You are an auditor on the XYZ Limited engagement for the financial year ending 30 June 2020. XYZ is a large Australian private health insurer that also provides a range of complementary health management services and life, travel and pet insurance products. During the year, XYZ transitioned from a government business enterprise to a listed company by way of an initial public offering and listed on the ASX in November 2019. You are currently planning the XYZ audit and have noted the following information: XYZ maintains an investment portfolio (consisting of mortgage asset-backed securities, hybrid investments and direct property) to meet insurance claims. During the year, it has recorded significant investment income from its portfolio of investment assets in the face of substantial economic and market volatility (interest rates, exchange rate and equity market volatility). XYZ has experienced a spike in the number of improper (fraudulent or erroneous) health benefit claims. Management has launched a payment integrity program during the year to identify, prevent and recover improper claims. You have noticed a significant increase in the number of health insurance policies being taken out around the June/July period. Health insurance premium revenue is recognised in the income statement over the life of the policy, starting from the commencement date of the current period of insurance cover, in accordance with the pattern of the incidence of risk expected to match the seasonality of claims over the term of the insurance cover. Premium revenue relating to future financial periods is classified as an unearned premium liability. XYZ maintains a claim liability provision for the estimated cost of claims incurred but not settled at balance date. This is estimate based on the assumption that past claims settlements are an appropriate predictor of expected future claims settlement patterns. One of the XYZ main subsidiaries, NHA, has engaged in acquiring and retaining policyholders in the new-to-industry segments of the market by focusing on affordability and flexibility of its policies. Due to the nature of the industry and value of individual policies, NHA, regularly monitors its premiums in arrears and prompt recovery action is undertaken when accounts in arrears are identified. Where accounts remain in arrears past a grace period of 70 days as specified in the standard contract extended to customers, NHA's practice is to terminate these policies. NHA engages debt collection agencies to obtain settlement of accounts in arrears where all other efforts prove futile

(a) Identify the t key accounts and related assertions at risk. Briefly justify your answer

(b) Perform one substantive test of detail for each of the identified assertions at risk.