The Reserve Bank – Te Pūtea Matua and the Minister of Finance have agreed to update their shared Memorandum of
Understanding (MoU) on macro-prudential policy and add debt serviceability restrictions to the list of potential tools
In February, the Minister of Finance issued a formal direction to the Reserve Bank (under section 68B of the Reserve
Bank Act) for us to have regard to house price sustainability when making financial stability decisions. This is
separate from the Monetary Policy Committee’s monetary policy remit.
The Minister also requested more information and analysis on debt-to-income ratios and interest-only mortgages. The Bank
provided this advice to the Minister last month, and we are today releasing it publically.
Our analysis detailed that debt serviceability restrictions, such as a Debt-to-Income (DTI) limit, are likely to be the
most effective additional tool that could be deployed by the Reserve Bank to support financial stability and house price
sustainability. The analysis also demonstrated that any such restrictions would impact investors most powerfully while
having limited impact on first home buyers. In our advice we also noted that we consider that a DTI limit would be a
complementary tool to mortgage Loan-to-Value Ratio (LVR) restrictions as they address different dimensions of
housing-related risk; DTIs reduce the likelihood of mortgage defaults while LVRs largely reduce losses to banks if
In his response, the Minister has agreed to add debt serviceability restrictions to the MoU in principle, on the
condition that any implementation is designed to avoid impact, as much as possible, to first home buyers. We will now
work with the Treasury to update the wording for the MoU, which will need to be approved by the Minister.
“Although we do not have a remit to target house prices directly, our financial policy tools can help to ensure prices
do not deviate too far from sustainable levels,” Reserve Bank Governor Adrian Orr says.
“We believe that a ‘sustainable house price’ is the level that the price would be expected to move towards over several
years, reflecting the underlying drivers of supply and demand for housing, including population growth, building costs,
land supply, and interest rates.”