Rational Speculative Bubbles In An Exchange Rate Target Zone

The papers in this book are grouped into three sections: the first on price bubbles is primarily financial; the second on speculative attacks (on exchange rate regimes) is international in scope; and the third, on policy switching, is concerned with monetary policy.

Over the past few decades, a clear trend has emerged worldwide toward the devolution of spending and, to a lesser extent, revenue-raising responsibilities to state and local levels of government. One view is that the decentralization of spending responsibilities can entail substantial gains in terms of distributed equity and macroeconomic management. The papers in this volume, edited by Teresa Ter-Minassian, examine the validity of these views in light of theoretical considerations, as well as the experience of a number of countries.

The recent theory of exchange rate dynamics within a target zone holds that exchange rates under a currency bard are less responsive to fundamental shocks than exchange rates under a free float, provided that the intervention rules of the Central Bank(s) are common knowledge. These results are derived after having assumed a priori that excess volatility due to rational bubbles does not occur in the foreign exchange market. In this paper we consider instead a setup in which the existence of speculative behavior is a datum the Central Bank has to deal with. We show that the defense of the target zone in the presence of bubbles is viable if the Central Bank accommodates speculative attacks when the latter are consistent with the survival of the target zone itself and expectations are self-fulfilling. These results hold for a large class of exogenous and fundamental-dependent bubble processes. We show that the instantaneous volatility of exchange rates within a bard is not necessarily less than the volatility under free float and analyze the implications for interest rate differential dynamics.

In this paper we generalize the target zone exchange rate as model formalized by Krugman (1988b). The main contributions of these pages consist of linking the recent developments in the theory of target zones to the mirror image theory of speculative attacks on asset price fixing regimes and in using aspects of that linkage to give an intuitive interpretation to the “smooth pasting” condition often invoked as a terminal condition. We aim to unify these two literatures by showing that the solution concepts in both are identical.

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.

This reference accords recognition to the recent revolution in macroeconomics wrought by imperfect competition. Grossman and Rogoff (Princeton U.) present chapters by two dozen contributors on two prime areas of research interest: international trade theory and policy (e.g. strategic trade patterns and policies, the relationship between trade and technological progress), and open economy macroeconomics and international finance (covering such topics as exchange rates, foreign lending, and policy coordination). The volume commences with Krugman's overview of the positive theory of international trade, and concludes with analyses of sovereign debt. Annotation copyrighted by Book News, Inc., Portland, OR.

This edited volume examines capital mobility in both industrialised and developing countries.

3 On the Economic Relevance of Rational Bubbles 79 3. 1 Capital markets . . . . . . . . . 80 3. 1. 1 Efficient capital markets 86 3. 1. 2 Rational bubbles on capital markets. 93 3. 1. 3 Economic caveats . 103 3. 2 Foreign exchange markets 109 3. 3 Hyperinflation. . . . . . . 117 4 On Testing for Rational Bubbles 123 4. 1 Indirect tests . . . . . . . . . 123 4. 1. 1 Variance bounds tests 124 4. 1. 2 Specification tests . . . 137 4. 1. 3 Integration and cointegration tests 140 4. 1. 4 Final assessment of indirect tests . 150 4. 1. 5 A digression: Charemza, Deadman (1995) analysis. 151 4. 2 Direct tests . . . . . . . . . . . . . . . . . . . . . . . . 157 4. 2. 1 Deterministic bubble in German hyperinflation. 158 4. 2. 2 Intrinsic bubbles on stock markets. 163 4. 2. 3 An econometric caveat . . . . . 168 4. 2. 4 Final assessment of direct tests 172 5 On the Explanatory Power of Rational Bubbles on the G- man Stock Market 175 5. 1 Data . . . . . . . 175 5. 2 Direct test for rational bubbles 181 5. 2. 1 Temporary Markovian bubbles. 184 5. 2. 2 Temporary intrinsic bubbles . . 193 ix 5. 2. 3 Permanent intrinsic bubbles 198 5. 3 A digression: Testing for unit roots 204 6 Concluding Remarks 215 A Results 221 A. 1 Temporary markovian bubbles. 221 A. 2 Temporary intrinsic bubbles . . 225 A. 3 Permanent intrinsic bubbles - Class 1 to 2 229 A. 4 Permanent intrinsic bubbles - Class 3 to 6 230 A. 5 Integration tests. . . . . . . . . . . . . . .