commodity prices a politically controversial issue. One of the most controversial elements has been the role of investors, particularly hedge funds, in futures markets, which have been blamed for high prices by some observers.
Although there have been isolated incidents of market manipulation in commodity futures markets, such as Amaranth’s ill-fated activities in the US natural gas market in 2007, investors and hedge funds are less significant players than many believe. A study by Barclays Capital in July found that the amount being invested in commodity markets was greatly exaggerated, and a recent study by consultancy Celent found that hedge funds account for only 10% to 20% of transactions, far less than investment banks.
An IMF study in 2006 concluded that price causality ran, in general, from spot prices to financial flows, implying that higher spot prices are the cause rather than the effect of increased investor participation.
A 2008 OECD study, however, observed that commodity futures and cash markets had on occasion failed to converge and that: "Conceivably, it could also be due to the ‘inflation’ of futures prices being caused by increasingly large long positions placed by institutional investors."
Although speculators might help to drive intra-seasonal price trends, there is no evidence that they are doing anything like hoarding physical supplies that could affect inter-seasonal prices.