Bonds issued under this chapter are legal and authorized investments for:
(1) banks;
(2) savings banks;
(3) trust companies;
(4) building and loan associations;
(5) insurance companies;
(6) fiduciaries;
(7) trustees;
(8) guardians; and
(9) sinking funds of cities, towns, villages, counties, school districts, and other political subdivisions and public agencies of the state.