(a) Authority bonds are legal and authorized investments for a bank, savings bank, trust company, savings and loan association, insurance company, fiduciary, trustee, or guardian, or a sinking fund of a municipality, county, school district, or political subdivision of the state.
(b) Authority bonds may secure deposits of public funds of the state, a municipality, a county, a school district, or another political corporation or subdivision of the state. The bonds may provide this security in an amount up to their value, if all unmatured coupons, if any, are attached.