Abstract
There is a paucity of methodologically sound studies directly addressing exchange rate
and inflation volatilities, and the existing ones suggest a relation between these variables,
although there is no consensus about its characteristics. Therefore, it is necessary to verify
the effects of exchange rate volatility, especially under an inflation-targeting regime where the
monetary authority must know, as precisely as possible, the factors that affect price behavior.
This paper seeks to establish the relation between exchange rate and inflation volatilities by
adopting a more sophisticated econometric methodology than those applied so far - a
bivariate GARCH model, dealing directly with the effects of conditional volatilities, which has
been largely unexplored by the literature. We find a semi-concave relation between exchange
rate and inflation variances, differently from what was estimated for financial series and in line
with the intuition obtained from other studies. The article innovates by (i) trying to establish a
relation between exchange rate and inflation volatilities and its implication for the monetary
policy, (ii) applying a multivariate GARCH model, using conditional variances to analyze the
relation between those volatilities and (iii) showing that traditional tests performed with
exogenously constructed volatility series are sensitive to the criteria chosen to construct such
series and do not reveal relevant features of that relation.