The IMF Working Papers series is designed to make IMF staff research available to a wide audience. Almost 300 Working Papers are released each year, covering a wide range of theoretical and analytical topics, including balance of payments, monetary and fiscal issues, global liquidity, and national and international economic developments.
In the paper we show that, most of the time, smooth reduction in the debt ratio is optimal for tax-smoothing purposes when fiscal risks are asymmetric, with large debt-augmenting shocks more likely than commensurate debt reducing shocks. Asymmetric risks are a feature of 200 years of data for the U.S. and the U.K.: rare but recurrent large surges of the debt-to-GDP ratio, followed by very gradual but persistent declines over long periods. More informal evidence from many other countries suggests that asymmetry is a general feature of fiscal shocks. The gradual smooth reduction in the public debt to GDP ratio is not a response to past developments. Instead it is optimal given recurrent fiscal risks and the empirical characteristics of fiscal shocks. The behavior of the debt-to-GDP ratio in the U.K. and the U.S. seems roughly compatible with the prescriptions of the tax-smoothing model.