(a) An insurer or health maintenance organization may assume a subordinated liability for repayment of a loan or advance described by Section 427.051 and payment of interest on the loan or advance if the insurer or health maintenance organization and the creditor execute a written agreement stating that the creditor may be paid only out of that portion of the insurer’s or health maintenance organization’s surplus that exceeds the greater of:
(1) a minimum surplus amount set in the agreement; or
(2) a minimum surplus amount of $500,000.
(b) The department or commissioner may not require the agreement to provide a minimum surplus amount that is different from the amount described by this section.