(Updates U.S. market activity to close, adds comments; changes byline, dateline, previous SINGAPORE/PARIS)
CHICAGO, Jan 10 (Reuters) - U.S. soybean futures slid to a four-month low on Wednesday, declining for the third straight session on expectations of higher U.S. stocks due to slower exports and a forecast of increased production in Brazil.
Wheat futures were slightly higher and corn flat as investors squared positions ahead of the U.S. Department of Agriculture's monthly supply and demand data due on Friday.
"We're anticipating some bearish (soybean) data - a cut in export demand and increasing in ending stocks. That's really driving it," said Price Futures Group analyst Jack Scoville.
Chicago Board of Trade March soybeans settled 8-3/4 cents lower at $9.55 per bushel, lowest since Aug. 31.
Analysts polled by Reuters expected the USDA to boost U.S. soybean stocks after a record-large harvest at the end of last year and slowing exports due to quality issues.
Meanwhile, Brazil's 2017-18 soybean crop is expected to be 111.8 million tonnes, 1.9 percent higher from the previous estimate, Céleres consultancy said on Tuesday.
"There are abundant soybean supplies and the new Brazilian crop forecast will add more pressure on prices," said one Singapore-based trader, despite some market concerns about the impact of adverse weather in Argentina.
CBOT March wheat finished up 2 cents at $4.34-1/4 per bushel, rising for the second consecutive day on technical buying. CBOT March corn was unchanged at $3.49.
The USDA is expected to show smaller U.S. winter wheat seedings, in the agency's first forecast for 2018.
Russian wheat continues to pose stiff competition in the well-supplied global market but supportive news came from other major Black Sea grain producer Ukraine where exports are running behind last season with 11.4 million tonnes of wheat exported since July, down from 12 million tonnes at the same point last year, the agriculture ministry said on Wednesday.
Farming agency FranceAgriMer lowered its forecast for French soft wheat exports outside the European Union this season for a third straight month on Wednesday, predicting 9.3 million tonnes versus 9.5 million last month. (Additional reporting by Naveen Thukraln in Singapore and Sybille de La Hamaide in Paris; Editing by Tom Brown)