The paper contains some implications for applied econometric research. Two important ones are, first, that invertible models, such as AR or VAR models, cannot in general be used to model seasonally adjusted or detrended data. The second one is that to look at the business cycle in detrended...

In this article, we revisit the Friday the 13th effect discussed by Kolb and Rodriguez (1987) that has received increased interest in recent research. Using a dummy-augmented GARCH model, we investigate whether the occurrence of this superstitious calendar day has significant impact on the...