USDA's September Grain Stocks report put Sept. 1 corn stocks at 2.095 billion bushels — a 35% year-over-year increase and substantially more old-crop supply than traders anticipated. Corn futures quickly fell below the psychological $5 mark. According to Andrew McCarty, founder and president of Pluto Commodities, the surprise did not come from a bigger crop; USDA actually cut last year's production by roughly 58 million bushels. The extra supply surfaced through weaker implied feed and residual demand, adding carry-in with roughly the same impact as an additional 2 bushels per acre on the 2026 crop.

"The focus now shifts directly to harvest yields and demand," McCarty said. "Corn needs either a smaller 2026 crop or stronger demand to absorb this additional supply, making October's production update increasingly important." He noted that soybeans remain focused on harvest yields and China, while wheat's balance sheet changed little. His advice: have risk-management plans in place before the surprise arrives, and watch basis and futures spreads closely, particularly with on-farm storage.

Joshua Strine of Purdue University's agricultural economics department points out that futures absorbed the stocks shock quickly, but the effect on basis is usually more modest because local buyers already know what sits in their storage. Producers in Indiana, Ohio, Illinois and Iowa can track local corn and soybean basis through the Purdue Crop Basis Tool. Strine reports that soybean processor basis in Iowa and Ohio is at its strongest level for this time of year since 2014. Even so, history suggests basis will weaken over the next month. Harvest is behind schedule in several states, particularly across the Eastern Corn Belt after persistent rainfall since late summer; drier weather should accelerate picking, and that influx of local supply can pressure basis. His recommendation: for unpriced corn without storage, lock in basis now to limit downside from seasonal weakness that often runs through mid-October, and shop for the best bids.

Chris Swift, founder of Swift Trading Company, sees the 35% year-over-year stocks increase as having "dampened a lot of bull's spirits," but with that large a miss, the figure could be revised later. Military actions disrupting production and movement worldwide keep a firm tone under grains and oilseeds. He also flags energy-market volatility: the longer grains and oilseeds stay elevated as energy components, the more renewable-fuel usage the market should anticipate. His action point: the carry in corn rewards storage, and farmers should pencil out how many pre-sold bushels to re-own as call options.

Jon Scheve, adviser and owner of Scheve Grain, reads the report as neutral for soybeans. "$13 soybeans are certainly a very fair value and still could go up, depending what happens with U.S.-China trade relations, South America and other factors," he said, seeing beans range-bound between $12.50 and $13.50. On corn: "Have we seen the bottom yet? Probably not, but we're close. We're around that $5 psychological level. Are we going to test sub-$4.90? Maybe, but we're not going to $4.50." He believes the market is setting a new floor for the next six to 12 months, and advises farmers who haven't made sales to focus first on getting the crop out of the field.

Matthew Giarelli, director of structured products at Hedgepoint Global Markets, frames October as the deciding month. Corn has retreated about 20 cents in the past week and a half of September yet still sits roughly 50 cents higher than 2024 and 2025 did going into harvest. In 2024, bumper crops, rapid harvest and improving South American weather pushed corn and soybeans lower by month-end. In 2025, harvest delays below the five-year-average pace, energy-market rallies and stronger crush demand lifted prices meaningfully. So far in 2026, harvest progress sits at the five-year average and extended-forecast rain is lightening — a bearish setup — while institutional funds have shifted from net shorts to net longs, the potential bullish driver. His action: market a small percentage of the 2027 crop above expected cost of production using premium, specialty or hedge-to-arrive contracts.

Beyond the balance sheet, input costs and weather loom. Dinese Watson, senior vice president of ag lending at Merchants Bank, notes diesel fuel has reached a record high during harvest, on top of unexpected equipment repairs. She urges farmers to communicate with lenders early when cash flow tightens rather than waiting for a problem.

Gabrielle Bourret-Sicotte, head of customer solutions at Treefera, warns a potentially historic El Niño is developing. Treefera's models project about 3.24 degrees C of ocean warming, roughly a full degree above the 2.27 degrees C seen in 2015, with about 95% confidence in that scenario — what she calls a "Godzilla" level event. Wetter conditions could hit California, the Southern Plains, Peru and Argentina, with flash-flooding risk. Central and northern Brazil and parts of Asia face the greatest acute climate-shock risk. Australia and Indonesia could see drought and wildfire affecting wheat, palm oil and Vietnamese robusta coffee, while weaker Indian monsoons could pressure sugar, rice, cotton and soybean production.

Naomi Blohm, senior market adviser at Total Farm Marketing, recommends setting cash price targets with elevators and ethanol plants now, since rallies can appear off a headline and vanish in 10 or 15 minutes. She also advises automating basis notifications, since quick basis plays can capture an extra nickel per bushel depending on local harvest inflows and demand.

With October's USDA production update next in view, traders will be watching whether harvest yields and demand can absorb the added carry-in, and whether a record-strength El Niño disrupts production across multiple continents in the months ahead.