The paper develops a general stochastic macroeconomic model that can be used to study the international transmission of disturbances under four alternative exchange-rate systems: uniform flexible exchange rates, uniform fixed exchange rates, and two versions of two-tier exchange rates. The analysis makes two general points. First, one cannot assume stability of structure when assessing the consequences of alternative exchange-rate regimes. For example, the slope of the aggregate supply curve and the rationally formed expectations in the asset markets can respond dramatically to the government's choice of exchange-rate regime. Second, exchange-rate regimes that provide full insulation from foreign disturbances may nevertheless be inferior to other regimes in terms of their ability to maximize social welfare.

Evidence of excess volatilities of asset prices compared with those of market fundamentals is often attributed to speculative bubbles. This study demonstrates that bubbles could in theory lead to excess volatility, but it shows that certain variance bounds tests preclude bubbles as an explanation. The evidence ought to be attributed to model misspecification or inappropriate statistical tests. One important misspecification occurs if a researcher incorrectly specifies the time series properties of market fundamentals. A bubble‐free example economy characterized by a potential switch in government policies produces asset prices that would appear, to an unwary researcher, to contain bubbles.

Asset Price

The substantial U.S. inflations of the 1970s led to some popular support for commodity-based money. Gold has had a special role in historical commodity-money schemes, and it emerged as a leading contender in recent discussions. In October 1980 Congress established the Gold Commission to study the possible remonetization of gold. In this paper we analyze some gold monetization schemes proposed to the commission. We find that the adoption of these proposals need not lead to the price-level stability their proponents seek. Even a well-designed commodity-money scheme is a foolproof inflation guard only when the scheme's permanence is guaranteed. Permanence may possibly be guaranteed by an underlying political economy that abhors inflation, but merely the enactment of a new ephemeral rule does not ensure permanence.

Agents' beliefs in the imminent reform of a particular money supply process can have a powerful effect on their predictions of such variables as the rate of inflation. To find a criterion for monetary reform, we argue that any money supply process which does not provide a finite solution for price in a Cagan-type hyperinflationary money market will be rejected by the public. Such a process does not have the basic property of money which we call "process consistency," and we suggest that agents' subjective probabilities that their money is "process consistent" are identical to the probability that they attach to a currency reform. We compute agents' subjective probabilities that a particular money supply process is process consistent for the explosive part of the German hyperinflation, and we find that the probability of process consistency reached its lowest level in the very week in which the reform started.

When current market price depends partly on the expected rate of market price change, it is possible that the market will launch itself onto a price bubble with price being driven by arbitrary, self-fulfilling elements in expectations. The purpose of this paper is to provide some tests of the proposition that bubbles were absent during the German hyperinflation, a proposition we are unable to reject. The test methodology that we propose is general enough to be applied to other historical or contemporary episodes.

Regressions of ex post changes in floating exchange rates on appropriate interest differentials typically imply that the high-interest rate currency tends to appreciate, the "forward discount puzzle."Using data from the European Monetary System, we find that a large part of the forward discount puzzle vanishes for regimes of fixed exchange rates.That is, deviations from uncovered interest parity appear to vary in a way which is dependent upon the exchange rate regime.By using the many EMS realignments, we are also able to quantify the "peso problem.