Ga. Code § 33-11-14
An insurer may invest in the bonds, notes, certificates of indebtedness, warrants, or other evidence of indebtedness which are valid obligations issued, assumed, or guaranteed by the United States of America or any state of the United States of America, or by any county, municipal corporation, district, or political subdivision, or civil division or public instrumentality of any such government or unit of such government, if by statute or other legal requirements such obligations are payable as to both principal and interest from revenues or earnings from the whole or any part of any utility supplying water, gas, sewage disposal facility, or electricity or any other public service, including but not limited to toll roads and toll bridges, and in revenue bonds issued by any political subdivision, authority, unit, or other corporate body created by the United States government or the government of any state, for the purpose of aiding in or promoting the industrial development of such state or political subdivisions.
OCGA § 33-11-14