The refund payments to around 216,000 customers include an additional amount of interest to recognise the time elapsed since the relevant benefit was not applied. CBA reported this matter to the Australian Securities and Investments Commission under its breach reporting obligations in the Corporations Act, ASIC said in a statement.

For an annual fee, the Wealth Package (for some customers described as “Mortgage Advantage Package”) offered benefits such as interest rate discounts and fee waivers in relation to a range of products including home loans, credit cards, transaction accounts, personal loans, overdrafts and insurance.

CBA relied on staff to manually apply many of the discounts available under the Wealth Package. Investigations revealed that an exception report, which was designed to detect when the discounts were not properly applied, was not working properly, ASIC continued.

CBA discovered the breach following a customer complaint and reported it to ASIC in 2014, the regulator said.

The bank “committed to fully investigate the cause of the breach and the impact on all eligible Wealth Package holders,” ASIC said, adding that the bank also hired Ernst & Young to review and provide recommendations to improve controls, ensure its remediation process would identify all those affected, and ensure an accurate calculation of refunds.