This chapter of a collective book aims at presenting the basics of decision making under risk. We first define notions … of risk and increasing risk and recall definitions and classifications (that are valid independently of any … representation) of behavior under risk. We then review the classical model of expected utility due to von Neumann and Morgenstern …

The theory of existence of equilibrium with short-selling is reconsidered under risk and ambiguity modelled by risk … of the risk adjusted sets of expectations overlap. This condition is necessary if agents are not risk neutral at extreme … compatible trades, with non negative expected value with respect to any risk adjusted prior, strictly positive for some agent and …

, which allow to take into account observed behaviors as in Allais' paradox under risk or Ellsberg's paradox under uncertainty … uncertainty, and Quiggin and Yaari under risk, succeeded to characterize preferences which generalize the EU model, by means of a … for more diversified patterns of behavior under uncertainty as well under risk. …

, with a short maturity or indexed. It analyses empirically the determinants of these risk sources separately, developing a … risk. Only inflation impacts all types of risky debt, underscoring the overarching importance of monetary credibility to …

An unfunded Social Security system faces the major risk, sometimes referred to as "political risk", that future … generations modify or even suppress the contributions. In order to account properly for this risk, the paper considers a political … the economy. The impact of various factors -intra-generational redistribution, risk aversion, financial markets …

-agricultural sector is considered as a risk-mitigating strategy by rural Pakistani households. This issue has already been addressed but … whether ex ante engagement in the non-agricultural sector is partly motivated by a desire to mitigate risk. The main feature …

We define a coherent risk measures as set-valued maps satisfying some axioms. We show that this definition is a … convenient extension of the real-valued risk measures introduced by Artzner, Delbaen, Eber and Heath (1998). We then discuss the … aggregation issue, i.e. the passage from valued random portofolio to valued measure of Risk. Necessary and sufficient conditions …

-to-implement procedure could be adequately used. For that purpose, the subjects' degree of risk aversion is compared across three payment …