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...

In 1995, Benartzi and Thaler introduced the concept myopic loss aversion to explain the equity premium puzzle. They provided empirical evidence to support their arguments. Recently, Durand, et al. criticized this empirical analysis. They propose an approach which not only rejects the...

We propose Keynesian utilities as a new class of non-expected utility functions representing the preferences of investors for optimism, defined as the composition of the investor's preferences for risk and her preferences for ambiguity. The optimism or pessimism of Keynesian utilities is...

We show in a simple framework that momentum trading can exist in equilibrium and momentum trading is profitable. Properties of the model fit the empirics well. First, the model captures in a parsimonious manner both short-term overreaction and long-term reversals. Second, it predicts that...

Using a novel and direct measure of investor sentiment, I find that Facebook's Gross National Happiness (GNH) has the ability to predict changes in both daily returns and trading volume in the US stock market. For instance, an increase of one standard deviation in GNH is associated with an...

To understand how real investors use their beliefs and preferences in investing decisions, we examine a panel survey of self-directed online investors at a UK bank. The survey asks for return expectations, risk expectations, and risk tolerance of these investors in three-month intervals between...

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...