This shortage of safe assets facing a huge demand is one of the important causes behind the very low levels of government bonds yields. As Caballero and Farhi (2017) stated “Short‐term rates feature a widely noted downward secular trend and a sharp drop during the Great Recession.
The models, estimated on data plainly belonging to a different population than that involved in the forecast, cease providing a reliable representation of the way the economy works, often without even producing indications serving to identify the adjustments that could lessen the deficiencies.