Economic time series exhibit periodically recurrent movements at the daily, weekly, and monthly levels. Also known as seasonality, it has been usually treated as a nuisance to be removed prior to analysis. Often, data is already deseasonalised by data providers since it distracts from medium-term time trends and long-term cycles. Moreover, seasonality disappears when data are aggregated to a yearly basis – it is a phenomenon at work at shorter time frames. It is an…