(a) Bonds issued under this subchapter are legal and authorized investments for:
(1) banks, trust companies, and savings and loan associations;
(2) all insurance companies;
(3) fiduciaries, trustees, and guardians; and
(4) interest funds, sinking funds, and other public funds of the state or of an agency, subdivision, or instrumentality of the state, including a county, municipality, school district, or other district, public agency, or body politic.
(b) Bonds issued under this subchapter may be security for deposits of public funds of the state or of an agency, subdivision, or instrumentality of the state, including a county, municipality, school district, or other district, public agency, or body politic, to the extent of the market value of the bonds, if accompanied by any appurtenant unmatured interest coupons.