This study provides a critical assessment of long-horizon return predictability tests using highly persistent regressors. We show that the most commonly used test statistics are typically oversized, leading to spurious inference. As a remedy, we propose a simple Wald statistic, which can...

This study examines stock return predictability via lagged financial variables with unknown stochastic properties. We conduct a battery of predictability tests for US stock returns during the 1927-2012 period, proposing a novel testing procedure which: i) robustifies inference to the degree of...