December corn settled at $5.29 per bushel on September 23, shedding 7.75 cents as technical selling, harvest pressure and softening ethanol output pulled the Chicago futures complex lower during the heart of the U.S. harvest.

November soybeans closed at $13.18 per bushel, down 7.5 cents. January soybeans slipped the same 7.5 cents to $13.3375. December Chicago soft red winter wheat fell 8.75 cents to $7.0850, and December Kansas City hard red winter dropped 9.5 cents to $7.7175. The session knocked corn roughly 1.25%, soybeans about 0.5% and added to a multi-week slide that is starting to bite at the farm-gate level.

What did the export book show?

Private exporters reported 3.9 million bushels of U.S. corn sold to Mexico for delivery in the 2026/27 marketing year. Mexico remains the top foreign buyer of U.S. corn, and the sale confirmed demand at the margin. Still, the business could not offset the supply-side weight. With combines rolling across the Corn Belt, elevators are filling, basis is tightening in many regions, and futures are absorbing the harvest pressure.

Why did ethanol matter?

U.S. ethanol production averaged 1.028 million barrels per day for the week ending September 18, the lowest weekly rate since early May, according to Energy Information Administration data. Ethanol stocks fell 2% over the same week. Because ethanol plants consume roughly 40% of U.S. corn, the production slip removes a key demand cushion and pressures local basis around plants in Iowa, Nebraska, Illinois and Indiana.

How big is the export test?

Traders await the U.S. Department of Agriculture's Foreign Agricultural Service Weekly Export Sales report covering the week ending September 17. Pre-report expectations called for:

• Corn: 31.5 million to 55.1 million bushels
• Soybeans: 55.1 million to 73.5 million bushels
• Wheat: 12.9 million to 22.0 million bushels

USDA publishes the report on corn, soybeans, wheat and soybean meal, giving the trade a direct read on overseas demand at a moment when China remains the swing factor. U.S.-China trade uncertainty is weighing on soybean balance sheets. Farmers holding unpriced soybeans must choose between selling into weak basis, hedging with futures, or storing into a possible post-harvest rally.

What is the global wheat picture telling U.S. growers?

December Kansas City HRW fell 9.5 cents to $7.7175 on technical selling and profit-taking. International supply signals remain mixed. Trade data project EU and UK wheat production at 5.053 billion bushels, down 2.3% from the prior estimate after hot, dry conditions in parts of Europe. Traders project Argentina's wheat crop at 859.8 million bushels, down from 1.021 billion last season. Forecasts put Argentine corn at 2.598 billion bushels (+3.1%) and soybeans at 1.969 billion bushels (+7.0%).

Smaller overseas crops can tighten export competition for U.S. wheat, but only if logistics, currency and quality align. Until then, Chicago futures set the most visible price for Kansas, Oklahoma and Texas elevators.

Will weather change the math?

NOAA's Weather Prediction Center flagged active precipitation across the Plains and central U.S. for September 23-27, with excessive-rainfall risks in parts of the Plains. For farmers, harvest delays are not automatically bullish. Wet conditions slow grain arrival at elevators, lift drying costs, and can raise field losses in continuous corn and late-planted soybeans. Wet weather can also disrupt rail and barge movement tied to Gulf and Pacific Northwest export terminals.

What signals come next?

Three forces will frame the next move: rising harvest deliveries, ethanol run rates, and export evidence. Pre-report estimates put corn export sales at 31.5 to 55.1 million bushels for the week ending September 17; a print below the low end would extend the slide. A strong number paired with a constructive trade headline could pull December corn back toward $5.40-$5.50. The bigger test arrives Oct. 9, when USDA's World Agricultural Supply and Demand Estimates report confirms whether the carryout is heavier than expected.