The front-month contract peaked at $15.22-3/4 a bushel, its highest on a continuous basis since hitting $15.26-1/4 on July 23.
The May contract, hit a fresh high on Wednesday and closed above the high end of its 20-day Bollinger range for the first time since April 1.
Traders noted more bull spreading, with the July contract gaining another 12-3/4 cents on new-crop November. Supplies were expected to remain thin in the United States until farmers begin harvesting this fall, which will likely flood processors and elevators with the oilseed.
Soymeal futures also rose, with the tightening up of crushing supplies expected to reduce the amount of soymeal available for sale on the marketplace. Dealers reported weak end user demand, which kept Wednesday's gains in check.
Soyoil futures rose on spillover strength from soybeans and soymeal.
Bids for soybeans were steady to firm on the domestic cash market due to slow farmer sales. CIF bids for soybeans jumped to a two-week high due to the tight supplies.
Analysts were expecting a US Agriculture Department report on Thursday morning to show that old-crop export sales of soybeans were in a range from -100,000 to 100,000 tonnes in the latest reporting week. A week ago, old-crop soybean export sales 79,200 tonnes.
New-crop soybean export sales were seen in a range from 175,000 to 350,000 tonnes compared to 210,400 tonnes last week.