This article offers a theory-based explanation for why highinterest-rate countries see their currencies appreciate, the so-called UIP puzzle. The central bank bases its target rule on the lag of the policy instrument and the CPI inflation rate. When combined with a stylised model of an open economy, the endogenous target rule can account for the systematic negative relation between the change in the exchange rate and the lagged interest rate differential. Foreign inflation and the foreign interest rate also affect nominal exchange rate changes. The model-based behaviour of the exchange rate is tested on New Zealand and Australian data with mixed results.
I IntroductionAbsent any risk premium, the uncovered interest rate parity (UIP) hypothesis suggests that a positive interest rate differential (domestic interest rate minus foreign interest rate) should be compensated in full by a depreciation of the domestic currency over the term to maturity of the underlying short-term financial asset. In practice, the presumed one-for-one relationship between the interest rate differential and the expected change in the nominal exchange rate is not apparent in the data. In fact, many studies report a negative association between movements in the interest rate differential and observed changes in the nominal exchange rate. The observed violation of the UIP condition has been labelled the 'UIP Puzzle'. focus exclusively on whether uncovered interest rate parity holds between New Zealand and Australia over the 198-2008 (July) sample period. Their empirical study excludes the immediate period after the float of the Kiwi dollar as well as the peak and aftermath of the Global Financial Crisis. Following the standard atheoretical testing procedure, which relies on regressing the realised change in the nominal exchange rate on the lagged interest rate differential, they investigate whether UIP holds over the short term (90-day horizon) and over the long term (five-year and 10-year horizon, respectively). They find no evidence in favour of the UIP hypothesis over a short horizon. Over longer horizons the evidence is mixed with a 10-year horizon providing the strongest support for the theory. Burnside (2013) explores the role of New Zealand's risk premium as a factor in the country's imbalances. In this context, he also examines whether UIP holds between New Zealand and various other countries, Australia being one of them. He detects a positive yet statistically insignificant link between NZ and AUS dollar exchange rate movements and interest rate differentials over the 1990-2010 period and interprets this as evidence in favour of the UIP hypothesis.
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