We study hypotheses testing in the presence of a possibly singular covariance matrix. We propose an alternative way to handle possible non-regularity in a covariance matrix of a Wald test, using the identity matrix as the weighting matrix when calculating the quadratic form. The resulting test...

In this paper we consider several modified wild bootstrap methods that, additionally to heteroskedasticity, can take dependence into account. The modified wild bootstrap methods are shown to correctly replicate an invariance principle for multivariate time series that are characterized by...

Most panel data studies of the predictability of returns presume that the cross-sectional units are independent, an assumption that is not realistic. As a response to this, the current paper develops block bootstrap-based panel predictability tests that are valid under very general conditions....