This paper augments the neoclassical growth model to study the macroeconomic effects of idiosyncratic investment risk. The general equilibrium is solved in closed form under standard assumptions for preferences and technologies. A simple condition is identified for incomplete markets to result...

We consider a class of convex, competitive, neoclassical economies in which agents are rational; the equilibrium is unique; there is no room for randomization devices; and there are no shocks to preferences, technologies, endowments, or other fundamentals. In short, we rule out every known source...