Market Fundamentals versus Speculative Bubbles: A New Test Applied to the German Hyperinflation.

We develop and apply a method of testing for speculative bubbles. The method is designed to overcome two well-known problems in the identification of bubble phenomena--the problem of distinguishing any type of bubble from an expected future change in market fundamentals and the problem of detecting a periodically-collapsing bubble when the residuals of the fundamentals regression are integrated. We propose the strategy of estimating a switching regime model of market prices, partialling out expected changes in fundamentals and carefully analysing the properties of the residuals. Extending our analysis, we also propose a more direct test for bubbles, based on the estimation of the general (fundamentals-plus-bubble) solution for market prices. We apply our methodology to the study of German hyperinflation in the 1920s. We find evidence consistent with the existence of a bubble during that hyperinflation. Copyright @ 1996 by John Wiley & Sons, Ltd. All rights reserved.