Chicago Board of Trade soyabean futures weakened amid technical selling on Wednesday, with the most-active contract dropping to its lowest price since September, traders said.
Beneficial rains for crops in Brazil and Argentina added pressure on futures prices, according to traders, because South America is a competitor for export business.
Rainfall is expected to increase across Brazil over the next week, leading to major improvements in soil moisture across northern and central growing areas, according to weather firm Maxar.
Traders are also watching for developments in attempts to reach an initial trade deal with China, the world's top soyabean importer. The US Department of Agriculture is due to issue weekly export sales data on Friday, one day later than normal because of Thanksgiving on Thursday.