Is there a pessimistic bias in individual beliefs ? Evidence from survey data.

The aim of this paper is to determine whether individuals exhibit a behavioral bias towards pessimism in their beliefs, in a lottery or more generally in an investment opportunities framework. For this purpose, we design a field survey on a sample of 1,540 individuals aiming at deriving a measure of pessimism from answers to hypothetical scenarios. In the context of our experiment, we observe that individuals are on average pessimistic. We analyze how pessimism is distributed among individuals, in particular in link with gender, age and income. We also analyze how our notion of pessimism is related to more general notions of pessimism already introduced in psychology. We finally estimate the possible impact of this pessimistic bias on the financial markets equilibrium risk premium.pessimism; lottery; judged probability;

Hétérogénéité des croyances et équilibre des marchés financiers.

Dans cette thèse, nous proposons de tester une nouvelle explication comportementale de l’énigme de la prime de risque. Ce travail s’appuie sur le modèle avec croyances hétérogènes de Jouini et Napp (2007) selon lequel le pessimisme des investisseurs au niveau agrégé conduit à l’existence de primes de risque très importantes. Dans ce modèle, le pessimisme des agents se traduit par une sous-estimation du taux de rentabilité des actifs : ainsi, alors qu’ils exigent une rémunération du risque identique à celle d’un agent standard, les agents pessimistes surestiment le risque associé aux actifs et la prime de risque qui en résulte est accrue. Les conclusions de ce modèle sont obtenues en l’absence de pessimisme individuel de l’ensemble des agents puisque l’augmentation du prix du risque résulte d’un pessimisme au niveau global qui réside dans la corrélation positive entre optimisme et aversion au risque. Partant de ce constat, nous identifions les conditions dans lesquelles les rentabilités en excès des titres sont cohérentes avec le pessimisme des agents. Nous nous attachons à étudier si la corrélation positive entre optimisme et aversion au risque est obtenue dans le cadre d’une enquête et d’expériences de laboratoire.In this thesis, we propose to test a new behavioral explanation of the equity premium puzzle. This work is based on the heterogeneous beliefs model of Jouini and Napp (2007) according to which, pessimism of investors at the aggregate level leads to very important risk premiums. In this model, agents’ pessimism refers to an underestimation of the average rate of return of assets: while pessimistic agents require a market price of risk identical to the standard agent one, they overestimate the risk associated with assets and the resulting equity premium is therefore increased. There is no need, in this setting, for all investors to be pessimistic. Pessimism at the aggregate level is sufficient in order to ensure an increase in the equity premium. Even if the average belief is neutral, it’s possible to have pessimism at the aggregate level through a positive correlation between optimism and risk aversion. Based on this conclusion, we identify the conditions under which the excess returns of securities are consistent with agents’ pessimism. Our aim is to investigate if there is a positive correlation between optimism and risk aversion through a survey and laboratory experiments.Equilibrium; Risk Aversion; Primes de risques; Rentabilité; Beliefs Heterogeneity;

Are Risk Averse Agents More Optimistic? A Bayesian Estimation Approach

Our aim is to analyze the link between optimism and risk aversion in a subjective expected utility setting and to estimate the average level of optimism when weighted by risk tolerance. This quantity is of particular importance since it characterizes the consensus belief in risk-taking situations with heterogeneous beliefs. Its estimation leads to a nontrivial statistical problem. We start from a large lottery survey (1,536 individuals). We assume that individuals have true unobservable characteristics and that their answers in the survey are noisy realizations of these characteristics. We adopt a Bayesian approach for the statistical analysis of this problem and use an hybrid MCMC approximation method to numerically estimate the distributions of the unobservable characteristics. We obtain that individuals are on average pessimistic and that pessimism and risk tolerance are positively correlated. As a consequence, we conclude that the consensus belief is biased towards pessimism.Bayesian estimation, MCMC scheme, importance sampling, pessimism, risk tolerance, risk aversion, consensus belief

Are Risk Averse Agents More Optimistic? A Bayesian Estimation Approach

Our aim is to analyze the link between optimism and risk aversion in a subjective expected utility setting and to estimate the average level of optimism when weighted by risk tolerance. This quantity is of particular importance since it characterizes the consensus belief in risk-taking situations with heterogeneous beliefs. Its estimation leads to a nontrivial statistical problem. We start from a large lottery survey (1,536 individuals). We assume that individuals have true unobservable characteristics and that their answers in the survey are noisy realizations of these characteristics. We adopt a Bayesian approach for the statistical analysis of this problem and use an hybrid MCMC approximation method to numerically estimate the distributions of the unobservable characteristics. We obtain that individuals are on average pessimistic and that pessimism and risk tolerance are positively correlated. As a consequence, we conclude that the consensus belief is biased towards pessimism.Bayesian estimation, MCMC scheme, importance sampling, pessimism, risk tolerance, risk aversion, consensus belief

Are Risk-Averse Agents more Optimistic? A Bayesian Estimation Approach.

Our aim is to analyze the link between optimism and risk aversion in a subjective expected utility setting and to estimate the average level of optimism when weighted by risk tolerance. Its estimation leads to a non-trivial statistical problem. We start from a large lottery survey (1536 individuals). We assume that individuals have true unobservable characteristics. We adopt a Bayesian approach and use a hybrid MCMC approximation method to numerically estimate the distributions of the unobservable characteristics. We find that individuals are on average pessimistic and that pessimism and risk tolerance are positively correlated.Bayesian Estimation; MCMC Scheme; Importance Sampling; Pessimism; Risk Tolerance; Risk Aversion; Consensus Belief;

Heterogeneous beliefs and equilibrium market models

Dans cette thèse, nous proposons de tester une nouvelle explication comportementale de l’énigme de la prime de risque. Ce travail s’appuie sur le modèle avec croyances hétérogènes de Jouini et Napp (2007) selon lequel le pessimisme des investisseurs au niveau agrégé conduit à l’existence de primes de risque très importantes. Dans ce modèle, le pessimisme des agents se traduit par une sous-estimation du taux de rentabilité des actifs : ainsi, alors qu’ils exigent une rémunération du risque identique à celle d’un agent standard, les agents pessimistes surestiment le risque associé aux actifs et la prime de risque qui en résulte est accrue. Les conclusions de ce modèle sont obtenues en l’absence de pessimisme individuel de l’ensemble des agents puisque l’augmentation du prix du risque résulte d’un pessimisme au niveau global qui réside dans la corrélation positive entre optimisme et aversion au risque. Partant de ce constat, nous identifions les conditions dans lesquelles les rentabilités en excès des titres sont cohérentes avec le pessimisme des agents. Nous nous attachons à étudier si la corrélation positive entre optimisme et aversion au risque est obtenue dans le cadre d’une enquête et d’expériences de laboratoire.In this thesis, we propose to test a new behavioral explanation of the equity premium puzzle. This work is based on the heterogeneous beliefs model of Jouini and Napp (2007) according to which, pessimism of investors at the aggregate level leads to very important risk premiums. In this model, agents’ pessimism refers to an underestimation of the average rate of return of assets: while pessimistic agents require a market price of risk identical to the standard agent one, they overestimate the risk associated with assets and the resulting equity premium is therefore increased. There is no need, in this setting, for all investors to be pessimistic. Pessimism at the aggregate level is sufficient in order to ensure an increase in the equity premium. Even if the average belief is neutral, it’s possible to have pessimism at the aggregate level through a positive correlation between optimism and risk aversion. Based on this conclusion, we identify the conditions under which the excess returns of securities are consistent with agents’ pessimism. Our aim is to investigate if there is a positive correlation between optimism and risk aversion through a survey and laboratory experiments.ou

Is there a pessimistic bias in individual and collective beliefs ? Theory and Evidence

Voir les documents : 1)Consensus Consumer and Intertemporal asset pricing with Heterogeneous Beliefs - http://basepub.dauphine.fr/xmlui/handle/123456789/78, 2) Is there a pessimistic bias in individual beliefs? Evidence from survey data - http://basepub.dauphine.fr/xmlui/handle/123456789/1051ou

Are risk agents more optimistic? A Bayesian estimation approach

International audienc

Are Risk Averse Agents More Optimistic? A Bayesian Estimation Approach

International audienceOur aim is to analyze the link between optimism and risk aversion in a subjective expected utility setting and to estimate the average level of optimism when weighted by risk tolerance. This quantity is of particular importance since it characterizes the consensus belief in risk-taking situations with heterogeneous beliefs. Its estimation leads to a nontrivial statistical problem. We start from a large lottery survey (1,536 individuals). We assume that individuals have true unobservable characteristics and that their answers in the survey are noisy realizations of these characteristics. We adopt a Bayesian approach for the statistical analysis of this problem and use an hybrid MCMC approximation method to numerically estimate the distributions of the unobservable characteristics. We obtain that individuals are on average pessimistic and that pessimism and risk tolerance are positively correlated. As a consequence, we conclude that the consensus belief is biased towards pessimism