Hard and soft red winter wheat basis offers were steady, supported by slow farmer selling, traders said.
There was talk that Iraq would seek to buy an unspecified amount of wheat, possibly announcing a tender as early as Thursday.
"It would not be inconsistent with what they have been saying," a trader said, referring to Iraq's intention to buy 1 million tonnes of wheat every month through December.
USDA last week confirmed the sale of 800,000 tonnes of US wheat to Iraq. A senior Iraqi official said last month that Iraq would buy a total of 1 million tonnes in October.
Traders said HRW wheat basis values were supported by demand from Nigeria. They said there had also been an increase in demand for spring wheat from Philippines and Europe.
Soyabean basis offers were firm, supported by export demand, traders said.
One trader said China is believed to have bought at least 5 US cargoes so far this week, mostly for late November and early December shipment.
"There has been stepped up demand from China despite the bird flu situation there," he added.
China has been battling the spread of the deadly disease, which has killed 64 people in Asia.
Corn basis offers were mostly steady, but export demand was sluggish, traders said, adding that some importers were holding out for Thursday's USDA crop production and stock reports.