Public debt has continued to grow in 2017 until breaking historical records in most Western economies. This problem will force governments to consider the need to review the revenue and public expenditure models, especially if we take into account the added problem of the sustainability of the pension model in countries whose population pyramids are inverse. Based on these premises, and considering the influence of financial markets and central banks, how should public finances evolve to achieve sustainability? Increase in tax burden, reduction of social expenditures or search for efficiency?