Mildly explosive autoregressions have been extensively employed in recent theoretical and applied econometric work to model the phenomenon of asset market bubbles. An important issue in this context concerns the construction of confidence intervals for the autoregressive parameter that...

The literature on heteroskedasticity and autocorrelation robust (HAR) inference is extensive but its usefulness relies on stationarity of the relevant process, say Vt, usually a function of the data and estimated model residuals. Yet, a large body of work shows widespread evidence of various...

We provide nonparametric quantile regressions to test for autocorrelation patterns for weekly and monthly stock returns. We test in four developed markets (North America, Europe, Japan, and Asia without Japan) and five market-size portfolios. We find greater heteroskedasticity for the...