This thesis develops theoretical macroeconomic models that contribute to the policy debate by providing new insights on fiscal-monetary interactions. It is composed of three chapters that emphasise the role of government debt (maturity) in shaping private sector's expectations and in stabilising the macroeconomy. The first chapter studies the importance of coordination between timeconsistent fiscal and monetary policy for macroeconomic outcomes during a liquidity trap episode. It shows how central bank independence may imply a negative effect of government debt on consumption when the zero lower bound on interest rates is binding. In this context, long-lasting consolidation of debt turns out optimal to keep inflation below target at positive interest rates and lower interest rate expectations. The second chapter (co-authored with Boris Chafwehé and Rigas Oikonomou) explores the effectiveness of government debt maturity management as an additional margin to stabilise inflation in a world of fiscally dominated monetary policy. A properly tailored maturity portfolio turns out to restore the efficacy of monetary policy under certain conditions about its (optimal) conduct. The third chapter offers a new insight on deficit-financed fiscal policy in a lowrate environment by considering liquidity traps that are caused by long-lasting shifts in expectations. Fiscal stimuli should include additional measures to contain debt accumulation in this case.

Recently, monetary authorities have increasingly focused on implementing policies to ensure price stability and strengthen central bank independence. Simultaneously, in the fiscal area, market development has allowed public debt managers to focus more on cost minimization. This “divorce” of monetary and debt management functions in no way lessens the need for effective coordination of monetary and fiscal policy if overall economic performance is to be optimized and maintained in the long term. This paper analyzes these issues based on a review of the relevant literature and of country experiences from an institutional and operational perspective.

This essay empirically investigates the dynamics between government debt and budget deficits in the United States during a recession as opposed to an expansion. We use four different budget deficits definitions to develop a more comprehensive insight. We estimate a threshold VAR model on quarterly data from 1947: Q1 to 2016: Q3 on debt to GDP and budget deficits to GDP ratio for the United States. Specification test using LR test rejects the null for a linear VAR against nonlinear VAR. The nonlinear impulse responses indicate, with an increase to budget deficits to GDP ratio, government debt to GDP ratio rise faster during a recession as opposed to an expansion, and tend to move in a counter-cyclical manner with an increase in the output gap. We can thus infer that governments chose economic stability over fiscal balance during recessions. With an increase in government debt to GDP ratio, nonlinear impulse response show budget deficits to GDP ratio grow faster during an expansion as opposed to a recession and exhibit counter-cyclicality with an increase in the output gap. All four budget defi cits definitions depict similar pattern. Robustness check, using cyclically adjusted primary budget deficit published by the congressional Budget Office, also con rm the above findings. In this essay, we explore the presence of a long run relationship between the monetary base and the government debt using monthly data from 1942:1 to 2015:12. We apply formal statistical methods including cointegration and threshold cointegration tests to investigate the presence of a long-run relationship and estimate a threshold vector error-correction model (TVECM henceforth) to analyze the short-run dynamics. We find the presence of a threshold cointegration between the monetary base and government debt. As for the short-run dynamics, TVECM estimates show that the speed of adjustment is significant for the growth in debt equation in both regimes with the signs indicating government adjusting the debt in the short-run. But the U.S. Fed does not change the monetary base, hence we do not find any evidence of debt monetization in the U.S. We evaluate our findings over two sub-samples: 1946 to 2015 and 1946 to 2007 for robustness purposes. Findings from both sub-samples conform to our findings from the full sample. In this essay, we investigate the impacts of growth in the budget deficit and money supply on real interest rate are integral to contemporary macroeconomic policy. We employ threshold VAR and nonlinear impulse responses using quarterly data from 1959 to 2015. We find that growth in money supply and budget deficits have an asymmetric impact on inflation, short-term interest rate, and real interest rates. Growth in money supply and budget deficit tend to make the real interest rate negative in a bad state. In a good state, on the other hand, growth in money supply tend to increase the real interest rate but growth in budget deficits tend to decrease the real interest rate over the forecast horizon.

The initial government debt-to-GDP ratio and the government’s commitment play a pivotal role in determining the welfare-optimal speed of fiscal consolidation in the management of a debt crisis. Under commitment, for low or moderate initial government debt-to-GPD ratios, the optimal consolidation is very slow. A faster pace is optimal when the economy starts from a high level of public debt implying high sovereign risk premia, unless these are suppressed via a bailout by official creditors. Under discretion, the cost of not being able to commit is reflected into a quick consolidation of government debt. Simple monetary-fiscal rules with passive fiscal policy, designed for an environment with “normal shocks”, perform reasonably well in mimicking the Ramsey-optimal response to one-off government debt shocks. When the government can issue also long-term bonds–under commitment–the optimal debt consolidation pace is slower than in the case of short-term bonds only, and entails an increase in the ratio between long and short-term bonds.

The global economy has experienced four waves of rapid debt accumulation over the past 50 years. The first three debt waves ended with financial crises in many emerging market and developing economies. During the current wave, which started in 2010, the increase in debt in these economies has already been larger, faster, and broader-based than in the previous three waves. Current low interest rates mitigate some of the risks associated with high debt. However, emerging market and developing economies are also confronted by weak growth prospects, mounting vulnerabilities, and elevated global risks. A menu of policy options is available to reduce the likelihood that the current debt wave will end in crisis and, if crises do take place, will alleviate their impact.

The essays in this volume reflect on the fact that in all countries debt and deficits of the public sector are at heart: of economic policy debate. Debt and deficits pose major problems, all the more pressing in Europe because of the Maastricht criteria for entry into European Monetary Union. In the developing world debt has been associated with major financial crises.

This paper reviews the theoretical and empirical literature on the effectiveness of fiscal policy. The focus is on the size of fiscal multipliers, and on the possibility that multipliers can turn negative (i.e., that fiscal contractions can be expansionary). The paper concludes that fiscal multipliers are overwhelmingly positive but small. However, there is some evidence of negative fiscal multipliers.