TOKYO (Reuters) - Marubeni Corp, Japan's fifth-biggest trading house, said on Tuesday it would buy 100 percent of U.S. grain merchant Gavilon Holdings LLC for $3.6 billion.

Gavilon is the third-biggest U.S. grain merchant in terms of the size of its marketing network, behind Archer Daniels Midland and Cargill, and also has large energy and fertilizer trading assets.

Owners of Gavilon include hedge fund manager Dwight Anderson and billionaire investor George Soros.

(Reporting by Yuko Inoue; Editing by Michael Watson)