WPI recently received a question from a client asking, in effect, if global crop prices have become immune – or at least less sensitive – to changes in global crop ending stocks. The reasoning offered was the perception that corn futures are becoming less responsive to declining global corn ending stocks/use (ESU) ratios, or global stocks excluding China. Evidence of this supposed phenomenon was a chart showing global corn stocks excluding China on one y-axis and CBOT corn futures on the other y-axis. The chart, which we were unable to republish but created a similar graph below, appeared to show that CBOT futures once held a strong, negative correlation to world ex-China ESU ratios, but that correlation was dissipating over the...