Borrowing constraints,the cost of precautionary saving and unemployment insurance

When it is costly for individuals to save or to borrow, unemployment insurance (UI) provides an alternative source of liquidity that smooths consumption over time and leads individuals to spend longer unemployed searching for a suitable job. We show in a tractable life-cycle model how the optimal unemployment replacement ratio and the fall in consumption on job loss depend on the cost of self-insurance and the cost of borrowing. This implies that the value of UI depends on age at job loss, consumption needs (such as the presence of children), discount rates, the return on saving, access to credit and the presence of other social insurance programmes. Optimal replacement rates vary substantially with plausible variation in these factors (from less than 20 percent to almost 60 percent).     

From precautionary inadequacy to participatory risk management

This paper examines the case of mobile telephone infrastructure as an example of a contemporary risk defined by a lack of scientific evidence and consensus as regards potential or future harm. This uncertainty has led to recourse to the precautionary principle at the European, national, regional and local level of EMF risk management. Local risk governance of mobile telephone infrastructures in Catalonia can be seen as an example of a socio-technical complex system linked to risk perception which highlights the limitations of the precautionary principle in a scientifically uncertain context. Active participation of stakeholders and the public in risk management arenas is required if current technocratic risk management strategies are to be superseded by transparent processes of decision-making in risk management spheres.     

Pricing innovations in consumption growth: A re-evaluation of the recursive utility model

We re-evaluate the cross-sectional asset pricing implications of the recursive utility function of  and , using innovations in future consumption growth in our tests. Our empirical specification helps explain the size, value and momentum effects. Specifically, we find that (?) the beta associated with news about consumption growth has a systematic pattern: beta decreases along the size dimension and increases along the book-to-market and momentum dimensions, (??) innovation in consumption growth is significantly priced in asset returns using both the Fama and MacBeth (1973) and the stochastic discount factor approaches, and (???) the model performs better than both the CAPM and Fama–French model.     

Pricing jump risk with utility indifference

This paper is concerned with option pricing in an incomplete market driven by a jump-diffusion process. We price options according to the principle of utility indifference. Our main contribution is an efficient multi-nomial tree method for computing the utility indifference prices for both European and American options. Moreover, we conduct an extensive numerical study to examine how the indifference prices vary in response to changes in the major model parameters. It is shown that the model reproduces ‘crash-o-phobia’ and other features of market prices of options. In addition, we find that the volatility smile generated by the model corresponds to a zero mean jump size, while the volatility skew corresponds to a negative mean jump size.     

Convertibility risk: the precautionary demand for foreign currency in a crisis

This paper presents theoretical work linking money demand to the perceptions of households about the risk that domestic currency may become inconvertible or that it may be devalued. An empirical investigation of the size of this effect is carried out using monthly data for Korea to estimate an augmented demand-for-money equation. It is found that the fear of inconvertibility arising from the 1997 Korean currency crisis may have caused broad money demand to fall by 4–5% points,equivalent to the loss of reserves of $6–7.5 billion (or about 30% of reserves as measured at end-November 1997). This is a revised version of IMF Working paper WP/2001/210; it was written while Professor Black was Senior Policy Advisor at the IMF Institute and Christofides and Mourmouras were staff members in the IMF’s Policy Development and Review Department. The views expressed are those of the authors and should not be attributed to the IMF, its Executive Board, or its management. For useful comments and suggestions we thank an anonymous referee, Tim Lane, Ydahlia Metzgen, Roberto Perelli, Tony Richards, Christian Mulder, Steve Russell, as well as seminar participants at the IMF Institute, the IMF’s Asia and Pacific Department, Federal Reserve Board, and Bank of Indonesia. We would also like to note similar (unpublished) empirical results using our approach by Dr. Rino Effendi for Indonesia and Angana Banerji for Russia     

Exponential utility maximization under partial information

We consider the exponential utility maximization problem under partial information. The underlying asset price process follows a continuous semimartingale and strategies have to be constructed when only part of the information in the market is available. We show that this problem is equivalent to a new exponential optimization problem which is formulated in terms of observable processes. We prove that the value process of the reduced problem is the unique solution of a backward stochastic differential equation (BSDE) which characterizes the optimal strategy. We examine two particular cases of diffusion market models for which an explicit solution has been provided. Finally, we study the issue of sufficiency of partial information.     

CVP under uncertainty and the manager's utility function

Cost-volume-profit analysis has focused on the firm's short-run output decision assuming that the manager maximizes the firm's objective function rather than his or her own. This study argues that the decision problem facing the manager is to determine not only the level of output, but also the level of investment in risky assets in such a way that the expected utility of the manager's own end-of-period wealth can be maximized when the manager's wealth function is dependent on vested interests both within and outside of the firm, possibly in competition with the firm. Through analytical work, it is demonstrated that a change in fixed costs of the firm affects not only the production decision of a manager, but also his orher decision to invest in risky assets. The direction of this fixed cost effect depends on the particular type of risk aversion displayed by the manager. From the analytical work, five propositions are developed for empirical investigation in the future.The most helpful comments of Professor Cheng-few Lee are greatly acknowledged. We wish to thank anonymous referees who's comments have improved the paper. Furthermore, participants at the seminar at the University of Massachusetts Lowell also provided helpful comments.     

Rollover risk and credit risk under time-varying margin

For a firm financed by a mixture of collateralized (short-term) debt and uncollateralized (long-term) debt, we show that fluctuations in margin requirements, reflecting funding liquidity shocks, lead to increasing the firm’s default risk and credit spreads. The severity with which a firm is hit by increasing margin requirements highly depends on both its financing structure and debt maturity structure. Our results imply that an additional premium should be added when evaluating debt in order to account for rollover risks, especially for short-matured bonds. In terms of policy implications, our results strongly indicate that regulators should intervene fast to curtail margins in crisis periods and maintain a reasonably low margin level in order to effectively prevent creditors’ run on debt.     

A note on wealth effect under CARA utility

There is a simple but overlooked way of capturing the wealth effect under CARA utility via making the absolute-risk aversion parameter wealth-dependent. We implement this approach in the asymmetric information setting of Verrecchia (1982), and compare it with the alternative approach of changing the utility function (Peress, 2004). Ours is a straightforward tractable extension of Verrecchia, while Peress has to resort to approximate methods. Importantly, our closed-form solution reveals that the relation between wealth and wealth share invested in a risky asset can be negative, while Peress’s main result is that this relation is uniquely positive.     

Genetically modified plants and the precautionary principle

The European regulation of genetically modified plants is a particular example of technological risk management that has become an essential part of the management of change. The role of regulators in this management process, when there are demands for regulatory action concerning unquantified (and sometimes unquantifiable) technological risks – with regulation under conditions of uncertainty – is explored. Where the retrospective evidence concerning a postulated risk scenario is sparse, the precautionary principle (PP) may be invoked. The origins of the European regulatory system, which applied until 17 October 2002 (Directive 90/220), why this has been revised (Directive 2001/18) and the probable impact of this revision are described. This is illustrated with risk assessments that have accompanied submissions for marketing approval for genetically modified plants under Directive 90/220. Some of the problems associated with the PP and the regulation of GM plants are discussed.     

Europe's precautionary principle: promise and pitfalls

The European Union, through a recent 'Communication' from the Commission, has sought to legitimize the precautionary principle while establishing criteria for adoption of appropriate precautionary measures. Although the precautionary principle is not new and indeed reflects a basic human instinct, this article argues that the EC makes a constructive contribution towards formalizing it by describing the principle in the context of established processes of risk analysis: objective scientific evaluation, risk assessment, risk management and risk communication. The EC's reference to a broad spectrum of precautionary measures, subject to specific managerial criteria, also offers some assurance that the principle shall be implemented through thoughtful processes of decision making. There are pitfalls in the EC approach that should be rectified in future refinements of the principle. Critical terms need to be defined, the evidentiary hurdles for precaution need to be clarified, and checks and balances against ill-considered application of the principle need to be strengthened. A systematic process of ranking hazards and targeting cost-effective protection opportunities should be implemented by the EC as a counterweight to enactment of precautionary measures on a crisis-by-crisis basis.     

Optimal insurance contract and coverage levels under loss aversion utility preference

This study develops an optimal insurance contract endogenously and determines the optimal coverage levels with respect to deductible insurance, upper-limit insurance, and proportional coinsurance, and, by assuming that the insured has an S-shaped loss aversion utility, the insured would retain the enormous losses entirely. The representative optimal insurance form is the truncated deductible insurance, where the insured retains all losses once losses exceed a critical level and adopts a particular deductible otherwise. Additionally, the effects of the optimal coverage levels are also examined with respect to benchmark wealth and loss aversion coefficient. Moreover, the efficiencies among various insurances are compared via numerical analysis by assuming that the loss obeys a uniform or log-normal distribution. In addition to optimal insurance, deductible insurance is the most efficient if the benchmark wealth is small and upper-limit insurance if large. In the case of a uniform distribution that has an upper bound, deductible insurance and optimal insurance coincide if benchmark wealth is small. Conversely, deductible insurance is never optimal for an unbounded loss such as a log-normal distribution.     

Saving under uncertainty: A bivariate non-expected utility approach

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.     

Buffer stocks and precautionary savings with loss aversion

This paper reexamines buffer stocks and precautionary savings in the presence of loss aversion. We assume that agents are disappointment averse, as in Gul [Econometrica, 59 (1991) 667–686]. We show that the concavity of the marginal utility continues to determine precautionary saving, but its effect is of a second order magnitude (proportional to the square of the coefficient of variation) compared to the first order effect (proportional to the coefficient of variation) induced by loss aversion. We show that a stabilization fund that is rather small when agents are maximizing the conventional expected utility, turns out to be rather large with loss aversion.     

Portfolio optimization under a generalized hyperbolic skewed t distribution and exponential utility

In this paper, we show that if asset returns follow a generalized hyperbolic skewed t distribution, the investor has an exponential utility function and a riskless asset is available, the optimal portfolio weights can be found either in closed form or using a successive approximation scheme. We also derive lower bounds for the certainty equivalent return generated by the optimal portfolios. Finally, we present a study of the performance of mean–variance analysis and Taylor’s series expected utility expansion (up to the fourth moment) to compute optimal portfolios in this framework.     

Time-consistent reinsurance and investment strategies for an AAI under smooth ambiguity utility

This paper investigates time-consistent reinsurance(excess-of-loss, proportional) and investment strategies for an ambiguity averse insurer(abbr. AAI). The AAI is ambiguous towards the insurance and financial markets. In the AAI's attitude, the intensity of the insurance claims' number and the market price of risk of a stock can not be estimated accurately. This formulation of ambiguity is similar to the uncertainty of different equivalent probability measures. The AAI can purchase excess-of-loss or proportional reinsurance to hedge the insurance risk and invest in a financial market with cash and an ambiguous stock. We investigate the optimization goal under smooth ambiguity given in Klibanoff, P., Marinacci, M., & Mukerji, S. [(2005). A smooth model of decision making under ambiguity. Econometrica 73, 1849–1892], which aims to search the optimal strategies under average case. The utility function does not satisfy the Bellman's principle and we employ the extended HJB equation proposed in Björk, T. & Murgoci, A. [(2014). A theory of Markovian time-inconsistent stochastic control in discrete time. Finance and Stochastics 18(3), 545–592] to solve this problem. In the end of this paper, we derive the equilibrium reinsurance and investment strategies under smooth ambiguity and present the sensitivity analysis to show the AAI's economic behaviors.