Any insurer may secure its required funds for reserve purposes by means of contributions or loans, but subject to the limitations set forth in this section. Any fund so secured is hereinafter described as a guaranty fund. The agreement upon which a guaranty fund is secured shall provide that any claim for its return is inferior and subordinate to all claims of and reserves for policyholders and insured members and to the statutory required contingency reserve deposit and is subject to the approval of the commissioner. The guaranty fund and agreed interest on the guaranty fund accrued in a manner and at a rate approved by the commissioner shall not be liabilities or claims against the insurer or any of its assets except as provided in this section. Interest shall be paid and principal shall be retired only out of surplus of the insurer in excess of current obligations and of reserves required by this chapter. No part of principal shall be retired or interest paid unless the surplus remaining after repayment is determined adequate to comply with section 403 and the insurer has received the written consent of the commissioner. No commission or promotion expense of any kind shall be paid or allowed in connection with the raising of the guaranty fund, and the amount of the guaranty fund together with interest on the fund and any portion of the fund retired during any year shall be reported in the insurer’s annual statement. This section does not bar any insurer subject to this section from borrowing money, but the amount borrowed with accrued interest shall be carried by the insurer as an immediate liability, as distinguished from the deferred or contingent liability status of the guaranty fund.