The Reserve Bank of Australia "concurs with the Interim Report's caution regarding unproven macroprudential tools," it said in its second submission to the Murray inquiry."The bank and the other agencies view macroprudential policy as being subsumed within the broader financial stability policy framework in Australia," it said in the submission.APRA "has adapted its prudential intensity in light of developments in systemic risk," the RBA said, speaking, as is so often the case, for an introverted prudential regulator."For example, following signs of increased risk appetite in the mortgage market, APRA recently surveyed mortgage underwriting standards, released guidance on managing mortgage risk, and asked the major banks to specify how they are monitoring lending standards and the ensuing risks to the economy."Tools like loan-to-valuation ratio and debt-servicing ratio limits on mortgages "have only recently begun to be used in developed countries," the RBA said, leaning toward delay."It is still too early to judge their effectiveness with the available evidence so far mixed. The effects of particular initiatives are not easily disentangled from those of other policy settings, including changes in monetary policy. "APRA "already has the powers to implement these tools" if it was decided they were needed, the RBA said.