Incentive contracts in delegated portfolio management under VaR constraint

This paper studies the incentive effect of linear performance-adjusted contracts in delegated portfolio management under a value-at-risk (VaR) constraint. It is shown that a linear performance-based contract can provide incentives for the portfolio manager to work at acquiring private information under a VaR risk constraint. The expected utility and optimal effort of a risk-averse manager are increasing functions of the return sharing ratio in the contract. However, a risk constraint causes the portfolio manager to reduce effort in gathering private information, suggesting that the VaR constraint increases the moral hazard between the investor and the manager.     

Share contracts and macroeconomic externalities

Weitzman's analysis of the share economy contrasts fixed-wage and fixed-share contracts; this paper notes that neither is an optimal labor contract, rendering the comparison suspect. Given this comparison, though, share contracts may be superior to wage contracts in an economy characterized by a “macroeconomic externality,” whereby firm-level employment decisions affect the demand for other firms' goods.     

Dynamic Incentive Contracts under No-Commitment to Periodic Auditing and a Non-retrospective Penalty System

This paper generalizes Khalil’s (1997) static model to a multiperiod one. The associated optimal dynamic contracts are derived and analyzed. At every-period’s equilibrium, the principal conducts no sure auditing. While duplication of the Baron-Myerson-type (1982) contract cannot be optimal, duplication of the Khalil-type (1997) contract can be optimal when the cheating penalty is large or discount factors are small. This implies that static contracts with no-commitment to auditing can describe players’ long-run behavior only under specific conditions. Moreover, our separating and pooling equilibria are compared with Baron and Besanko’s (1984a) and Laffont and Tirole’s (1987) equilibria, respectively.     

Are stocks desirable in tax-deferred accounts?

Existing literature suggests that, in order to maximize the tax benefit of retirement accounts, investors should follow a “pecking order” location rule of placing highly taxed assets (e.g., bonds) in a tax-deferred account and lightly taxed assets (e.g., stocks) in a taxable account. Empirical evidence, however, documents that a large number of investors violate this rule. In this paper, we show that such violations can be optimal for risk-averse investors who face portfolio constraints. In particular, while the strategy of placing bonds in the tax-deferred account maximizes the expected level of tax benefit, it may lead to volatile benefits under different realizations of stock returns. By holding a similar portfolio in both accounts, investors can achieve a more balanced growth in the two accounts, minimize the likelihood of violating the constraints in the future and hence “smooth” the volatility of the tax benefit. For some risk-averse investors, this smoothing motive can lead to the observed violation of the pecking order location rule. Our model predicts that such violations are more likely when future tax benefits are more volatile, which can occur, for example, when: (i) the tax rate differential across assets increases over time due either to tax law changes or to tax bracket changes for investors; (ii) asset returns are more volatile; and (iii) investors anticipate large future liquidity needs.     

报童投资组合模型中的批发价契约设计

当风险规避型报童的订货资金有限,却有多种产品可供订购时,供应商需要设计恰当的契约,以引导报童的订货行为,实现最大化自身收益的目的。针对上述问题,本文运用投资组合理论处理报童的决策问题;在此基础上建立了供应商与报童之间的博弈模型,设计了求解最优批发价契约的算法;通过数值算例,说明了最优契约的求解过程。结果表明,与未经优化而随机选择的契约相比,基于该算法求得的契约显著提升了供应商的期望收益。     

Double Moral Hazard,Monitoring, and the Nature of Contracts

generalized double-sided moral-hazard model, with risk-averse parties who mutually monitor each other (to get a reasonable idea of outcome/effort). The model considers trade-off between monitoring costs and moral hazard costs, which are endogenously determined by the extent of monitoring. Using this model, we formally prove a generalized version of Coase's conjecture – that the optimal contract minimizes the agency and risk costs. We then show how varying assumptions about the feasibility or cost of monitoring of the outcome or the worker's effort lead to different contracts being optimal. The analysis is then used to explain the nature of contracts observed in practice under many different situations. We will give an explanation as to why industrial workers typically work under wage contracts, while share contracts are common in agriculture and will explain why profit sharing is more common for senior managers than for the production workers. Received September 19, 2000; revised version received October 30, 1997     

Contracts and externalities: How things fall apart

A single principal interacts with several agents, offering them contracts. The crucial assumption of this paper is that the outside-option payoffs of the agents depend positively on how many uncontracted or “free” agents there are. We study how such a principal, unwelcome though he may be, approaches the problem of contract provision to agents when coordination failure among the latter group is explicitly ruled out. Two variants are considered. When the principal cannot re-approach agents, there is a unique equilibrium, in which contract provision is split up into two phases. In phase 1, simultaneous offers at good (though varying) terms are made to a number of agents. In phase 2, offers must be made sequentially, and their values are “discontinuously” lower: they are close to the very lowest of all the outside options. When the principal can repeatedly approach the same agent, there is a multiplicity of equilibria. In some of these, the agents have the power to force delay. They can hold off the principal's overtures temporarily, but they must succumb in finite time. In both models, despite being able to coordinate their actions, agents cannot resist an “invasion” by the principal and hold to their best payoff. It is in this sense that “things [eventually] fall apart”.     

Can the share economy cure our macroeconomic woes? Probably not

This paper introduces the major ideas in Martin Weitzman's The Share Economy. It notes that a “share” economy is one in which the marginal cost of labor is less than the average cost of labor; moreover, this condition can be induced by sharing revenues or profits. According to share theory, such contracts will lead firms to create more vacancies and thereby lower the average unemployment rate. Weitzman proposes to induce more share arrangements by giving a tax preference to share-type income.     

Imperfect common knowledge and the information value of prices

Summary. When economic agents have diverse private information on the fundamentals of the economy, prices may serve as a poor aggregator of this private information. We examine the information value of prices in a monopolistic competition setting that has become standard in the New Keynesian macroeconomics literature. We show that public information has a disproportionate effect on agents’ decisions, crowds out private information, and thereby has the potential to degrade the information value of prices. This effect is strongest in an economy with keen price competition. Monetary policy must rely on less informative signals of the underlying cost conditions.Received: 6 November 2003, Revised: 19 November 2004 JEL Classification Numbers: E31, E32, E58.This paper supersedes the discussion in the first half of our longer paper that circulated under the title “Public and Private Information in Monetary Policy Models”. We thank Andy Filardo, Marvin Goodfriend, Nobu Kiyotaki, John Moore, Stephen Morris and Lars Svensson for advice and comments at various stages of the project, and to Herakles Polemarchakis, Roko Aliprantis and an anonymous referee for their helpful comments and guidance. The views are those of the authors and do not necessarily represent those of the BIS. The second author acknowledges support from the U.K. ESRC under grant RES 000220450. Correspondence to: H.S. Shin     

Globally evolutionarily stable portfolio rules

The paper examines a dynamic model of a financial market with endogenous asset prices determined by short-run equilibrium of supply and demand. Assets pay dividends that are partially consumed and partially reinvested. The traders use fixed-mix investment strategies (portfolio rules), distributing their wealth between assets in fixed proportions. Our main goal is to identify globally evolutionarily stable strategies, allowing an investor to “survive,” i.e., to accumulate in the long run a positive share of market wealth, regardless of the initial state of the market. It is shown that there is a unique portfolio rule with this property—an analogue of the famous Kelly rule of “betting your beliefs.” A game theoretic interpretation of this result is given.     

Regulation of a Risk Averse Firm

We extend the Laffont–Tirole regulation model to the case of risk-averse firms. Our main results are:

• The impact of risk aversion is to shift the optimal contract toward a cost-plus contract.

• As compared with the risk-neutral case, distortions are greater and informational rents are smaller.

• For high levels of risk aversion, the optimal contract involves cost ceilings and the less efficient firms are bunched together.

Journal of Economic LiteratureClassification Numbers: D8, L5.     

Negative externalities and Sen’s liberalism theorem

Summary. Sen’s seminal, negative theorem about minimal liberalism has had a profound effect on economics, philosophy, and the social sciences. To address concerns raised by his result, we show how Sen’s assumptions must be modified to obtain positive conclusions; e.g., one resolution allows an agent to be decisive only if his choice does not impose “strong negative externalities” on others. We also uncover a significantly different interpretation of Sen’s societal cycles: rather than describing the rights of individuals to choose, the cycles identify when these choices impose difficulties on others. Other ways to address Sen’s difficulties come from game theory.Received: 14 October 2004, Revised: 7 March 2005, JEL Classification Numbers: D71, C70, D62.Donald G. Saari: Correspondenc toThe research of D. Saari was supported by NSF grant DMI-0233798. Our thanks to P. Hammond for suggesting some useful references. Some of our joint results were reported in Brunel (now Petron) (1998).     

The effects of information on strategic investment and welfare

Summary. The paper analyses the influence of uncertainty and competition on the strategic considerations of a firm’s investment decision, where the firm receives imperfect signals about the profitability of an investment project. We find a preemptive or an attrition equilibrium depending on a trade-off between first and second mover advantages. We show that welfare can be negatively affected by decreasing uncertainty, i.e. more and/or better information. Furthermore, simulations indicate that duopoly leads to higher welfare than monopoly if there are few and relatively non-informative signals, whereas the opposite holds if there are many and relatively informative signals.Received: 13 May 2004, Revised: 22 March 2005, JEL Classification Numbers: C61, D43, D81.Jacco J. J. Thijssen: Correspondence toDolf Talman is acknowledged for many inspiring discussions and meticulous proof-reading. Jan Boone, Thomas Sparla, participants in the workshop on “Recent Topics in Real Options Valuation”, July 2002, Krems, Austria, and an anonymous referee are thanked for helpful comments. The usual disclaimer applies.     

Optimal auctions with asymmetrically informed bidders

Summary. The paper analyzes a problem of optimal auction design when the seller faces asymmetrically informed bidders. Specifically, we consider a continuum of risk-neutral uninformed bidders taking part into the auction along with n risk-averse informed bidders. The contribution of the paper is threefold. First, we fully characterize the optimal auction in this non standard environment and in a very general set-up. We find that when informed bidders reveal “bad news” about the value of the good, the seller optimally awards the object to the uninformed bidders. Secondly, we show that the seller is better off in presence of uninformed bidders because this allows to lower the informational rents paid to the informed bidders. Last, we find that, with bi-lateral risk neutrality, the seller always awards the good to the uninformed bidders thereby keeping all the surplus.Received: 22 October 2004, Revised: 21 April 2005, JEL Classification Numbers: D44, D82.We are very grateful to two anonymous referees, Jacques Crémer, Patrick François, Angel Hernando-Veciana and seminar participants at the 2004 SCSE conference (Quebec, Canada) for their valuable comments. Moez Bennouri acknowledges the financial support by the Initiative of the New Economy (INE) program of SSHRC (Canada).     

Incentive Contract and Weather Risk

We study contracts designed to remunerate a farmer for the production of an ecosystem service with the payment dependent on the results of the farmer’s actions and on weather conditions. Two contracts are proposed: the first takes into account both the results of the farmer’s actions and a weather variable that reflects the actual atmospheric conditions during the life of the contract; the second bases the payment on the results alone incorporating only the average effect of weather. Social welfare is optimal when both the results and the specific atmospheric conditions are taken into account; however, this type of contract may be less acceptable to the farmer due to his perception of the level of risk involved.We thank two referees for valuable comments.     

Bundling, product choice, and efficiency: Should cable television networks be offered à la carte?

We conduct a numerical analysis of bundling’s impact on a monopolist’s pricing and product choices and assess the implications for consumer welfare in cable television markets. Existing theory is ambiguous: for a given set of products, bundling likely transfers surplus from consumers to firms but also encourages products to be offered that might not be under à la carte pricing. Simulation of “Full À La Carte” for an economic environment calibrated to an average cable television system suggests that consumers would likely benefit from à la carte sales. If all networks continued to be offered, the average household’s surplus is predicted to increase by $6.80 (65.6%) under à la carte sales (despite a total bundle price that almost doubles) and reduced network profits would have to be such that 41 of 50 offered cable networks have to exit the market to make her indifferent. Simulation of a “Theme Tier” scenario provides intermediate benefits. The incremental marginal costs to cable systems of à la carte sales and its impact in the advertising market and on competition are important factors in determining consumer benefits.     

Optimal employment contracts with bankruptcy constraints

Consider the optimal incentive compatible contract offered by a firm with private information to its risk-averse employees. If the firm is subject to a binding limited liability or bankruptcy constraint then the contract will yield underemployment in low productivity states (relative to full-information efficiency). Such contracts either yield underemployment in all states, or excessively high variability in employment.     

Under what conditions may social contracts arise? Evidence from the Hanseatic League

Social contractarians commonly take social contracts to be solely hypothetical and refrain from elaborating on the factors that influence the feasibility of the formation of social contracts. In contrast, this paper aims at providing a discussion of the conditions affecting the feasibility of social contracts. I argue that the more aligned the preferences of group members for public goods are, the more the individuals share similar social norms, and the smaller the group is the more feasible a genuine social contract becomes. I provide evidence in support of my contention from the medieval Hanseatic League. At the Hanseatic Kontor in Novgorod, one of the four major trading posts of the Hanseatic League in cities outside of Germany, German merchants agreed to live under the rule of a constitution that gave rise to a political authority for the Kontor society.     

Comment on “A note on the Hotelling principle of minimum differentiation: Imitation and crowd”

We argue that the minimum differentiation firm location equilibrium and the pure strategy pricing equilibrium in Di Cintio’s [Di Cintio, M., 2007. A note on the Hotelling principle of minimum differentiation: Imitation and crowd. Research in Economics 61 (3), 122–129] “Note” need not exist under the conditions claimed.