Maximum likelihood estimation of the multivariate fractional cointegrating model

Departures from an economic equilibrium should be mean reverting. The deviations are often assumed to be integrated of order zero but this is too restrictive. It is sufficient that the shocks are integrated of an order less than one, i.e. they may be fractionally integrated. A fractionally cointegrated system is developed. Further, estimation and testing are discussed, analytically and by Monte Carlo simulations. The Monte Carlo simulations shows that it is much more severe to ignore fractional cointegration than incorporating it when it is not present.