This chart shows the net position of both hedge funds (green shaded) and index funds (blue shaded), with the scale measured in futures contracts. One contract is about 100 bales. The combined net speculative position has an apparent influence on price (the red line) in the short run (see here for more discussion and interpretation). Statistically, the hedge fund position build-up in early 2014 is associated with 9 cents of the twelve cent price rally that occurred then. Similarly, hedge fund liquidation and outright selling is associated with 11 of the 24 cent price decline after May 2014.
Note: Not surprisingly, the fluctuations in the hedge fund position correlate very well with the shifts in the pattern of open interest, although sometimes there is a lag. The data from this chart come from the CFTC Commitment of Traders report. Additional description and interpretation of the CFTC data is available here.