N.C. Gen. Stat. § 116-196
Any bonds issued under this Article shall at all times be exempt from all taxes or assessment, direct or indirect, general or special, whether imposed for the purpose of general revenue or otherwise, which are levied or assessed by the State or by any county, political subdivision, agency or other instrumentality of the State, excluding income taxes on the gain from the transfer of the bonds, and franchise taxes. The interest on the bonds is not subject to taxation as income. Bonds issued by the Board under the provisions of this Article are hereby made securities in which all public officers and public bodies of the State and its political subdivisions, all insurance companies, trust companies, banking associations, investment companies, executors, administrators, trustees and other fiduciaries may properly and legally invest funds, including capital in their control or belonging to them. Such bonds are hereby made securities which may properly and legally be deposited with and received by any State or municipal officer or any agency or political subdivision of the State for any purpose for which the deposit of bonds or obligations of the State is now or may hereafter be authorized by law.
N.C. Gen. Stat. § 116-196