Varying-coefficient linear models arise from multivariate nonparametric regression, nonlinear time series modelling and forecasting, functional data analysis, longitudinal data analysis, and others. It has been a common practice to assume that the vary-coefficients are functions of a given...

In studies of time series momentum (TSM), the Newey-West t-test has size distortion for linear predictive regression with excess returns because of non-stationarity, endogeneity due to correlated errors, and a lack of finite moments due to heavy tails. To solve these problems, we propose a new...