(a) An insurer may invest in equipment trust obligations or certificates which are adequately secured evidencing an interest in transportation equipment wholly or in part within the United States and a right to receive determined portions of rental, purchase, or other fixed obligatory payments for the use or purchase of such transportation equipment.

(b) An insurer may invest in notes, bonds, debentures, or other evidences of indebtedness secured by an interest in manufacturing, mining, or generating machinery and equipment located wholly within the United States evidencing a right to receive determined portions of rental, purchase, or other fixed obligatory payments for the use or purchase of such machinery and equipment.

(c) An insurer may invest in notes, bonds, debentures, or evidences of indebtedness secured by a lease of manufacturing, mining, computer equipment, or generating machinery and equipment or a lease of other tangible personal property or by a contract or by an agreement requiring aggregate payments sufficient to pay all fixed charges, including maintenance, upkeep and repair, insurance charges and taxes, and to pay the installments of principal and interest and any other payments required by the instrument evidencing the indebtedness.

(d) The lessee or party contracting or agreeing to make such payments under subsections (a), (b), or (c) of this section must be the United States or an agency thereof, a state of the United States, or a civil division or governmental unit thereof or a solvent institution whose fixed interest obligations, if any, would be eligible investments under Section 27-41-15.