Why are US Corn Futures falling 3% today?

US Corn Futures experienced a 3.5% decline during mid-day trading after the USDA released its Quarterly Grain Stocks report. The final stocks figures for the 2025-26 marketing year showed corn inventories at 1.918 billion bushels, exceeding market expectations. This surplus signaled ample supply, causing December corn futures to drop from their opening level near 522 to a session low of 503.38.

The report revealed that all six headline supply numbers had come in above estimates, meaning the market had been positioned for a tighter report than it received. The USDA Crop Progress report indicated that corn was only 18% harvested, behind trade expectations. China's decision to exclude soybeans from tariff cuts, while US beans continued to carry an extra duty, added uncertainty to the demand outlook.

The broader equity market remained positive, with the S&P 500 and NASDAQ gaining, highlighting that today's corn weakness was commodity-specific. The USDA Grain Stocks report was the key variable, and a larger-than-expected corn inventory was seen as the scenario most likely to hit corn futures hardest. The combination of the stocks data and month and quarter-end flows amplified selling pressure into the close.