摘要：The paper examines the impact of changes in the positions of financial actors on the volatilities of Chicago grains and vegetable oil prices using a GARCH-X framework within which a variant of Granger-causality tests can be performed. The paper analyses both the position data in the post-2006 CFTC Commitments of Traders reports and the data on index provider positions in the Supplemental reports. A test of the Masters hypothesis that index trading increase volatility fails to find support.
