This work investigates the time series properties of the unemployment rate of the Spanish regions over the period 1976-2011. For that purpose, the authors employ the PANIC procedures of Bai and Ng (2004), which allows to decompose the observed unemployment rate series into common factor and idiosyncratic components. This enables the authors to identify the exact source behind the hysteretic behaviour found in Spanish regional unemployment. Overall, the analysis with three different proxies for the excess of labour supply renders strong support for the hysteresis hypothesis, which appears to...