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2020, Physica A: Statistical Mechanics and its Applications
In the paper there is studied an optimal saving model in which the interest-rate risk for saving is a fuzzy number. The total utility of consumption is defined by using a concept of possibilistic expected utility. A notion of possibilistic precautionary saving is introduced as a measure of the variation of optimal saving level when moving from a sure saving model to a possibilistic risk model. A first result establishes a necessary and sufficient condition that the presence of a possibilistic interest-rate risk generates an extra-saving. This result can be seen as a possibilistic version of a Rothschilld and Stiglitz theorem on a probabilistic model of saving. A second result of the paper studies the variation of the optimal saving level when moving from a probabilistic model (the interest-rate risk is a random variable) to a possibilistic model (the interest-rate risk is a fuzzy number).
Panoeconomicus, 2017
This paper proposes two mixed models to study a consumer?s optimal saving in the presence of two types of risk: income risk and background risk. In the first model, income risk is represented by a fuzzy number and background risk by a random variable. In the second model, income risk is represented by a random variable and background risk by a fuzzy number. For each model, three notions of precautionary savings are defined as indicators of the extra saving induced by income and background risk on the consumer?s optimal choice. In conclusion, we can characterize the conditions that allow for extra saving relative to optimal saving under certainty, even when a certain component of risk is modelled using fuzzy numbers.
Ijimai, 2013
In this paper we study the optimal saving problem in the framework of possibility theory. The notion of possibilistic precautionary saving is introduced as a measure of the way the presence of possibilistic risk (represented by a fuzzy number) influences a consumer in establishing the level of optimal saving. The notion of prudence of an agent in the face of possibilistic risk is defined and the equivalence between the prudence condition and a positive possibilistic precautionary saving is proved. Some relations between possibilistic risk aversion, prudence and possibilistic precautionary saving were established.
Axioms, 2020
This paper studies an optimal saving model in which risk is represented by a fuzzy number and the total utility function of the model is defined by an expected utility operator. This model generalizes some existing possibilistic saving models and from them, by a particularization, one can obtain new saving models. In the paper, sufficient conditions are set for the presence of potential risk to increase optimal saving levels and an approximation formula for optimal saving is demonstrated. Particular models for a few concrete expected utility operators are analyzed for triangular fuzzy numbers and CRRA-utility functions.
Economics Letters, 2015
• We find a new sufficient condition for precautionary saving under two risks. • We provide three economic interpretations for this condition. • An interpretation focuses on the marginal effect of saving on total income variance. • An interpretation focuses on the covariance between total income and saving returns. • An interpretation focuses on the effect of saving on the utility premium.
The GENEVA Papers on Risk and Insurance- …, 1992
We adopt the multivariate non-expected utility approach proposed by Yaari [1986] to provide a characterization of the comparative statics effects of greater risk aversion and of mean-preserving increases in risk on saving and borrowing in the presence of income and interest rate risk. We show that in Yaari's model, it is possible to extend the applicability of the Diamond and Stiglitz [1974] and Kihlstrom and Mirman [1974] (DSKM) single-crossing property to establish a relationship between greater risk aversion and saving (or borrowing) on the basis of the individual's ordinal preferences as long as the two risks are independent. We also demonstrate that the comparative statics effects of a joint mean-preserving increase in random income and interest rate on saving and borrowing can be determined by an extension of the DSKM single-crossing property.
Fuzzy Sets and Systems, 2009
Risk theory is usually developed within probability theory. The aim of this paper is to propose an approach of the risk aversion by possibility theory, initiated by Zadeh in 1978. The main notion studied in this paper is the possibilistic risk premium associated with a fuzzy number A and a utility function u. Under the hypothesis that the utility function u verifies certain hypotheses, one proves a formula to evaluate the possibilistic risk premium in terms of u and of some possibilistic indicators.
Economics Letters, 1988
proved that within the anticipated utility framework, a risk averse decision maker will have precautionary saving regardless of the sign of the third derivative of his utility function. In this note we extend (a modification of) this result for an n-period model.
Soft Computing, 2010
In this paper a possibilistic model of risk aversion based on the lower and upper possibilistic expected values of a fuzzy number is studied. Three notions of possibilistic risk premium are defined for which calculation formulae in terms of Arrow–Pratt index and a possibilistic variance are established. A possibilistic version of Pratt theorem is proved.
2008 First International Conference on Complexity and Intelligence of the Artificial and Natural Complex Systems. Medical Applications of the Complex Systems. Biomedical Computing, 2008
This paper is concerned with an approach of risk aversion by possibility theory. We introduce and study new possibilistic risk indicators.The main notions are the possibilistic risk premium and the possibilistic relative risk premium associated with a fuzzy number and a utility function. We also give formulae for computing them.
2012
In the traditional treatment, risk situations are modeled by random variables. This paper focuses on risk situations described by fuzzy numbers. The goal of the paper is to define and characterize possibilistic risk aversion and study some of its indicators.
Journal of Economics, 2022
We study precautionary saving in a two-period model that allows for nonlinear risks and nonseparable preferences. Permitting nonlinear risk effects is important because they are common in the developing world or when worldwide shocks hit economies, like the COVID-19 pandemic. Allowing nonseparable preferences is also important because they admit the incorporation of intergenerational transfer, habit persistence and other specific features of intertemporal decision making. We decompose the risk shock using Davis's (Int Econ Rev 30(1):131-136, 1989) compensation method and analyze the income and substitution effect of an increase in risk. We prove that the substitution effect is always negative and, therefore, the income effect must be positive and larger in size to have a precautionary net effect. We then apply the method to various sources of risk, such as income, interest rate and wealth risk. We analyze the magnitude of each effect and find the conditions required to guarantee precautionary saving in each case. Our results are presented as signs of covariances, which provides a new perspective on precautionary saving. Keywords Precautionary saving Á Nonlinear risk Á Nonseparable preferences Á Increases in risk Á Mean-preserving spreads JEL Classification E21 Á D81 Á D11
Economics Letters, 2010
Risk may induce precautionary saving but it can also reduce saving. The theoretical literature recognizes both possibilities, but favors a positive effect (both for developed and developing countries); the empirical literature is divided, reporting (small) positive effects for developed economies and (large) negative effects for developing countries. We show in a 2-period model how the effect of risk on savings depends not only on preferences but also on the type of risk.
Fuzzy Sets and Systems, 2016
In this paper, we generalize classical results on risk aversion by analyzing the case, when the available data about cash flows are fuzzy numbers, random fuzzy numbers, type-2 fuzzy sets, random type-2 fuzzy sets etc. We prove that the Arrow-Pratt measures are also risk aversion measures when an agent measures her risk using the Jensen-type operators. We also provide numerous examples of the Jensen-type operators.
Economics Bulletin, 2007
The aim of this note is to suggest that prudence, i.e. convexity of marginal utility, can only explain a small share of precautionary savings, which we may define as savings generated by variance in income. Therefore, if we are willing to admit that precautionary savings constitute a sizable share of total savings, other factors should be called for. We present a few examples showing that risk aversion might constitute one such factor.
German Economic Review, 2005
This paper develops a model of personal saving that includes, unlike previous models appearing in the literature, an explicit role for the Leland-Kimball measure of prudence. Estimation of the model using Bank of Italy survey data suggests that a large share of total saving is driven by precautionary reasons.
Journal of Monetary Economics, 2008
This paper examines how stochastic changes in risk a¤ect the demand for saving. We consider two models of savings demand: one in which future labor income is risky and one in which the return on savings is risky. In each model, we examine the e¤ects of an N th-degree stochastic change in the risk. For each case, we establish necessary and su¢ cient conditions on preferences that will guarantee that the individual increases his or her level of savings. We show how in the case of only labor income risk, any changes in savings are purely due to precautionary savings motives. For the case where the return on savings is risky, we show how both a precautionary e¤ect and a substitution e¤ect need to be analyzed.
Economics Letters, 2014
2020
We study precautionary saving in a two-period model using Davis’s(1989) compensation method, which allows a separation between income and substitution effect when the decision maker faces an increase in risk. We prove that the substitution effect is always negative and therefore, the income effect must then be positive and larger in size to have an increase in saving or a precautionary effect. We then apply the method to different sources of risks like income, interest rate and wealth risk and analyze the magnitude of each effect and find the conditions required to guarantee precautionary saving in each case. We observe that when the utility function is time separable, the conditions to have precautionary effect are the ones we know from the literature. However, our more general setting allows for the possibility of non-linear risk effects. Our results are presented as signs of covariances, which provide a new perspective on the issue of precautionary saving. The authors acknowledge...
2019
The article is devoted to risk modeling in prudent operators or investors, whose decisions are characterized by a trade-off between loss risk and reproduction function. Their attitude may be covered by the combined use of quantitative risk measures. Show the approach to risk modeling, which we will move to the traditional theory of maximizing the possibility of using service functions. Investors who engage their capital are always at risk because they make changes in the structure of their assets when investing. The risk of investing is identified with a possible threat or chance of achieving the expected benefits and is associated with the risk of an investment effect not being expected. This effect may be worse or better than previously assumed. The need to identify and verify the risk results from the possibility of achieving the expected benefits of the investor or avoiding losses. When making investment decisions, we can distinguish three types of investor behavior: Preference for risk and its effects (gambler)the investor makes decisions even when the probability of loss exceeds the probability of profit. The investor is willing to incur higher expenses in order to make a decision about a higher risk. Risk neutrality-the investor does not make decisions when the probability of making a profit is too low. When making decisions, the investor does not pay attention to the amount of risk. Risk aversion-the investor expects the probability of profit to be greater than loss. An investor takes a risk when he expects to receive bonus compensation. Risk aversion also depends on the investor's resources. The richer the investor, the easier it will be for him to accept the loss. The models described in the article assume that investors act rationally and are characterized by risk aversion.
Journal of Economic Dynamics and Control, 1998
This paper considers the problem of precautionary savings for an expected utility specification with finite horizon. The exact solution is known for only a few cases. Numerical methods have limited applications because of Bellman's 'curse of dimensionality'. This paper derives a simple analytical approximate solution for a general specification of the felicity function which is linear in the variance of the innovations on human wealth. Numerically, the approximation is very accurate for realistic values of the parameters of the problem.
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