Based on a multisector general equilibrium framework, we show that the sectoral elasticity of substitution plays the key role in the evolution of asymmetric tails of macroeconomic fluctuations and the establishment of robustness against productivity shocks. A non-unitary elasticity of substitution renders a nonlinear Domar aggregation, where normal sectoral productivity shocks translate into non-normal aggregated shocks with variable expected output growth. We empirically estimate 100 sectoral elasticities of substitution, using the time-series linked input-output tables for Japan and find that the production economy is elastic overall, relative to a Cobb-Douglas economy with unitary elasticity. In addition to the previous assessment of an inelastic production economy for the USA, the contrasting tail asymmetry of the distribution of aggregated shocks between the USA and Japan is explained. Moreover, the robustness of an economy is assessed by expected output growth, the level of which is led by the sectoral elasticities of substitution under zero-mean productivity shocks.

This paper studies the macroeconomic effects of shocks to idiosyncratic business risk in an economy with endogenously incomplete markets. I develop a model in which firms face idiosyncratic risk and obtain insurance from intermediaries through contracts akin to credit lines. Insurance is imperfect due to limited commitment in financial contracts. Although steady-state capital is higher than if firms were constrained to issue only standard equity, a rise in uncertainty about idiosyncratic business outcomes leads to an endogenous reduction in risk sharing. This deterioration in risk sharing results from a general-equilibrium shortage of pledgeable assets and implies that the economy’s response to an increase in idiosyncratic business risk can be amplified by financial contracting rather than dampened. In a parametrized version of the model, a rise in idiosyncratic business risk generates a large increase in uncertainty about aggregate investment.

This paper introduces imperfect knowledge and learning behavior of economic agents into the Kiyotaki and Moore model and studies the interaction of agents' collateral price beliefs, collateral constraint, and aggregate economic activity over the business cycle. It establishes the E-stability condition and the convergence of the real time learning process. In addition, it shows that learning strengthens the role of collateral constraints in aggregate fluctuations.

We investigate the quantitative behavior of business-cycle models in which the intermediation process acts either as a source of fluctuations or as a propagator of real shocks. In neither case do we find convincing evidence that the intermediation process is an important element of aggregate fluctuations. For an economy driven by intermediation shocks, consumption is not smoother than output, investment is negatively correlated with output, variations in the capital stock are quite large, and interest rates are procyclical. The model economy thus fails to match unconditional moments for the U.S. economy. We also structurally estimate parameters of a model economy in which intermediation and productivity shocks are present, allowing for the intermediation process to propagate the real shock. The unconditional correlations are closer to those observed only when the intermediation shock is relatively unimportant.