Because grain traders had expected the Soviet purchases, Chicago corn prices have only recently gained from the sales, they said.

Corn futures prices, meanwhile, rallied on rumors of new Soviet purchases while soybeans were mixed.

The United States has offered as much as $1 billion in credit guarantees for Soviet purchases of food.

Occasional shortfalls of Soviet purchases under the current agreement have been largely made up eventually, though informally, specialists said.

With the latest sale, Soviet purchases in the past two weeks total 2.95 million metric tons.

It calls for minimum annual Soviet purchases of nine million metric tons of grain and oilseeds.

Big harvests and fewer Soviet purchases are helping to deflate prices.

Soviet purchases last year were about $700 million.

The Administration is nearing a decision whether to guarantee $1.5 billion in additional commercial bank loans for Soviet purchases of American grain.

Soviet purchases of United States corn totaling 4 million tons were announced last week alone.