Corn and soybeans edged higher after closing almost unchanged on Tuesday.
The most-active wheat contract on the Chicago Board of Trade fell 0.3 percent to $4.58-1/4 a bushel by 0255 GMT, corn gained 0.3 percent at $3.61 a bushel and soybeans were up 0.2 percent at $9.00-1/2 a bushel.
The five days of losses for the wheat contract are the worst streak of declines since prices fell for six days in a row from Feb. 25 to March 4.
The wheat market is under pressure after the US Department of Agriculture (USDA) in a monthly report on Tuesday raised its forecast of global 2018/19 wheat ending stocks to 275.61 million tonnes, topping the highest in a range of trade expectations.
"The USDA cut their forecast of US exports for season 2018," said Tobin Gorey, director of agricultural strategy at Commonwealth Bank of Australia. "The wheat that was not exported is largely forecast to end up in inventories."
The agency raised its outlook for how much corn will be left in grain elevators ahead of harvest this year due to falling demand from the export, feed and residual and ethanol sectors.
The USDA also boosted its estimate of domestic wheat supplies. But it trimmed its outlook for soybean stocks for the third report in a row.
The USDA in a weekly crop progress report late on Monday rated 60 percent of the US winter wheat crop in good to excellent condition, up from 56 percent a week earlier, a sign of improving yield prospects. Analysts on average had expected no change in weekly ratings.
A spring snowstorm was forecast to cross parts of Nebraska, South Dakota, Minnesota and Wisconsin starting Wednesday, potentially dumping 8 to 16 inches of snow, the Commodity Weather Group said in a client note. Farmers in those areas are trying to prepare fields for the seeding of spring crops including corn.
Commodity funds were net sellers of CBOT wheat and soybean futures contracts on Tuesday and net buyers of soyoil, traders said.