Supplies were tightening seasonally at some processors and river terminals as some dealers boosted their basis bids in efforts to entice farmers to deliver old-crop stocks before the harvest in about a month.
Corn bids gained by 7 cents per bushel at a closely watched processor in Decatur, Illinois, and edged 2 cents higher at a processor in Cedar Rapids, Iowa. Soybean bids climbed 5 cents at a processor in Council Bluffs, Iowa.
Bids for both commodities had a firm tone at terminals along the Mississippi and Illinois rivers.
US Department of Agriculture data showed weekly US soybean export inspections for the week ended Aug. 3 were better-than-expected at 685,697 tonnes and the agency also said exporters sold 206,000 tonnes of soybeans to unknown destinations within the past 24 hours.