The Board shall retain the right to determine eligibility of lenders and holders of education loans to which payments may be made. An eligible lender or holder shall, in general, make or hold education loans made to individuals for purposes of undergraduate and graduate education and shall not be any private individual. An eligible lender or holder may be, but is not limited to, a bank, savings and loan association, credit union, institution of higher education, secondary market, governmental agency, pension fund, private foundation, or insurance company.