(a) Certificates approved by the attorney general are legal and authorized investments for:
(1) banks, savings banks, trust companies, and savings and loan associations;
(2) insurance companies;
(3) fiduciaries, trustees, and guardians; and
(4) sinking funds of municipalities, counties, school districts, or other political corporations or subdivisions of the state.
(b) Certificates approved by the attorney general are eligible to secure deposits of public funds of the state or a municipality, county, school district, or other political corporation or subdivision of the state. The certificates are sufficient security for the deposits to the extent of the face value of the certificates, if accompanied by any appurtenant unmatured interest coupons.