Everyone in agricultural markets has been surprised by the increase in corn stocks with the latest USDA report, yet we only have to go to basic economics to understand what may be happening. While the evidence is limited, there is clearly changes in market dynamics which provide a rational for the wild inventory discrepancies.
There has been a substition effect between corn and wheat by livestock operators. When corn is more expensive than wheat, which usually sells at a premium, there will be a switch. The result is then an excess inventory of "found" corn. The issue is to what degree this substitution occurs.
Always follow the money and the incentives.