This paper uncovers a mechanism by which bubbles crowd in capital investment. If capital formation is initially depressed by a binding credit constraint, a bubble triggers a savings glut. Higher returns in a new bubbly equilibrium attract additional savings, which are channeled to expand investment at the extensive margin, leading to permanently higher capital, output, and wages. We demonstrate that crowding-in through this channel is a robust phenomenon that occurs along the entire time path.

We consider a linear growth model with idiosyncratic productivity shocks in which producers cannot commit to repay their loans. Borrowing constraints are determined endogenously by the borrowers' incentives to repay, assuming that defaulters lose a share of output and are excluded from future trade in the credit market. We characterize necessary and sufficient conditions for the enforceability of a first-best equilibrium growth path. Weak property rights, impatient producers, and small productivity differentials can make the efficient growth path nonenforceable and lead to an inefficient equilibrium with binding borrowing constraints. For some economies, multiple balanced growth paths coexist.

In answer to the question “Will borrowing constraints necessarily intensify aggregate fluctuations and aggregate cyclical variability?” it has been found that complete markets equilibrium displays aggregate fluctuations that may be dampened when borrowing constraints are introduced. Like others, I find that variability in the distribution of labor productivity shocks amplifies aggregate fluctuations. I also find that allowing agents to have different permanent incomes amplifies aggregate fluctuations, enriching the asset-pricing implications of the complete contingent claims model when demand aggregation is not possible. Although agents are able to equalize their intertemporal marginal rates of substitution (IMRS) of consumption state-by-state, the IMRS of labor is not equalized across agents, creating gains from specialization. To determine how frictions affect aggregate variability, two types of borrowing constraints are studied. In the first model, dividend payments are restricted and, in the second, nonhuman wealth is restricted to be positive. Either type of borrowing constraint can dampen aggregate fluctuations.

I study the bias of actuarially fair measures commonly used to evaluate the impact of a social security system on the well-being of individuals. I investigate how the magnitude of this bias is affected by different features of a pay-as-you-go social security system. Social security affects an individual's welfare in ways other than through its direct effect on her lifetime income. It influences labor and savings decisions and hence factor prices, affecting labor income and the return to savings. Although social security can provide insurance against risk, it can also push borrowing-constrained individuals further away from their optimal consumption paths. I show that, by ignoring these features, actuarially fair measures can grossly misevaluate the impact of social security on the well-being of an individual.