* USDA expected to raise U.S. soy stocks outlook on Friday
* Wheat eases after smaller-than-expected U.S. export sales (Updates prices, adds comments; changes byline, dateline, previously PARIS/SINGAPORE)
CHICAGO, Jan 11 (Reuters) - Chicago soybean futures fell to a four-month low on Thursday ahead of U.S. Department of Agriculture data due on Friday that was expected to show bigger U.S. stockpiles and higher Brazilian soy output.
Wheat futures also eased after weekly U.S. wheat export sales came in below analyst expectations, while corn futures were nearly unchanged.
Trading ranges in each of the commodities were narrow in advance of the USDA crop data that also was likely to show smaller U.S. winter wheat plantings and a decline in U.S. corn ending stocks.
"Nearly all activity in today's trade is a result of positioning ahead of tomorrow's report," MaxYield Cooperative analyst Karl Setzer said in a client note.
CBOT March soybeans were down 4 cents to $9.51 per bushel as of 12:22 p.m. CST (1822 GMT), just above their earlier multimonth low of $9.50.
Agroconsult on Thursday said Brazil should harvest 114.1 million tonnes of soybeans in the 2017/18 crop season, which would match an all-time record set in 2016/17. The consultancy in November forecast a 111 million tonne harvest.
The big Brazilian crop was likely to dominate global export trade markets in the months to come, stealing away market share from U.S. soy exporters.
"It is difficult for U.S. soybean exports to recover now as Brazilian new-crop supplies will hit the market at the beginning of February," said one India-based agricultural commodities analyst at an international bank.
Weekly U.S. soybean export sales of 607,400 tonnes and corn sales of 437,800 tonnes were both within analyst estimates.
But U.S. wheat exports dropped to 71,500 tonnes, a marketing-season low and below estimates for 250,000 to 450,000 tonnes.
CBOT March wheat eased to a session low of $4.28-1/4 per bushel in the wake of the export data before paring losses to $4.33-1/2, down 3/4 cent.
CBOT March corn was down 1/4 cent to $3.48-1/4. (Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Tom Brown)