A Census, Not a Model
Most USDA numbers are estimates built from surveys and models. Grain Stocks is different: NASS surveys thousands of farmers and commercial storage operators to count physical bushels as of the first of the month — December 1, March 1, June 1, and September 1. The report breaks stocks into on-farm and off-farm positions, which itself tells a story about who is holding the crop and how willingly they are selling.
Because it counts what actually exists, the report also exposes errors in earlier assumptions. When stocks come in far below the implied pace, the market learns that feed use, exports, or the crop size itself was misjudged. The survey covers the major program crops — corn, soybeans, all wheat, sorghum, oats, barley, rye, and others — and the state-level breakdowns matter to basis watchers in the big producing states, even though the futures trade keys on the national totals.
The Dates and the Combos
- End of March — March 1 stocks, released the same day as Prospective Plantings. Routinely the most violent grain day of the spring.
- End of June — June 1 stocks alongside the Acreage report. Another double event.
- End of September — September 1 stocks, the old-crop final count for corn and soybeans, and it revises the previous crop's balance sheet.
- Mid-January — December 1 stocks, released with the annual Crop Production summary that finalizes the harvested crop.
All four release at 12:00 p.m. Eastern, and grain futures trade straight through the number without a halt, which is why the first minute can be chaotic.
How Traders Use It
Analysts back into an expected stocks figure from known usage — exports, ethanol grind, feed estimates — so the pre-report trade estimate represents the market's working theory. A stocks number far below the range implies usage was underestimated; far above implies demand is weaker or the crop was bigger than counted.
Practical note: the September report can revise old-crop ending stocks months after the fact, and the market shrugs at history while repricing the new-crop implications. Hedgers holding unpriced old crop into a stocks report are carrying genuine event risk. Futures trading involves substantial risk of loss and is not suitable for all investors.