We develop a macroeconomic model where the government does not guarantee to repay debt. We ask whether movements in the price of government bonds can be rationalized by lenders' unwillingness to fully roll over debt when the outstanding level of debt exceeds the government's repayment capacity....

In this paper we characterize quantitatively the optimal mix of progressive income taxes and education subsidies in a model with endogenous human capital formation, borrowing constraints, income risk and incomplete financial markets. Progressive labor income taxes provide social insurance...

We ask whether a PAYG-financed social security system is welfare improving in an economy with idiosyncratic and aggregate risk. We argue that interactions between the two risks are important for this question. One is a direct interaction in the form of a countercyclical variance of idiosyncratic...