Precautionary Saving and Consumption Smoothing across Time and Possibilities

This paper examines how aversion to risk and aversion to intertemporal substitution determine the strength of the precautionary saving motive in a two-period model with Selden/Kreps–Porteus preferences. For small risks, we derive a measure of the strength of the precautionary saving motive that generalizes the concept of "prudence" introduced by Kimball (1990b) . For large risks, we show that decreasing absolute risk aversion guarantees that the precautionary saving motive is stronger than risk aversion, regardless of the elasticity of intertemporal substitution. Holding risk preferences fixed, the extent to which the precautionary saving motive is stronger than risk aversion increases with the elasticity of intertemporal substitution. We derive sufficient conditions for a change in risk preferences alone to increase the strength of the precautionary saving motive and for the strength of the precautionary saving motive to decline with wealth. Within the class of constant elasticity of intertemporal substitution, constant-relative risk aversion utility functions, these conditions are also necessary.     

Risk Aversion Revisited

In order to supply additional empirical evidence of the effect of wealth on relative risk aversion, this study investigates households' demand for risky assets, using analysis of covariance techniques applied to the asset holdings of Canadian individual households. The extent and pattern of life-cycle effects are also examined. Results generally point to decreasing relative risk aversion when housing is either excluded from the definition of wealth or treated as a riskless asset. The investor's life-cycle plays a prominent role in portfolio selection behavior, with risk aversion increasing uniformly with age. Tax differentials do not seem to be an important element in investment decisions with respect to risk. When the sample and wealth definitions are censored in order to approximate those of previous empirical studies, their findings on relative risk aversion are generally corroborated.     

A Note on Risk Aversion,Prudence and Portfolio Insurance

This paper examines some properties of portfolio insurance that are linked to the risk aversion and the prudence of the investor. We provide explicit conditions to measure portfolio sensitivity to downside risk. We also characterize the degree of portfolio insurance by means of the ratio of absolute prudence to absolute risk aversion.     

Beyond Risk Aversion: Why,How and What's Next?

Risk attitudes other than risk aversion (e.g. prudence and temperance) are becoming important both in theoretical and empirical work. While the literature has mainly focused its attention on the intensity of such risk attitudes (e.g. the concepts of absolute prudence and absolute temperance), I consider here an alternative approach related to the direction of these attitudes (i.e. the sign of the successive derivatives of the utility function).     

Markets versus governments

We provide a simple framework for comparing market allocations with government-regulated allocations. Governments can collect information about individuals’ types and enforce transfers across individuals. Markets (without significant government intervention) have to rely on transactions that are ex post beneficial for individuals. Consequently, governments achieve better risk sharing and consumption smoothing than markets. However, politicians in charge of collective decisions can use the centralized information and the enforcement power of government for their own benefits. This leads to political economy distortions and rents for politicians, making government-operated allocation mechanisms potentially worse than markets. We provide conditions under which it is ex ante beneficial for the society to tolerate the political economy distortions in exchange for the improvement in risk sharing. For example, more effective controls on politicians or higher discount factors of politicians make governments more attractive relative to markets. Moreover, when markets cannot engage in self-enforcing risk-sharing arrangements and income effects are limited, greater risk aversion and greater uncertainty make governments more attractive relative to markets. Nevertheless, we also show theoretically and numerically that the effect of risk aversion on the desirability of markets may be non-monotonic. In particular, when markets can support self-enforcing risk-sharing arrangements, a high degree of risk aversion improves the extent of risk sharing in markets and makes governments less necessary. The same pattern may also arise because of “income effects” on labor supply. Consequently, the welfare gains of governments relative to markets may have an inverse U-shape as a function of the degree of risk aversion of individuals.     

Prudence, Demand Uncertainty, Background Risk, and the Law of Supply: A Nonexpected Utility Approach to the Firm

We identify two motives, prudence and risk aversion, which give rise to precautionary behavior for a quantity- or price-setting monopolist facing demand uncertainty who has dual theoretic preferences. We also analyze a piecewise linear profit function due to a tax on profits that varies with the profit level. We show that the comparative statics of greater risk (mean-preserving spread and mean-utility preserving spread) can be totally or partially determined by the Diamond-Stiglitz and Kihlstrom-Mirman single-crossing property. For example, for a prudent risk-averse quantity-setting dual theoretic monopolist, a mean-preserving spread will have the same impact on output under uncertainty as a fall in the state of demand under certainty. Finally, we find that, in contrast to expected utility, a stochastically larger state of demand (first-order stochastic dominance) will raise output even if background risk is present.     

Does better information about foreign shocks improve monetary policy?

This paper examines whether better information about foreign shocks leads to welfare-improving monetary policy using a stylised two-country New Keynesian general equilibrium model. We demonstrate that when terms of trade externality exist and national central banks have the incentives to shift terms of trade in their own favour, the equilibrium under imperfect information may be welfare superior relative to an equilibrium with perfect information. In addition, the welfare gains or losses from information sharing between central banks are found to be small for empirically plausible range of parameters for risk aversion and elasticity of labour supply.     

The Spillover effect of compulsory insurance

The assumption usually made in the insurance literature that risks are always insurable at the desired level does not hold in the real world: some risks are not—or are only partially—insurable, while others, such as civil liability or health and workers' injuries, must be fully insured or at least covered for a specific amount. We examine in this paper conditions under which a reduction in the constrained level of insurance for one risk increases the demand of insurance for another independent risk. We show that it is necessary to sign the fourth derivative of the utility function to obtain an unambiguous spillover effect. Three different sufficient conditions are derived if the expected value of the exogenous risk is zero. The first condition is that risk aversion be standard—that is, that absolute risk aversion and absolute prudence be decreasing. The second condition is that absolute risk aversion be decreasing and convex. The third condition is that both the third and the fourth derivatives of the utility function be negative. If the expected value of the exogenous risk is positive, a wealth effect is added to the picture, which goes in the opposite direction if absolute risk aversion is decreasing.     

Bond yields and debt supply: new evidence through the lens of a preferred-habitat model

This paper examines the responsiveness of bond yields to changes in debt supply. The preferred-habitat theory predicts a positive relation between the term spread and relative supply of longer term debt, and that this relation is stronger when risk aversion is high. To capture this effect, a time-varying coefficient model is introduced and applied to German bond data. The results support the theoretical predictions and indicate substantial time variation: under high risk aversion, yield spreads react about three times more strongly than when risk aversion is low. The accumulated response of term spreads to a one standard deviation change in debt supply ranges between 4 and 46 basis points.     

Wealth, Information Acquisition, and Portfolio Choice

I solve (with an approximation) a Grossman-Stiglitz economyunder general preferences, thus allowing for wealth effects.Because information generates increasing returns, decreasingabsolute risk aversion, in conjunction with the availabilityof costly information, is sufficient to explain why wealthierhouseholds invest a larger fraction of their wealth in riskyassets. One no longer needs to resort to decreasing relativerisk aversion, an empirically questionable assumption. Furthermore,I show how to distinguish empirically between these two explanations.Finally, I find that the availability of costly informationexacerbates wealth inequalities.     

货币政策对居民就业影响实证分析

基于封闭经济下一般均衡分析框架,通过将内生劳动力供给引入Sidrauski模型,从货币供应量层面分析了货币政策对居民就业的影响。研究发现：如果消费者对商品消费的相对风险规避程度大于（小于）1,那么扩张性货币政策会促进（抑制）居民就业。考虑到目前中国居民消费的相对风险规避程度比较大,因而政府实施扩张性的货币政策有利于增加居民就业,实证检验也证实了这一结论。但从长期来看,居民消费的相对风险规避程度呈下降趋势,过度依赖于扩张性的货币政策来解决失业问题是不可行的。     

Does Inefficient Risk Sharing Increase Public Self-Protection?

This paper studies how the risk of having an unequal distribution of income across the population affects the investment in a public self-protection policy, such as financial regulation or climate change mitigation. Two economies are compared. In the first economy, there is perfect risk sharing, i.e., individuals can credibly commit on a set of transfers that will remove ex-post inequalities in consumption. In the second economy, no risk sharing takes place. By referring to the literature on background risks, I determine some conditions in terms of change in risk aversion and prudence, which guarantee an increase in self-protection under inefficient risk sharing. Generally speaking, if self-protection reduces the risk of inequality, the investment tends to rise when either the probability of a catastrophic event and/or the risk of inequality are sufficiently low. If self-protection increases the risk of inequality, the investment tends to rise when both the probabilities of aggregate loss and the increase in the risk of inequality are sufficiently small.     

Impact of Divergent Consumer Confidence on Option Prices

This paper investigates the impact of divergent consumer confidence on option prices. To model this, we assume that consumers disagree on the expected growth rate of aggregate consumption. With other conditions unchanged in the discrete-time Black–Scholes option-pricing model, we show that the representative consumer will have declining relative risk aversion instead of the assumed constant relative risk aversion. In this case all options will be underpriced by the Black–Scholes model under the assumption of bivariate lognormality. This revised version was published online in June 2006 with corrections to the Cover Date.     

Medical Labour Supply and the Production of Healthcare

Medical labour markets are important because of their size and the importance of medical labour in the production of healthcare and in subsequent patient outcomes. We present a summary of important trends in the UK medical labour market, and we review the latest research on factors that determine medical labour supply and the impact of labour on patient outcomes. The topics examined include: the responsiveness of labour supply to changes in wages, regulation and other incentives; factors that determine the wide variation in physician practice and style; and the effect of teams and management quality on patient outcomes. This literature reveals that while labour supply is relatively unresponsive to changes in wages, medical personnel do react strongly to other incentives, even in the short run. This is likely to have consequences for the quality of care provided to patients. We set out a series of unanswered questions in the UK setting, including: the importance of non‐financial incentives in recruiting and retaining medical staff; how individuals can be incentivised to work in particular specialties and regions; and how medical teams can be best organised to improve care.     

Lattices and Lotteries in Apportioning Risk

Although risk aversion has been used in economic models for over 275 years, the past few decades have shown how higher order risk attitudes are also quite important. A behavioural approach to defining such risk attitudes was developed by Eeckhoudt and Schlesinger, based on simple lottery preference. This article shows how the mathematics of lattice theory can be used to model these lottery preferences. In addition to modelling a simple lattice structure, I show how such lattices can be extended in order to develop a better understanding of higher order risk attitudes.     

CBDC uncertainty: Financial market implications

The current state of the art in the central bank digital currency (CBDC) literature views indexes constructed from digital currency news to be fully informed about CBDC uncertainty and its impact on the financial system. We argue that the hedging behavior of participants in the currency futures market could be more informative than CBDC uncertainty news in the presence of limited risk absorption capacity in futures markets. We show that the hedging factor has a statistically significant effect on financial market risk aversion and measures of uncertainty. The hedging behavior of currency futures market participants is informative of agents' reactions to the news and central bank policies around CBDC. Our results also show that CBDC uncertainty is a significant risk transmitter in the financial system. Hence, this characteristic makes the hedging factor even more important because it can directly impact risk aversion via its moderating effects, which later influence CBDC uncertainty.     

Risk-weighted capital requirements and portfolio rebalancing

We use a 2013 Norwegian policy reform to study how banks react to higher capital requirements and how these adjustments transmit to the real economy. Using bank balance sheet data, we document that banks raise capital ratios by reducing risk-weighted assets. Most of the reduction in risk-weighted assets is accounted for by a reduction in average risk weights. Consistent with this reduction in risk, we document a substantial decline in credit supply to the corporate sector relative to the household sector. We also show that banks react to higher requirements by increasing interest rates, consistent with the reduction in corporate credit growth being supply driven. Using administrative loan level tax data, we document a reduction in lending on the firm level. This is robust to controlling for firm fixed effects, thereby accounting for potential firm-bank matching. Finally, we find that the reduction in bank lending has a negative impact on firm employment growth and that this effect is driven by small firms.     

What is the impact of wealth shocks on asset allocation?

I test the assumption of constant relative risk aversion using U.S. macroeconomic data and analyse the role of wealth shocks in generating transitory changes in asset portfolio composition. I show that the risky asset share exhibits cyclical behavior and it is significantly (and positively) affected by unexpected variation in wealth. Therefore, the empirical evidence suggests that risk aversion is counter-cyclical. I also find that the portfolio share of housing wealth falls when the agent is faced with a positive wealth shock, i.e. housing is a hedge against unfavorable wealth fluctuations. Finally, considering a variety of wealth definitions, the results show that: (i) wealth effects are stronger for direct holdings of risky assets than for indirect holdings, which highlights that investors do not typically trade some assets such as pension or mutual funds; (ii) although significant, wealth effects on asset allocation are mainly temporary as agents quickly rebalance the asset portfolio composition (i.e. there is weak evidence of inertia or slow adjustment in asset allocation); and (iii) changes in expected returns partially explain the variation in risky asset allocation.     

Multivariate risk aversion and uninsurable risks: Theory and applications

The objective of this paper is to develop conditions for global multivariate comparative risk aversion in the presence of uninsurable, or background, risks, and thus generalize Kihlstrom and Mirman [1974] and Karni [1979,1989]. We analyze von Neumann-Morgenstern (VNM) utility functionsas well as smooth preference functionals which are nonlinear in distribution but locally linear in probabilities. In each case we provide an economic application which illustrates how our theorems can be used. We analyze a risk sharing, a portfolio choice, and a labor supply problem for VNM utility functions, and the optimal allocation of effort to risky technologies in the presence of a random supply (or quality) of a public good for nonlinear preference functionals. We consider thecase where the random variables are mean-independent as well as the case where they are independent. In the labor supply application for VNM utility functions, we show that if the two risks are independent, the comparative statics effect of greater risk aversion on labor supply in the presence of a background non-wage income risk is determined by a monotonic relationship between labor supply and the wage rate under certainty. That is, we extend the applicability of the Diamond-Stiglitz [1974]-Kihlstrom-Mirman [1974]single-crossing property to the case where an independent background risk is present.     

Stock market expectations and risk aversion of individual investors

We study the relationship between stock market return expectations and risk aversion of individuals and test whether the joint effects arising from the interaction of these two variables affect investment decisions. Using data from the Dutch National Bank Household Survey, we find that higher risk aversion is associated with lower stock market expectations. We identify significant and negative effects on the probability that individuals invest in stocks arising from the interaction between stock market expectations and risk aversion. These effects are in addition to a significant and positive impact from stock market return expectations as well as a significant and negative effect from risk aversion separately. However, once individuals participate in the stock market, their stock market expectations alone remain significant in determining their portfolio allocation decisions.