Corn prices are heading for their longest losing streak since June, putting pressure on hedge funds after money managers built their most bullish net position in the crop on record, according to a report by Bloomberg.

The most-active Chicago corn futures contract fell as much as 1.1% on Wednesday, extending declines into a fifth consecutive session. The retreat comes less than a week after prices reached their highest level in three years.

Commodity funds held a record net-long corn position as of 1 September, according to 20 years of Commodity Futures Trading Commission data. Hedge funds had increased their bullish exposure amid concerns that adverse US weather could weigh on yields, while disruptions to crop shipments from the Black Sea added to supply concerns.

The scale of the positioning could now leave funds vulnerable if the rally continues to unwind. Corn’s 14-day relative strength index recently moved above 70, a level commonly viewed as indicating overbought conditions.

The next major test for the market will come on Friday, when the US Department of Agriculture releases its latest World Agricultural Supply and Demand Estimates. Analysts surveyed by Bloomberg expect the USDA to reduce its forecasts for both global and US corn inventories for the 2026-27 season.

At the same time, the US harvest is beginning to accelerate. Farmers had harvested 5% of the corn crop by 6 September, ahead of the pace recorded at the same point last year, according to USDA data.

The arrival of additional physical supply could create further headwinds for futures, particularly if the USDA's latest estimates fail to reinforce the bullish case underpinning hedge funds’ record positioning.