Bears returned to control in Chicago in early deals, but only just, as investors braced for the start of a barrage of data.

The slew of statistics starts later on Wednesday when Conab, the Brazilian crop bureau, unveils its latest crop estimates, amid improving ideas for corn and soybean crops in the country, and in neighbouring Argentina too.

Then Thursday brings Chinese trade data, at which traders will be looking particularly closely for any signs of a slowdown in imports of soybeans, of which it is the top buyer.

RJ O'Brien noted that it was "picking up a wide range of estimates" for Chinese soybean imports last month, with estimates ranging from 3.3m-5.5m tonnes.

'Additional upward potential'

Thursday also brings official data on Malaysian palm oil stocks expected, with production in seasonal decline, to show some fall from November's record high of 2.56m tonnes, but not much.

That  said, Kuala Lumpur palm oil, against its recent nature, edged higher on Wednesday, by 0.6% to 2,404 ringgit a tonne as of 09:40 UK time (03:40 Chicago time) helped by supportive comment from Oil World, the influential analysis group.

"Palm oil prices have additional upward potential in January-to-April as production in South East Asia will be declining seasonally, resulting in a production deficit and a decline in palm oil stocks," Oil World said.

Palm oil prices were "attractive" compared with those of rival vegetable oils, such as soyoil and rapeseed oil.

'Most-watched Wasde'

Then Friday brings the main event, the US Department of Agriculture's January Wasde world crop supply and demand report, with US inventory and winter wheat seeding statistics too.

The monthly Wasde briefings are, anyway, key events of the commodities calendar.

But the January briefing "is the most-watched Wasde report of the year" because of its issue of final estimates for US 2012 crops, Lynette Tan at Phillip Futures said.

"Trading is usually active and volatile following the report."

Chicago corn futures have moved the daily limit (usually downward) in five out of the last six years on January Wasde day.

Historical evidence

And investors in early deals proved reluctant to take too many risks ahead of the data wave.

OK, there is fair reason to take a bearish stance, given not only the improving ideas over South American harvests, but also the Wasde's record for guessing US stocks – the ultimate driver of prices.

"December 1 corn stocks have exceeded trade expectations in three of last four years," Richard Feltes at RJ O'Brien said, with soybeans coming in ahead of forecasts in three out of the last five years.

He added: "Note that the trade error in estimating December 1 row crop stocks for the January crop report has increased over the last six years in wake of larger production, a surge in farmer/commercial storage, and ever larger quantities of distillers' grains displacing corn and soymeal."

Brian Henry at Benson Quinn Commodities noted that "it appears the USDA has plenty of romm to lower their US corn export figure", after a poor start to 2012-13, when Brazil has been picking up trade.

'Fund selling exhausted?'

However, investors have already taken corn, soybean and wheat futures to six-month lows this month, near where they remain.

Indeed, "funds were estimated buyers of 3,000-4,000 corn contracts on Tuesday, which bolsters ideas that that the recent pattern of fund selling is perhaps being exhausted", Mr Henry said.

And not all the newsflow is going bears' way, with Chinese wheat prices going the opposite way to those in Chicago, rising more than 6% from a mid-November low, amid concerns over cold weather impacting crops, and ideas that last year's harvest was not nearly as strong as official data show.

(In fact, Zhengzhou wheat futures eased on Wednesday, dropping 0.3% to 2,601 yuan a tonne for May delivery.)

Black Sea worries

Meanwhile, there are concerns about frost damage to Black Sea crops too, with Ukraine's agro-meteorological service estimating that 12% of winter crops are in poor condition, compared with 7% at the start of last month.

In Crimea, in the south of Ukraine, the figure may be 40%.

"Crop conditions have recently been partially degraded by the cold wave that hit the country during December," consultancy Agritel said.

"At this stage, it is reasonable to assume that cultures in the Southern District of Russia," a major source of wheat for export, "suffered from the same cold wave.

"Indeed, the conditions experienced by the south west of Russia were relatively similar to those recorded in the Crimea - a fall drought associated with some negative temperatures and no snow cover."

'Story still lacking'

Still, suck talk has yet to capture the imagination of international markets.

"The story in the wheat market is still lacking," Benson Quinn's Mr Henry said.

Chicago wheat for March eased 0.3% to $7.48 ¼ a bushel, with the Kansas March lot (supposedly, unlike its Chicago peer, favoured by the index fund rebalancing) down 0.3% at $8.06 a bushel,

Chicago corn for March dropped 0.2% to $6.87 ½ a bushel, with March soybeans (set on Monday to become the spot contract with the expiry of the January lot) down 0.1% at $13.84 ¾ a bushel.

'Significant support'

Among soft commodities, New York cotton managed a little bit of a bounce from the 0.8% decline of the last session, with the March contract added 0.2% to 75.28 cents a pound.

"Nonetheless, a bearish USDA Wasde report this Friday could result in values heading back to their October/November lows of 70-72 cents a pound," Luke Mathews at Commonwealth Bank of Australia said.

He was slightly more upbeat on prospects for sugar futures at current levels half those seen in 2011.

"The market is now eyeing the December 13 close of 18.54 cents a pound, a level that we think would provide significant support," he said.

"Nonetheless, a breach of this support would open up the potential for more significant price declines."

'Technically vulnerable'

Phillip Futures' Lynette Tan was of a more bearish persuasion.

"The ICE raw sugar contract looks technically vulnerable to break below the current trading range to gravitate towards the 18-cents-a-pound levels," she said.

"However, slow producer selling may support prices in the very near term."

The March contract stood unchanged at 18.67 cents a pound.