We analyse questions of arbitrage in financial markets in which asset prices change in time as stationary stochastic processes. The main focus of the paper is on a model where the price vectors are independent and identically distributed. In the framework of this model, we find conditions that...

We study the relation between order imbalance and past returns and firm characteristics and test a number of hypothesis including the disposition effect, momentum and contrarian trading, taxloss selling and flight-to-quality hypothesis. These hypotheses make predictions about investors’ buy or...

Ambiguity aversion in dynamic models is motivated by the presence of unknown time-varying features, which agents do not understand and cannot theorize about. We analyze the consequences of this assumption for economic agents and model builders, who typically need to estimate a model, e.g., to...

Estimates of agents' risk aversion dier between market studies and experimental studies. We demonstrate that the estimates can be reconciled through consistent treatment of agents' tendency for narrow framing, regarding integration of background wealth as well as across risky outcomes: Risk...

In this paper we examine the effect of collateral requirements on the prices of long- lived assets. We consider a Lucas-style infinite-horizon exchange economy with hetero- geneous agents and collateral constraints. There are two trees in the economy which can be used as collateral for...

Agents with cognitive limitations may compute the expected value of a risky asset incorrectly. If market prices reflect the probabilities of the payoff-relevant states, agents who compute the probabilities incorrectly encounter a market price that is inconsistent with their calculation. We test...

We study the existence of equilibria with endogenously complete markets in a continuous-time, heterogenous agents economy driven by a multidimensional diffusion process. Our main results show that if prices are real analytic as functions of time and the state variables of the model then a suffi-...

We derive representations for the stock price drift and volatility in the equilibrium of agents with arbitrary, heterogeneous utility functions and with the aggregate dividend following an arbitrary Markov diffusion. We introduce a new, intrinsic characteristic of the aggregate dividend process...

Many tests of asset pricing models address only the pricing predictions — but these pricing predictions rest on portfolio choice predictions which seem obviously wrong. This paper suggests a new approach to asset pricing and portfolio choices, based on unobserved heterogeneity. This approach...