This study develops and implements a theory and method for analyzing whether introducing new securities or relaxing investment constraints improves the investment opportunity set for risk averse investors. We develop a test procedure for ‘stochastic spanning’ for two nested polyhedral...

The term “equity premium puzzle” was coined in 1985 by economists Rajnish Mehra and Edward C. Prescott. The equity premium puzzle in considered one of the most significant questions in finance. A number of papers have explored the fundamental questions of why the premium exists and has not...

I study the effects of risk and ambiguity (Knightian uncertainty) on optimal portfolios and equilibrium asset prices when investors receive information that is difficult to link to fundamentals. I show that the desire of investors to hedge ambiguity leads to portfolio inertia and excess...

I study the effects of aversion to risk and ambiguity (uncertainty in the sense of Knight (1921)) on the value of the market portfolio when investors receive public information that they find difficult to link to fundamentals and hence treat as ambiguous. I show that small changes in public...

The paper investigates the role of the Intertemporal Elasticity of Substitution (IES ) in determining the equity premium. This is done in an overlapping generations economy populated by agents that live for 2 periods and maximize a Kihlstrom-Mirman expected utility function. The equity premium...

We generalize the long-run risks (LRR) model in Bansal and Yaron (2004) by incorporating the recursive smooth ambiguity aversion preferences of Klibanoff, Marinacci, and Mukerji (2005, 2009) and time-varying ambiguity. Relative to the Bansal-Yaron model, the generalized LRR model remains...

We propose a novel one-sector stochastic growth model, where producitivity growth follows a Markov-switching process with two regimes, and where households have generalized recursive smooth ambiguity preferences. The adopted class of preferences permits a three-way separation of risk aversion,...

I develop a stochastic growth model with production where there is a hidden state governing productivity growth regimes, and the hidden state evolves according to a Markov chain. Economic agents learn about the hidden state and display ambiguity aversion in the spirit of Klibanoff et al. (2005)....