Exchange rates dependence

"Exchange rate movements are difficult to predict but there appear to be discernible patterns in how currencies jointly appreciate or depreciate against the dollar. In this paper, we study the dependence structure of a number of exchange rate pairs against the dollar. We employ a conditional copula approach to recover the joint distributions for pairs of exchange rates and study both the correlation and the upper and lower tail dependence of these distributions. We analyze changes in dependence measures over time, and we investigate whether these measures are affected by the business cycle or interest rate differentials. Our results show that dependencies are indeed time-varying. We find that foreign and U.S. recessions affect the joint dependence structure and that currencies with higher interest rate differentials tend to move less closely together, not only on average (correlation), but also when extreme events occur (tails)"--Federal Reserve Board web site.