CHICAGO (Dow Jones)--U.S. corn futures are expected to open lower Thursday as traders take profits following strong gains Wednesday.

Traders expect Chicago Board of Trade futures will open 2 to 4 cents lower. In overnight trade, corn for December delivery was down 3 1/2 cents, or 0.6%, to $5.48 1/4 per bushel. March corn, the most active contract, was down 3 1/4 cents to $5.63.

Traders are expected to take profits after a 3.8% rally on Wednesday, analysts said. That rally was fueled by higher wheat prices and fund-buying to start the month. Speculative funds often push the market higher at the beginning of the month, said Don Roose, president of U.S. Commodities in West Des Moines.

"They raise money during the month, and then they put it to work at the beginning of the (next) month," Roose said.

The market closed above its 50-day moving average for the first time since Nov. 18. But there was little fundamental reason for such a strong climb Wednesday, traders said.

Weekly export sales Thursday were in line with trader expectations. The U.S. Department of Agriculture reported weekly net sales of 758,100 metric tons, down 8% from the prior week but up 27% from the prior four-week average. Analysts were expecting between 500,000 and 900,000 metric tons.

U.S. ethanol policy is a background concern that has weighed on the market recently. Congress has until the end of the year to renew the 45-cent-per-gallon ethanol blenders credit. Some traders are worried that the credit could expire, although most expect it to be renewed at a lower rate of around 36 cents.

Roose said that such a reduction would have just a "minor" impact on the ethanol industry and corn demand.

Losses could be limited by the USDA's announcement of two fresh sales Thursday morning: 135,128 metric tons to Japan for the 2011-12 marketing year and 238,000 to unknown destinations for 2010-11.

Wheat prices could also continue to underpin the market, as that market continued to gain in overnight trade. It has surged in recent days on worries about a soggy Australian harvest and dry weather in the U.S. Plains that is prompting concern about the winter wheat crop.

-By Ian Berry, Dow Jones Newswires; 312-750-4072;