The problem which treats internal assurance is that of not insurable risks, in this particular case operational risk: “the risk of loss resulting from the inadequacy or from the failing of any internal process or outside events”.
riskosoft.wordpress.com/2007/04/17/risk-insurance-management-the-assurance-of-risks-not-assurable-riskosoft-enterprise-risk-metrics-erm-solution-of-risk-management-accounting/
