This paper considers the estimation of a semi-parametric single-index regression model that allows for nonlinear predictive relationships. This model is useful for predicting financial asset returns, whose observed behavior is described by a stationary process, when the multiple non-stationary...

We consider the problem of hypothesis testing in a modified version of the stochastic integration and cointegration framework of Harris, McCabe and Leybourne (2002). This nonlinear setup allows for volatility in excess of that catered for by the standard integration/cointegration paradigm...