U.S. grain markets moved sharply lower on Wednesday, September 23, with corn and winter wheat futures losing about 1.25% and soybeans falling roughly 0.5%, as technical selling and harvest pressure collided with uncertainty over export demand and U.S.-China trade. The decline matters directly to American farmers because it comes during the heart of harvest, when large volumes are moving into the supply chain and weaker futures can quickly affect cash bids, basis levels, storage decisions and farm margins. December corn settled at $5.29 per bushel, while November soybeans closed at $13.18.

Selling accelerated even as the market received a fresh export signal from Mexico. Private exporters reported 3.9 million bushels of U.S. corn sold to Mexico for delivery during the 2026/27 marketing year, according to the market information reviewed by Agrolatam. Still, that business was not enough to reverse the bearish tone. December corn dropped 7.75 cents to $5.29 per bushel, while March futures fell 7.5 cents to $5.4350. For growers, the session illustrated an important challenge: strong individual export sales can be overshadowed when harvest supplies and technical selling dominate price discovery.

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Chicago grain futures - September 23

Harvest Pressure Meets a High-Stakes Export Market

Domestic demand also provided traders with another reason for caution. U.S. ethanol production averaged 1.028 million barrels per day during the week through September 18, the lowest weekly level since early May, while ethanol inventories declined 2%, according to Energy Information Administration figures contained in the market data reviewed by Agrolatam. The EIA directly tracks weekly U.S. petroleum and ethanol supply statistics. For corn producers, ethanol remains a critical component of domestic demand, making sustained changes in plant output important for local basis, grain movement and overall commodity prices.

Soybeans also finished in negative territory despite some late-session technical buying. November and January futures each lost 7.5 cents, settling at $13.18 and $13.3375 per bushel, respectively. Soymeal December futures slipped 0.03%, while December soybean oil declined 0.16%. Traders are closely watching the next signals from U.S.-China trade relations because export expectations can materially change the balance sheet for the oilseed complex. During harvest, that uncertainty adds another variable for farmers deciding whether to sell directly, establish futures or options coverage, or store soybeans in anticipation of stronger basis or futures values later in the marketing year.

Export demand now becomes an important test. Ahead of the USDA's next weekly report, market expectations cited in the supplied data ranged from 31.5 million to 55.1 million bushels of corn sales, 55.1 million to 73.5 million bushels of soybeans and 12.9 million to 22 million bushels of wheat for the week ending September 17. USDA's Foreign Agricultural Service publishes the Weekly Export Sales report covering corn, soybeans, wheat, soybean meal and other agricultural commodities, providing the market with a direct gauge of overseas demand.

Export sales expectations

Wheat followed corn lower as technical selling and profit-taking pressured the market. December Chicago SRW wheat lost 8.75 cents to $7.0850 per bushel, while December Kansas City HRW fell 9.5 cents to $7.7175. Yet the international supply picture remains mixed. The supplied market data put projected EU and UK wheat production at 5.053 billion bushels, down 2.3% from the previous estimate, following hot and dry conditions in parts of Europe. Argentina's wheat crop, meanwhile, was projected at 859.8 million bushels, below the prior season's 1.021 billion bushels. Those developments could influence export competition for U.S. wheat.

Argentina crop outlook

Weather could temporarily complicate the supply side. Forecast information points to additional precipitation across portions of the Plains and central United States, potentially slowing fieldwork as harvest advances. NOAA's Weather Prediction Center had active precipitation forecasts for September 23-27 and highlighted excessive-rainfall risks across parts of the Plains. For farmers, harvest delays are not automatically bullish: rain can slow the arrival of grain, but prolonged wet conditions can also increase drying requirements, field losses and operating costs while disrupting elevators, transportation and the broader supply chain.

For U.S. agriculture, the next price signal will come from the interaction of several forces rather than a single headline. Harvest pressure is increasing physical supplies, ethanol production has weakened, and grain markets are looking for evidence that exports can absorb available bushels. USDA export data, weather across the Corn Belt and Plains, and developments in U.S.-China agricultural trade will therefore remain central for corn, soybean and wheat prices. With input costs and farm profitability still critical considerations, another period of volatility would put marketing plans, crop insurance strategies and on-farm storage decisions back in focus.