USDA's November WASDE tripled China's 2018/19 corn ending stocks to 207.5 MMT while cutting U.S. corn yield by 1.8 bushels per acre to 178.9, reducing U.S. production by 3.861 MMT to 371.52 MMT. December corn futures rose 1.8% for the week despite the China revision.
The smaller U.S. crop and lower export forecast are bullish for corn prices, though the large Chinese stock increase partly offset that effect. Buyers should expect firm corn values if the U.S. supply tightening holds.
Not enough comparable past events yet for a historical read.
After 1,040 past bullish report events, Corn moved a median +0.5% over 5 sessions (62% higher; middle half -0.9% to +2.0%), and +0.8% over 20.
Moves of each commodity's benchmark from the last close before the event. Historical reads pool past events of the same kind; they describe what happened, not what will. Not investment advice.