Any guarantee of a loan prepaid under this section shall be fully assignable under the provisions of section
936 of this title and transferable. However, the Secretary may require that any such guarantee, if transfered or assigned, be transferred or assigned to a loan or security that, if sold, will be grouped with nonguaranteed loans or securities and sold in a manner to ensure that such sale will not unreasonably compete with the marketing of obligations of the United States.