The Impact of Debt Levels and Debt Maturity on Inflation

In the context of a sticky price DSGE model subject to government expenditure and preference shocks where governments issue only nominal non-contingent bonds we examine the implications for optimal inflation of changes in the level and average maturity of government debt. We analyse these relationships under two different institutional settings. In one case government pursues optimal monetary and fiscal policy in a coordinated way whereas in the alternative we assume an independent monetary authority that sets interest rates according to a Taylor rule and where the fiscal authority treats bond prices as a given. We identify the main mechanisms through which inflation is affected by debt and debt maturity (a real balance effect and an implicit profit tax) and also study additional channels through which the government achieves fiscal sustainability (tax smoothing, interest rate twisting and endogenous fluctuations in bond prices). In the case of optimal coordinated monetary and fiscal policy we find that the persistence and volatility of inflation depends on the sign, size and maturity structure of government debt. High levels of government debt do lead to higher inflation and longer maturity debt leads to more persistent inflation. However even in the presence of modest price stickiness the role of inflation is minor with the majority of fiscal adjustment achieved through changes in taxes and the primary surplus. However in the case of an independent monetary authority where debt management, monetary policy and fiscal policy are not coordinated then inflation has a much more substantial and more persistent role to play. Inflation is higher, more volatile and more persistent especially in response to preference shocks and plays a major role in achieving fiscal solvency.