These are: whether the exchange rate is exceptional relative to history; is the exchange rate justified; would intervention be consistent with the PTA; and whether the market conditions exist to successfully shift the value of the currency.
Even if the first three criteria are satisfied at a point in time, it makes little sense to risk incurring losses to taxpayers by intervening when currency flows supporting the New Zealand dollar are particularly strong. But we will remain vigilant on these criteria and will be prepared to intervene if all conditions are met.