China bought more US soybeans just days ahead of a key leaders' summit, a sign of further progress toward Beijing's pledge to boost purchases of American farm goods. State-owned firms booked at least four cargoes — or about 260,000 tons — of US soybeans late last week, said traders with knowledge of the deals. The supplies are mainly for loading in December and January from the Pacific Northwest and US Gulf, they said, asking not to be named as they weren't authorized to talk to the media.