This paper examines both the linear and nonlinear causal relationships between crude oil price changes and stock market returns for the United States. In particular, the study applied a battery of unit root tests to ascertain the time series properties of crude oil price changes and stock market...

This paper presents a test for exogeneity of explanatory variables in a nonparametric instrumental variables (IV) model whose structural function is identified through a conditional quantile restriction. Quantile regression models are increasingly important in applied econometrics. As with...