Chicago Board of Trade most-active corn fell 0.6pc to $3.62-3/4 a bushel at 1042 GMT, wheat was 0.6pc down at $5.41 a bushel. Soybeans edged up 0.05pc to $10.03 a bushel.
Soybeans fell 4.1% this week, their biggest weekly decline since mid-March, while corn's weekly loss of 3.6% was set to be its biggest.
Chicago Board of Trade November soybean futures ended up 2-1/2 cents at $10.02-1/2 a bushel. CBOT December corn was 1-3/4 cents higher at $3.65-1/4 a bushel.
The corn was bought at an estimated $227.49 a tonne c&f plus a $1.25 a tonne surcharge for additional port unloading Seller was believed to be trading house Olam.
The corn was purchased at an estimated $229.00 a tonne c&f for shipment from Brazil between Oct. 15 and Nov. 15. Seller was believed to be trading house Midstar.