We derive the probability limit of the standard Dickey-Fuller-test in the context of an exponential random walk. This result might be useful in interpreting tests for unit roots when the test is inadvertantly applied to the levels of the data when the true random walk is in the logs.

Finanzmarktdaten wie Zinsen, Aktien- oder Wechselkurse und andere spekulative Preise setzen sich durch verschiedene Besonderheiten von sonstigen ökonomischen Zeitreihendaten ab. Dieser Artikel untersucht die Konsequenzen dieser Besonderheiten für die rationale Bewertung von Finanzinstrumenten...

This paper considers a class of parametric models with nonparametric autoregressive errors. A new test is proposed and studied to deal with the parametric specification of the nonparametric autoregressive errors with either stationarity or nonstationarity. Such a test procedure can initially...