An insurer may invest in:

(1) Bonds, notes, or other evidences of indebtedness which are secured by a first mortgage lien or deed of trust upon unencumbered improved real property located in the United States or Canada, including leasehold estates in such real estate having an unexpired term (inclusive of the term or terms which may be provided by options of renewal) of not less than 10 years beyond the final maturity of the loan. Unless guaranteed or insured by the Administrator of Veterans Affairs, the Secretary of Housing and Urban Development, or by a mortgage guaranty insurance policy issued by an insurance company licensed and authorized to do business by and in the State of Alabama, no such mortgage loan or loans when made shall exceed 75 percent of the fair value of the real estate or leasehold, except that loans made on single family dwellings shall not exceed 80 percent of the fair value of the property. "Fair value" shall be determined by a competent appraiser or appraisers. For the purposes of this section and Section 27-41-30, real estate shall not be deemed to be encumbered by reason of the existence of taxes or assessments that are not delinquent, instruments creating or reserving mineral, oil, or timber rights, rights-of-way, joint driveways, sewer rights, public utility easements, rights in walls, nor by reason of building restrictions or other restrictive covenants, nor when such real estate is subject to lease in whole or in part whereby rents or profits are reserved to the owner; provided, that the security created by the mortgage or trust deed on the real estate is a first lien upon such real estate and that there is no condition or right of re-entry or forfeiture under which such lien can be cut off, subordinated, or otherwise disturbed.

(2) Bonds, notes, or other evidences of indebtedness which are secured by mortgage or deed of trust on real estate or an interest in real estate in the United States, if payment of such indebtedness or part thereof is guaranteed or insured by the Administrator of Veterans Affairs in accordance with the Servicemen's Readjustment Act of 1944, as amended. Any portion of a mortgage loan referred to in this subdivision which is not guaranteed as herein provided must not exceed 75 percent of the fair value of the property as defined in subdivision (1) above.

(3) Bonds, notes, or other evidences of indebtedness which are secured by mortgage or deed of trust insured by the Secretary of Housing and Urban Development under the terms of the National Housing Act, as amended.

(4) Purchase money mortgages shall be valued as provided in Section 27-37-9.

(5) Bonds, notes, or other evidences of indebtedness which are secured by a first mortgage lien or deed of trust upon unencumbered improved or income-bearing real property located in the United States or Canada, including leasehold estates in such real estate having an unexpired term of not less than 10 years beyond the final maturity of the loan where the borrower is a solvent corporation engaged in any lawful business and existing under the laws of the United States or any real estate of the United States or Canada, or any province thereof, if such corporation has not defaulted in the payment of principal and interest on any of its fixed interest obligations during five years preceding the date of investment and the amount of indebtedness does not exceed 100 percent of the value of the property.