US corn and soybeans prices fall sharply after USDA stocks surprise

US corn outright prices fell sharply Sept. 30, tracking losses on the Chicago Board of Trade after the USDA Grains Stocks report was released, which showed higher corn stocks than expected.

Platts assessed October CIF New Orleans corn at $222.75/mt Sept. 30, down $7.95/mt from the previous assessment. November CIF New Orleans corn was assessed at $229.80/mt, down $8/mt, while December FOB Gulf corn was assessed at $236.52/mt, down $8.36/mt.

The US Department of Agriculture updated its Sept. 1 quarterly stocks report to 2.095 billion bushels of corn by the end of the 2025-26 marketing year (September-August), up from a preliminary 1.922 billion bushels from its preliminary report Sept. 11. The figure was above S&P Global Energy CERA's estimate of 1.907 billion bushels and the trade expectation of 1.911 billion-1.918 billion bushels.

"Corn stocks were the surprise, above the high end of trade estimate, weighing on the rest of the market," a trader source said.

The CBOT December (Z) futures contracts lost 21.25 cents during the business day to $5.0075/bu.

The USDA reported that 787 million bushels of corn were held on-farm, while 1.31 billion bushels were stored off-farm. June-August 2026 corn disappearance was estimated at 3.20 billion bushels, up from 3.10 billion bushels during the same period a year earlier.

However, the increase in stocks was attributed in part to lower-than-expected feed and residual use, despite a downward revision to production.

"The USDA found lower corn production because the harvested area was smaller, but it also found lower feed and residual consumption," a broker source said.

The USDA cut its estimate of the 2025 US corn crop by 58 million bushels to 16.963 billion bushels. Planted and harvested areas were revised downward, while the yield estimate remained unchanged at 186.5 bushels/acre.

The bearish corn report also pressured soybeans, according to market participants.

"The market wasn't expecting that on corn. Eventually, they took beans lower with it because of the meal as well," a trader at a crusher said.

For soybeans, the report showed 315 million bushels of old-crop soybean stocks in all positions on Sept. 1, which fell at the lower end of market estimates but was not enough to have a significant impact, sources say.

The amount was "down 3% from Sept. 1, 2025. Of the total, 90.4 million bu are stored on-farm and 225 million bu were stored off-farm," the document said.

"Soybean stocks were slightly lower than expected, but corn's were significantly higher, that's really driving the markets today," crop principal analyst at S&P Global Energy Aaron Gerdts said. "Corn is pulling [soybeans] lower, though soybeans were on the lower side of the range. Residual use will end up being slightly higher."

The CBOT November (X) soybeans futures contract dropped 4.75 cents to 1293 cents/bu, while the January (F) contract fell 3.5 cents to 1309.25 cents/bu.

Platts, part of S&P Global Energy.