The trade-off between interest rate variability and the width of an exchange rate target zone is examined, using the regulated Brownian motion model of target zones. The interest rate differential’s asymptotic (unconditional) variability is increasing in the exchange rate band for narrow bands; whereas it is slowly decreasing for wide bands. The interest rate differential’s instantaneous (conditional) variability is decreasing in the exchange rate band. The model is extended to include a realignment/devaluation risk, as well as an endogenous exchange rate risk premium. The risk premium is small for reasonable parameter values.

This work selectively reviews the literature on exchange rate target zones and their theoretical and empirical methodologies and examines whether they can be used to clarify to what extent this type of exchange rate regime could contribute to greater exchange rate stability. We discuss the main contributions of the first and second generations of exchange rate target zone models. In an attempt to reconcile the poor empirical performance of the Krugman model with the reality of exchange rate target zone regimes, this line of research integrates target zones with alternative underlying economic models, such as imperfect credibility, intra-marginal interventions and sticky price models. It was thus possible to understand the correlations observed between the exchange rate, its fundamentals determinants and the interest rate differential, and to explain the fact that the statistical distribution of the exchange rate is hump shaped rather than U shaped. This implies that the initial emphasis of target zone models on nonlinearities, 'honeymoon effect', 'smooth pasting' and marginal interventions has vanished. Exchange rate target zones are better described as similar to managed floating regimes with intra-marginal interventions, with some marginal interventions when the exchange rate reaches the edges of the floating band.

This paper studies the implications of the imperfect credibility of an exchange rate target zone on the term structure of forward premia. The relationship between spot and forward exchange rates of different maturities reflects the possibility of repeated realignments of the exchange rate band. The credibility of the commitment to the target zone implicit in forward market data can be extracted by estimating the model. Application to French/German data indicates that the model is capable of matching observed patterns of interest rate differentials during the EMS, while yielding estimates of the credibility parameters that accord with the experience of the FF/DM exchange rate during the 1980s.

We present a model of a “soft” exchange rate target zone and interpret it as a stylized description of the post-August 1993 ERM. Our central bank targets a moving average of the current and past exchange rates, rather than the exchange rate’s current level, thus allowing the rate to move within wide margins in the short run, but within narrow margins in the long run. For realistic parameters, soft target zones are significantly less vulnerable to speculative attacks than “hard” target zones. These predictions are consistent with the ERM’s experience and the abatement of speculative pressure in European markets since the bands’ widening in 1993.

Drawing together new papers by some of today's leading figures in international economics and finance, Understanding Interdependence surveys the current state of knowledge on the international monetary system and, by implication, defines the research horizon for the future. Covering topics including the behavior of exchange rates, the choice of exchange-rate regime, current-account adjustment in classical and Keynesian models, the extent and effects of capital mobility, international debt, the stabilization and reform of the formerly planned economies, European monetary union, and international policy coordination, the book underscores the importance of these subjects and identifies lessons for policymakers. The contributors to the volume are Michael Bruno, Ralph C. Bryant, Richard N. Cooper, Michael P. Dooley, Barry Eichengreen, Stanley Fischer, Charles A. E. Goodhart, Peter Hooper, Peter B. Kenen, Paul R. Krugman, Henri Lorie, Jaime Marquez, Ronald I. McKinnon, Michael Mussa, Maurice Obstfeld, John Odling-Smee, Assaf Razin, Dani Rodrik, Mark P. Taylor, and John Williamson.