Optimality of public debt in an economy with incomplete markets.

Summary This doctoral dissertation analyzes optimal public debt in an economy where agents face idiosyncratic risk, credit constraints, and cannot perfectly insure themselves due to incomplete insurance markets. It extends the literature through three original contributions. The first chapter focuses on the determination of optimal debt in the presence of macroeconomic fluctuations. The second chapter introduces entrepreneurial households and analyzes their impact on the optimal debt level. The third and last chapter proposes to revisit the analysis of the optimal debt level in an economy where the government does not have a commitment technology. Through these three chapters, this thesis presents a set of ingredients and effects that contribute to a better understanding and definition of public debt policies.