The Task Force on Commodity Futures Markets, established by the International Organization of Security Commissions to look into these matters, reviewed the available research and came to the conclusion that they “do not support the proposition that the activity of speculators has systematically driven commodity market cash or futures prices up or down on a sustained basis”. In its October 2008 World Economic Outlook, the IMF concluded that there was no evidence of a long term systemic effect due to speculation on commodity prices, although it suggested that short term expectations can be influenced by sentiment and investor behaviour, which can amplify short-term price fluctuations, as in other asset markets. On the other hand, Tang and Xiong (2010) conclude that as a result of the bundling of commodities in index funds correlations among commodities have gone up and that shocks from oil and financial factors now spill-over more strongly to non-energy commodities.