We investigate the effects of collateral and monetary policy on economic growth within a Ramsey equilibrium model where agents have different discount factors. Introducing liquidity constraints in segmented markets where (poor) impatient agents without collateral have limited access to credit, we study their implications in terms of welfare and business cycles (based on deterministic cycles through bifurcations and self-fulfilling prophecies). We find that an accommodative monetary policy may be growth-enhancing and welfare-improving (through the inequality reduction) while making unpleasant fluctuations more likely. Conversely, a regulation reinforcing the role of collateral and tempering the financial market imperfections may stimulate the economic growth while pursuing the goal of stabilization.

We analyze local indeterminacy and sunspot-driven fluctuations in the standard two-sector model with additively separable preferences. We provide a detailed theoretical analysis enabling us to derive relevant bifurcation loci and to characterize the steady-state local stability properties as a function of various structural parameters influencing the degree of increasing returns to scale, the amount of intertemporal substitution in consumption, and the elasticity of the aggregate labor supply curve. On the theoretical side, we prove the existence of both a flip and a Hopf bifurcation locus in the corresponding parameter space. We also show that local indeterminacy can be obtained under any labor supply elasticity or under an arbitrarily low elasticity of intertemporal substitution in consumption. On the empirical side, we find that indeterminacy and sunspot fluctuations are robust features of two-sector models, prevailing for most empirically plausible calibrations for these parameters. (This abstract was borrowed from another version of this item.)

Imposing some constraints on public debt is often justified regarding sustainability and stability issues. This is especially the case when the ratio of public debt over GDP is restricted to be constant. Using a Ramsey model, we show that such a constraint can however be a fundamental source of indeterminacy, and therefore, of expectations-driven fluctuations. Indeed, through the intertemporal budget constraint of the government, income taxation negatively depends on future debt, i.e. on the expected level of production. This mechanism ensures that expectations on the future tax rate may be self-fulfilling. We show that this is promoted by a larger ratio of debt over GDP.

We introduce public debt in a Ramsey model with heterogenous agents and a public spending externality affecting utility which is financed by income tax and public debt. We show that public debt considered as a fixed portion of GDP can have a stabilizing or destabilizing effect depending on some fundamental elasticities. When the public spending externality is weak and the elasticity of capital labor substitution is low enough, public debt can only be destabilizing, generating damped or persistent macroeconomic fluctuations. Whereas when the public spending externality and the elasticity of capital labor substitution are strong enough, public debt can be stabilizing, driving to monotone convergence an economy experiencing damped or persistent fluctuations without debt.