(a) Bonds issued under this subchapter are legal and authorized investments for banks, savings banks, trust companies, building and loan associations, savings and loan associations, insurance companies, fiduciaries, trustees, and guardians, and for the sinking funds of cities, towns, villages, counties, school districts, and other political corporations and subdivisions of the state.
(b) The bonds are eligible to secure the deposit of the public funds of the state, cities, towns, villages, counties, school districts, and other political corporations and subdivisions of the state.

(c) The bonds are lawful and sufficient security for deposits to the extent of their value when accompanied by all unmatured coupons.