Interest rate differentials and exchange rate behavior: a reflective analysis of foreign exchange risk management

Abstract

This paper provides a critical review on the interest rate and exchange rate connection in the field of international foreign exchange risk management. Yet—despite the prevailing interest rate/implied future exchange variance equalization philosophy (old/new theory) and especially the uncovered interest rate parity—measured unemployment aberrations complicate this relationship considerably as a new empirical proof in itself. Evidence indicates that mechanical parity adjustments account for much less of these rates than does a portfolio-consistent model, which incorporates time-varying risk premia, yield-curve dynamics, market volatility, investor behavior, and central bank policy responses. In particular, interest rate differentials are a simple proxy for both prospective return and escalating crash risk as well as the asymmetric payoff and expanding systemic tail-risk bet in a financial crisis. It also suggests that this regime dependence is the result of domestic and external factors. It also points towards priority unanswered questions in the literature surrounding causal interpretation problems, insensitivity across a range of time lags and limitations of classical risk models, which are tail-risk insensitive. The analysis then builds on these lessons to recommend abandoning the discredited practice of static hedging for more flexible state-dependent strategies that can respond to changes in volatility, policy, and structural currency mispricing by multinationals and other financial institutions. At the end of the day, FX risk management is much more than mathematical models: it is a matter of understanding uncertainty, sentiment, and human choice that drives financial realities.