Corn futures extended losses which have dragged them some 15% below August's record high after the US revealed that its total exports of the grain last week would have filled but a few farm trailer loads.

US corn export sales in the week to last Thursday slumped to 0.5% of their level the previous week, a figure itself considered poor.

"Corn sales were dismal at 400 tons. Yes, 400 tons - that is not a typo", Benson Quinn Commodities said in a note.

In fact, the figure was 368 tonnes, down from nearly 790,000 tonnes in the same week last year.

'Record poor' 

Indeed, according to broker US Commodities the sales were "record poor on corn for this time of year", and stoked ideas that even after a price slide of well over $1 a bushel, US supplies are being undercut on global markets by Brazilian supplies.

"US corn is not competitive in the world markets. It is overvalued by $1.25 a bushel versus South American corn," the broker said.

The gap has become such it has, unusually, become worth some US consumers importing, rather than using domestic supplies of a crop of which America is by far the largest producer.

East coast US livestock groups including Prestage Farmers have signed deals to import 750,000 tonnes of corn, the hog producer said on Wednesday.

Price impact 

The impact in Chicago was to send corn for December delivery down to $7.11 ¾ a bushel at one point, a decline of 1.8% on the day, and the lowest for a benchmark contract since early July.

Wheat futures were also soft, dropping 2.3% to $8.49 ¼ a bushel, dragged lower by their fellow grain. US wheat export sales of 426,000 tonnes were towards the lower end of market expectations.

However, soybeans for November recovered losses to get back into positive ground, up 0.75 cents at $15.73 ¾ a bushel with an hour or so of trading to go in Chicago.

Soybean weekly export sales of nearly 800,000 tonnes beat forecasts, and with a further sale of 110,000 tonnes announced through the US Department of Agriculture's daily alerts system.

Soymeal sales, at 424,700 tonnes, were "stellar", Benson Quinn said.