Chicago grain futures slump, CBOT corn down over 3% on raised USDA output, supply outlook

The move reflects a straightforward supply-side repricing: the USDA's own monthly report raised output and supply expectations, and futures adjusted accordingly. The signal matters less for the size of the drop than for the direction of the revision, since it shifts the balance-sheet narrative that grain traders anchor to between reports. Whether the higher supply outlook is sustained in subsequent revisions, or offset by demand-side adjustments, is the open question for corn and the wider Chicago complex.