Three Essays on Sovereign Default and Robust Policy Design
Doctor of Philosophy
Chapter 1 discusses the optimal fiscal response of a small open economy to business cycle fluctuations at the presence of sovereign default risks. The most recent sovereign debt crisis in Europe has demonstrated that the risk of sovereign default is not a problem in developing economies only. However, empirical studies show that fiscal policy tends to be countercyclical or acyclical in developed small open economies and procyclical in developing countries. This chapter presents a general equilibrium model with endogenous government spending, external debt financing, and sovereign default decisions for a small open economy. The model shows that developed countries’ acyclical fiscal response to productivity fluctuations can be motivated by their larger size of public sectors, lower demand elasticity of public goods, and lower volatilities of domestic investments relative to foreign investments, compared to their developing counterparts. Along this line, the recently observed fiscal policy graduation in some Latin American countries can be rationalized by the shifts in the characteristics of their public sectors towards developed countries. The model also implies that fiscal austerity is always optimal for countries with sufficiently high debt-to-output ratio, and the optimal consolidation consists of tax hikes, cuts in public consumption but not in public investment. Based on Chapman, Fang, Li and Stone (2013), Chapter 2 studies the effect of new official bailouts on capital markets when borrowing countries economic state is private information. We first analyze a game-theoretical model of crisis lending that incorporates bargaining, compliance and enforcement. The presence of asymmet- ric information yields two interesting scenarios. There are conditions under which lending reduces the risk of a deepening crisis and reduces the risk premium demanded by market actors. On the other hand, the political interests that make lenders willing to lend weaken the credibility of commitments to reform, and the act of accepting an agreement reveals unfavorable information about the state of the borrower’s economy. The net “catalytic” effect on the price of private borrowing depends on whether these effects dominate the beneficial effects of the liquidity the loan provides. Decomposing the contradictory effects of crisis lending provides an explanation for the discrepant empirical findings about market reactions, especially with regard to IMF programs. We test the implications of our theory by examining how sovereign bond yields are affected by IMF program announcements, loan size, the scope of conditions attached to loans, and measures of the geopolitical interests of the United States, a key IMF principal. Based on Li, Narajabad, and Temzelides (2013), Chapter 3 turns to the study of robust policy design when decision makers are concerned about model uncertainty. We study a dynamic stochastic general equilibrium model where agents are concerned about model uncertainty regarding climate change. An externality from greenhouse gas emissions adversely affects the economy’s capital stock. We assume that the mapping from climate change to damages is subject to uncertainty, and we adapt and use techniques from robust control theory in order to study efficiency and optimal policy. We obtain a sharp analytical solution for the implied environmental externality, and we characterize dynamic optimal taxation. A small increase in the concern about model uncertainty can cause a significant drop in optimal energy extraction. The optimal tax which restores the social optimal allocation is Pigouvian. Under more general assumptions, we develop a recursive method and solve the model computationally. We find that the introduction of uncertainty matters qualitatively and quantitatively. We study optimal output growth in the presence and in the absence of concerns about uncertainty and find that these can lead to substantially different conclusions.
Sovereign default; Fiscal policy; Crisis lending; Robust control