This paper examines green alliances between environmental groups (EGs) and polluting firms, which have become more common in the last decades, and analyzes how they affect policy design. We first show that the activities of regulators and EGs are strategic substitutes, giving rise to free-riding incentives on both agents. Nonetheless, the presence of the EG yields smaller welfare benefits when firms are subject to regulation than when they are not. In addition, the introduction of environmental policy yields large welfare gains when the EG is absent but small benefits when the EG is already present.

Using a two-sector endogenous growth model, the speed of convergence is determined primarily by the gap in rates of return between physical and human capital. In closed economies, for a typical situation of having relatively less physical capital than in a steady state, the return on physical capital will be significantly high, whereas the return on human capital will be relatively low. This gap in rates of return is quite large when the economy is not at its steady state. In open economies, where human capital is nontradable, the gap in rates of return is small, as is the gap between the international interest rate (which is less than the closed economies return on physical capital) and the return on human capital. Convergence in open economies will be relatively slow, and convergence in closed economies will be relatively fast, and therefore there is little gain from financial liberalization.

Stochastic models with economywide shocks imply that the welfare costs of aggregate volatility are negligible. Empirical evidence suggests that the volatility of idiosyncratic shocks is several times that of aggregate shocks. This paper introduces both types of shocks. We find that if in the process of eliminating aggregate risk the policymaker can reduce idiosyncratic risk by an amount suggested by available empirical evidence, the welfare gains from stabilization can become significant. The introduction of idiosyncratic risk has important implications for asset pricing, and in particular may reduce the risk-free rate substantially, through the precautionary savings motive. Many of our results are sensitive both to the degree of risk aversion and to the flexibility of labor supply. The paper highlights the trade-offs involved in analyzing the effects of risk on growth and welfare and on asset pricing, clarifying the need to examine these issues within a unified stochastic general equilibrium framework.