OREANDA-NEWS. Fitch Ratings views positively the Reserve Bank of New Zealand's (RBNZ) consultation on the capital treatment for mortgages to residential property investors. Higher capital requirements for investor loans combined with the existing loan to value ratio (LVR) limit could help protect banks against material losses in the event of a property price correction.

The RBNZ proposes to modify existing capital rules by requiring banks to include investor mortgages in a specific asset sub-class, and hold appropriate regulatory capital for those assets. Investor mortgages in New Zealand have performed similarly to owner-occupied mortgages but the experience in other markets has shown weaker asset quality performance in a downturn. The consultation paper seeks to define the terminology of investor mortgages in order to make policy decisions by end-April 2015. Currently investor mortgages are treated the same as owner-occupier mortgages for regulatory capital purposes in New Zealand.

The introduction of higher capital rules for investor mortgages may also slow the growth rates of property prices, particularly in Auckland. Increased investor demand and a rise in investor mortgages appear to be a contributor to this strong growth, and the RBNZ's proposed limit could address some of the risks associated with these loans. The agency expects banks to charge higher interest rates on investor mortgages to offset the higher capital requirements which may deter some of the more marginal investment activity in the market. Price rises in Auckland have exceeded 10% per annum over the last 24 months which is unlikely to be sustainable in the long-term.

Investor mortgages typically have lower LVRs relative to owner-occupier loans and therefore are less susceptible to the RBNZ's existing LVR restrictions, introduced in October 2013. Banks are only allowed to underwrite a maximum of 10% of new mortgages with an LVR in excess of 80% which has reduced some potential risk in the banks' mortgage portfolios.

The new measures could also indirectly help to limit growth in household indebtedness by reducing house price appreciation closer to income growth. New Zealand's household debt, measured as a percentage of disposable income stood at 156% at end-September-2014, which is high relative to many peer countries and has increased by 5pp since 2012. Although interest rates are still low compared to the historical long-term average, a rise in the official cash rate could place borrowers at risk of being unable to service their mortgages, and may eventually lead to asset quality problems for the banks. However, this risk is partly mitigated through bank affordability testing, which includes adding a buffer above the prevailing market interest rate when assessing serviceability.