This paper considers a sequence of discrete-time random walk markets with a single risky asset, and gives conditions for the existence of arbitrage opportunities or free lunches with vanishing risk, of the form of waiting to buy and selling the next period, with no shorting, and furthermore for...

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)....

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...

Maximum drawdown refers to the largest cumulative loss of a portfolio within a given time interval. While it has been used by investment professionals as an important measure of portfolio risk for many years, its nature and its implications for asset pricing have not been well understood. The...

The portfolio separating distribution is sufficient and necessary for a preference-free optimal choice only if the solution is assumed to be constant a priori. The portfolio separating condition is generalized. The new distribution class allowing for correlation uncertainty is defined as...

We use the Bayesian method introduced by Gallant and McCulloch (2009) to estimate consumption-based asset pricing models featuring smooth ambiguity preferences. We rely on semi-nonparametric estimation of a flexible auxiliary model in our structural estimation. Based on the market and aggregate...

We develop and implement methods for determining whether introducing new securities or relaxing investment constraints improves the investment opportunity set for prospect investors. We formulate a new testing procedure for prospect spanning for two nested portfolio sets based on subsampling and...

This paper extends the notion of variance optimal hedging of contingent claims under the incomplete market setting to the hedging of entire processes, and applies the results to the problem of tracking stock indices. Sufficient conditions under which this is possible are given, along with the...

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...