Talk about unexpected.
The US Department of Agriculture shocked investors by sticking by an estimate of domestic corn stocks of 675m bushels for the end of 2010-11. This despite revealing last week that inventories were, half way through the season, 170m bushels short of expectations.
And markets came up with their own surprise by, after initial cogitation, apparently ignoring the data, in the USDA's flagship Wasde report.
Benson Quinn Commodities called the Wasde "a head scratcher", which was one of the more polite criticisms.
Mike Mawdsley at Market 1 likened the credibility of the data to believing "that we all love eachother and we are for world peace.
"It this report was true, then corn would be limit down," he added.
As it was, corn, after an initial dip, closed up 1.2% at 7.68 a bushel for May delivery. Indeed, funds bought an estimated 13,000 lots.
To be fair, that wasn't only down to dismissal of USDA analysis. External markets came in with a positive signal in terms of the fall in the dollar to a 15-month low against a basket of currencies, as investors switched to the euro, where interest rates on the rise.
Opinion of the dollar was further mired by concerns that last-minute Washington budget talks might fail. A weaker greenback makes dollar-denominated assets more affordable.
Meanwhile, oil was strong too, helping the case for crops, such as corn, used in making biofuels.
"Oil above $111 a barrel is certainly not negative to corn," Darrell Holaday at Country Futures said.
Growing fears for inflation indeed boosted many commodities, including copper, which ended up more than 2% in London, enjoying its best week for four months.
But taking, shall we say, a different view of the USDA report than the obvious one was a big factor.
And corn's ability to overcome an apparent setback gave other crops the confidence to rise too – by the maximum allowed by the Chicago exchange in
That was the scenario that the USDA portrayed in sticking by its year-end corn stocks estimate. And, indeed, for once Chicago outperformed its peers with Minneapolis spring wheat for May ending up 1.2% at $9.61 ½ a bushel, while Kansas wheat finished 1.1% up at $9.32 ¾ a bushel.
Furthermore, Chicago wheat gained technical assistance after breaking back above its 100-day moving average line.
May soybeans closed up 2.1% at $13.92 ¼ a bushel.
"What is unusual for me is to see that in cotton the May futures still had over 70,000 in open interest as of yesterday," despite expiry not too far away.
"This past week's volatile market showed just how dangerous and unpredictable the old crop is," Jurgens Bauer at PitGuru said.
Old crop May cotton ended down 2.5% at 202.97 cents a pound in New York.
Sugar was down even further, falling 3.2% to 25.66 cents a pound for May delivery on a decline blamed in part on technical factors, with a roll into later contracts going on, and the lot breaking down through the key 26-cents-a-pound mark.
Fundamentally, promising production prospects for "Brazil and Thailand in particular give the bears the upper hand", Thomas Kujawa at Sucden said.
"It still seems safer to sell a rally than buy a dip."
In fact, even grains were mixed in Europe, with Paris wheat closing down 1.0% at E247.25 cents a pound for May, a reflecting of the stronger euro and with the best of the rally in Chicago wheat coming towards the close after European markets were finished.
London wheat ended up 1.0 % at £206.75 a tonne, with co-operative Openfield saying UK grain "looks good value in the intra-European Union grains matrix"
Furthermore, the "hot dry weather - a new daytime high for April - is a talking point".