This paper analyzes the mean reversion and unit root properties of general diffusion models and their discrete samples. In particular, we find that the Dickey-Fuller unit root test applied to discrete samples from a diffusion model becomes a test of no mean reversion rather than a unit root, or more generally, nonstationarity in the underlying diffusion. The unit root test has a well defined li...

This note examines the stochastic properties of US term spreads with parametric and semiparametric fractional integration techniques. Since the observed data (rather than the estimated residuals from a cointegrating regression) are used for the analysis, standard methods can be applied. The results indicate that US Treasury maturity rates are I(1) in most cases, although the order of integratio...

I use parametric and semiparametric methods to test for the order of integration in stock market indexes. The results, which are based on the EOE (Amsterdam), DAX (Frankfurt), Hang Seng (Hong Kong), FTSE100 (London), S&P500 (New York), CAC40 (Paris), Singapore All Shares, and the Japanese Nikkei, show that in almost all of the series the unit root hypothesis cannot be rejected. The Hang Seng an...

This paper develops the approximate finite-sample bias of the ordinary least squares or quasi maximum likelihood estimator of the mean reversion parameter in continuous-time Lévy processes. For the special case of Gaussian processes, our results reduce to those of Tang and Chen (2009) (when the long-run mean is unknown) and Yu (2012) (when the long-run mean is known). Simulations show that in g...

It is well known that for continuous time models with a linear drift standard estimation methods yield biased estimators for the mean reversion parameter both in …nite discrete samples and in large in-…ll samples. In this paper, we obtain two expressions to approximate the bias of the least squares/maximum likelihood estimator of the mean reversion parameter in the Ornstein-Uhlenbeck process wi...

There has been serious suspicion of a spurious rejection of the unit roots in panel studies of PPP due to the failure to control for cross-sectional dependence. This article presents evidence of mean-reversion in industrial country real exchange rates in a set up that accounts naturally for cross-sectional dependence, is invariant to the benchmark currency and capable of detecting against regim...

Long memory or structural breaks: Can either explain nonstationary real exchange rates under the current oat? Christopher F. Baum Boston College Chestnut Hill, MA 02467 USA John T. Barkoulas Louisiana Tech University Ruston, LA 71272 USA Mustafa Caglayan Koç University Istanbul, Turkey This paper considers two potential rationales for the apparent absence of mean reversion in real exchange rate...

Abstract This paper investigates whether stock-price indices of seventeen emerging markets can be characterized as random walk (unit root) or mean reversion processes. We implement a test that can account for possible structural breaks in the underlying series and is considerably more powerful than standard tests for a random walk. We find that for fourteen countries, stock prices exhibit signi...

This paper employs non-parametric specification tests developed in Hong and Li (2005) to evaluate several one-factor reduced-form credit risk models for actual default intensities. Using estimates for actual default probabilities provided by Moody’s KMV from 1994 to 2005 for 106 U.S. firms in seven industry groups, we strongly reject popular univariate affine model specifications. As a good com...

This paper employs non-parametric specification tests developed in Hong and Li (2005) to evaluate several one-factor reduced-form credit risk models for actual default intensities. Using estimates for actual default probabilities provided by Moody’s KMV from 1994 to 2005 for 106 U.S. firms in seven industry groups, we strongly reject popular univariate affine model specifications. As a good com...