Solving OLG Models with Many Cohorts, Asset Choice and Large Shocks

The paper presents a computationally efficient method to solve overlapping generations models with asset choice. The method is used to study an OLG economy with many cohorts, up to 3 different assets, stochastic volatility, short-sale constraints, and subject to rather large technology shocks. On the methodological side, the main findings are that global projection methods with polynomial approximations of degree 3 are sufficient to provide a very precise solution, even in the case of large shocks. Globally linear approximations, in contrast to local linear approximations, are sufficient to capture the most important financial statistics, including not only the average risk premium, but also the variation of the risk premium over the cycle. However, global linear approximations are not sufficient to reliably pin down asset choices. With a risk aversion parameter of only 4, the model generates a price of risk, measured as the Sharpe ratio, that is almost half of what it is for US stocks. However, the asset price fluctuations and the equity premium are much smaller than in US data

Demand Induced Fluctuations

We build a variation of the neoclassical growth model in which households increased desire to save generate recessions. Our economy features three departures from the standard model: (1) goods markets (for nontradables) require active search from households wherein increases in consumption expenditures increase measured productivity; (2) adjustment costs make it difficult to expand the tradable goods sector by reallocating factors of production from nontradables to tradables; (3) labor markets have Nash bargaining wage setting and Mortensen-Pissarides search and matching frictions labor markets. These departures provide a novel quantitative theory to explain recessions like those in southern Europe without relying on technology shocks

Sticky Wage Models and Labor Supply Constraints

In sticky wages models (either à la Calvo or à la Rotemberg), labor is solely determined by the demand side. However, a change of circumstances may make labor demand higher than agents' willingness to work. We find that workers are required to work against their will between 15 percent and 30 percent of the time (with 5 percent wage markup, less with higher markups and in Rotemberg models). Estimating models with the minimum of the demand and supply of labor instead of the demand-determined quantity yields different and unappealing properties. Hence, special attention should be paid to possible violations of the labor supply constraint