Bonds issued under the provisions of this chapter and purchased by the Board of Trustees of the Virginia Retirement System shall be deemed negotiable instruments under the laws of this Commonwealth. The Board of Trustees may, in its discretion, sell any such bonds so purchased and held by it at such time or times as to it may seem desirable in the management of the funds under its control; and such bonds are hereby made securities in which all public officers and bodies of this Commonwealth, and all counties, cities and towns and municipal subdivisions, all insurance companies and associations, all savings banks and savings institutions, including savings and loan associations, trust companies, beneficial and benevolent associations, administrators, guardians, executors, trustees and other fiduciaries in this Commonwealth may properly and legally invest funds under their control.