(a) District bonds are legal and authorized investments for:
(1) banks;
(2) trust companies;
(3) savings and loan associations;
(4) insurance companies;
(5) fiduciaries;
(6) trustees;
(7) guardians; and
(8) sinking funds of municipalities, counties, school districts, and other political subdivisions of the state and other public funds of the state and its agencies, including the permanent school fund.
(b) District bonds are eligible to secure deposits of public funds of the state and municipalities, counties, school districts, and other political subdivisions of the state. The bonds are lawful and sufficient security for deposits to the extent of their value when accompanied by all unmatured coupons.