The Reserve Bank of New Zealand has revoked ANZ Bank New Zealand's accreditation to model its own operational risk capital requirement due to a "persistent failure" in its controls and attestation process.

ANZ is one of four big banks in New Zealand that are accredited by the Reserve Bank to use their own risk models – the internal models approach - in calculating their regulatory capital requirements.

"Accreditation is earned through maintaining high risk-management standards, and comes with stringent responsibilities for the bank's directors and management," said Deputy Governor Geoff Bascand.

ANZ is now required to use the standardised approach for calculating appropriate operational risk capital. From March 2019, this will increase its minimum capital held for operational risk by around 60 per cent, to $760 million, the RBNZ said.


ANZ New Zealand said it "accepts the RBNZ's decision that the ORC model to be used from now will be based on the RBNZ's standardised approach." ANZ says it discovered it wasn't using an approved model during an internal review.

As a result, as at 31 March 2019, ANZ New Zealand's ORC requirement increased by $277m, and its capital ratios have decreased by 0.4 per cent for common equity tier 1 capital and 0.6 per cent for total capital, it said.

All four of the banks allowed to use their own models for calculating risk are Australian owned and they account for about 88 per cent of New Zealand's banking system.

The decision comes as the Reserve Bank is currently consulting on its capital framework for banks.

Among the many decisions to be made, and in part due to proven weaknesses with the internal models approach, it is proposing that all banks adopt a new standardised approach for calculating operational risk capital, it said. The bank capital proposals were announced on December 14 last year and after a couple of extensions, the consultation period is set to end today.

According to Bascand, the RBNZ had encouraged ANZ to review its attestation and assess its compliance with capital regulations.

"It's failure to use an approved model was revealed through that review," he said.

"ANZ's directors have attested to compliance, despite the approved model not being used since 2014. The fact that this issue was not identified for so long highlights a persistent weakness with ANZ's assurance process," he added.


"We continue to work with ANZ in assessing its systems controls before determining any further action." ANZ said that its board and management takes the attestation regime "very seriously" and while it "believes it has appropriate controls and attestation processes in place, it will work with the RBNZ in its assessment of those controls and processes."

A bank's disclosure statement is required to contain certain statements signed by each director of the bank. These must state, among other things: whether the bank has systems in place to monitor and control adequately the banking group's material risks and whether those systems are being properly applied; and whether the bank has complied with its conditions of registration over the period covered by the disclosure statement.

"These directors' attestations are important because they strengthen the incentives for directors to oversee, and take ultimate responsibility for, the sound management of their bank," Bascand said.