Iowa Code § 432.9: Debts deductible.

In ascertaining the indebtedness or liability of such corporation, company, or association, a debt shall be deemed to exist on account of its liability on the policies, certificates or other contracts of insurance issued by it equal to the amount of the surplus or other funds accumulated by any such corporation or association for the purpose of fulfilling its policies, certificates, or other contracts of insurance, and which can be used for no other purpose.