Concave hiring rules imply that firms respond more to bad shocks than to good shocks. They provide a unified explanation for several seemingly unrelated facts about employment growth in macro and micro data. In particular, they generate countercyclical movement in both aggregate conditional...

We survey literature on ambiguity with an emphasis on recent applications in macroeconomics and finance. Like risk, ambiguity leads to cautious behavior and uncertainty premia in asset markets. Unlike risk, ambiguity can generate first order welfare losses. As a result, precautionary behavior...

This paper estimates a business cycle model with endogenous financial asset supply and ambiguity averse investors. Firms' shareholders choose not only production and investment, but also capital structure and payout policy subject to financial frictions. An increase in uncertainty about profits...

This paper considers a consumption-based asset pricing model where housing is explicitly modeled both as an asset and as a consumption good. Nonseparable preferences describe households' concern with composition risk, that is, fluctuations in the relative share of housing in their consumption...

We show that in the formalization of representativeness (Kahneman and Tversky (1972)) developed by Gennaioli and Shleifer (2010), overreaction and confidence are affected by uncertainty, as a news effect interacts with an uncertainty effect. In the time series domain, this interaction emerges in...

We reinterpret post World War II US economic history using an estimated microfounded model that allows for changes in the monetary/fiscal policy mix. We find that the fiscal authority was the leading authority in the '60s and the '70s. The appointment of Volcker marked a change in the conduct of...