Skip to main content
Article thumbnail
Location of Repository

Instrumental Variable Interpretation of Cointegration with Inference Results for Fractional Cointegration.

By Francesc Mármol, Álvaro Escribano and Felipe M. Aparicio


In this paper we propose an alternative characterization of the central notion of cointegration, exploiting the relationship between the autocovariance and the cross-covariance functions of the series. This characterization leads us to propose a new estimator of the cointegrating parameter based on the instrumental variables (IV) methodology. The instrument is a delayed regressor obtained from the conditional bivariate system of nonstationary fractionally integrated processes with a weakly stationary error correction term. We prove the consistency of this estimator and derive its limiting distribution. We also show that, in the I(1) case, with a semiparametric correction simpler than the one required for the fully modified ordinary least squares (FM-OLS), our fully modified instrumental variables (FM-IV) estimator is median-unbiased, a mixture of normals, and asymptotically efficient. As a consequence, standard inference can be conducted with this new FM-IV estimator of the cointegrating parameter. We show by the use of Monte Carlo simulations that the small sample gains with the new IV estimator over OLS are remarkable.

OAI identifier:

Suggested articles


  1. (2001). E~h2,0u1k! D21~d!, (A.15) which is well defined ~cf+ Dolado and Marmol,
  2. (1991). Heteroskedasticity and autocorrelation consistent covariance matrix estimation+

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.