With a focus on risk, classical portfolio theory assumes that probabilities of future outcomes are known. In reality, however, there is ambiguity in these probabilities. This paper studies the nature of the relationship between risk and ambiguity and proves that in most cases ambiguity cannot be...

Asset pricing models assume that probabilities of future outcomes are known. In reality, however, there is ambiguity with regard to these probabilities. Accounting for ambiguity in asset pricing theory results in a model with two systematic components, beta risk and beta ambiguity. The focus of...

With a focus on risk, classical portfolio theory assumes that probabilities of future outcomes are known. In reality, however, there is ambiguity in these probabilities. This paper studies the nature of the relationship between risk and ambiguity and proves that in most cases ambiguity cannot be...

There are two phenomena in behavioral finance and economics which are seemingly unrelated and have been studied separately; overconfidence and ambiguity aversion. In this paper we are trying to link these two phenomena providing a theoretical foundation supported by evidence from an experimental...

Ellsberg (1961) proposes two alternative frames to elicit individuals' preferences for ambiguity. Through an experiment, we find that Ellsberg's three-color one-urn frame induces very different revealed preferences than the two-color two-urn frame. In both frames, we document ambiguity aversion...

We study the effect of ambiguity — Knightian uncertainty — on payout policy. We find that firm-level ambiguity increases and accelerates payout, via both dividends and share repurchases. This positive effect of ambiguity is distinct from the known negative effect of risk on payout policy....

This paper introduces a model of decision making under ambiguity by extending the Bayesian approach to uncertain probabilities. In this model, preferences for ambiguity pertain directly to probabilities such that attitude toward ambiguity is defined as attitude toward mean-preserving spreads in...

We introduce ambiguity in conjunction with risk to study the relation between risk, ambiguity, and expected returns. Distinguishing between ambiguity and attitudes toward ambiguity, we develop an empirical methodology for measuring the degree of ambiguity and for assessing attitudes toward...

The new issues market is used to examine the impact of ambiguity and ambiguity aversion on the pricing of financial assets. An IPO process is modeled assuming ambiguity regarding the returns on financial assets and risk and ambiguity aversion on the part of agents. Theoretically, the underwriter...