"Downward rating pressure is likely to emerge if we revised our forecast Kiwibank's (or the consolidated group's) risk-adjusted capital ratio to below 10 per cent," Mayes said. "Although we see this unlikely given Kiwibank's business growth and capital guidance over the next two years, a significant delay or failure to inject additional capital to support its current growth objectives would place the forecast capital position under pressure--all else remaining equal."
NZ Post sold 47 per cent of its Kiwibank stake for $493.5 million in October 2016, which it used to repay $180m of debt and make a $100m dividend payment to the Crown. The New Zealand Superannuation Fund now owns 25 per cent of Kiwibank, and the Accident Compensation Corp owns 22 per cent.
Mayes said S&P would likely raise the ratings over the next two years if it believes Kiwibank has largely overcome the operational risks associated with its core banking replacement project and its risk or growth appetite does not become significantly more aggressive, particularly in light of its new shareholders.
S&P's ratings on NZ Post (A+/Stable/A-1) are unaffected by the Kiwibank downgrade, and it continues to expect NZ Post would benefit from a very high likelihood of extraordinary support from the New Zealand government in times of stress, it said.