The Nebraska Investment Council, out of funds available to it, upon the application of any qualified lending agent as defined under the Federal Higher Education Act of 1965, may purchase all student loans which are federally guaranteed, as to principal and interest, and made to Nebraska residents attending Nebraska institutions, which are offered to the Nebraska Investment Council for purchase and shall give preference to such loans when an investment in such loans would be equally as good as any other investment; Provided, such offers shall be in amounts of five thousand dollars or more from a single lending agent.