Tenn. Code § 7-53-309
Bonds issued under the authority of this chapter and secured by a pledge of full faith and credit shall be and are hereby declared to be legal and authorized investments for banks, savings banks, trust companies, savings and loan associations, insurance companies, fiduciaries, trustees, guardians and for all public funds of the state, including, but not limited to, the sinking funds of cities, towns, villages, counties, school districts, or other political corporations, or subdivisions of the state. Such bonds shall be eligible to secure the deposit of any and all public funds of the state, and any and all public funds of cities, towns, villages, counties, school districts or other political corporations or subdivisions of the state, and such bonds shall be lawful and sufficient security for the deposits to the extent of their value when accompanied by all unmatured coupons appertaining to the bonds.
T.C.A. § 7-53-309