On the multiplicity of option prices under CEV with positive elasticity of variance

The discounted stock price under the Constant Elasticity of Variance model is not a martingale when the elasticity of variance is positive. Two expressions for the European call price then arise, namely the price for which put-call parity holds and the price that represents the lowest cost of replicating the call option’s payoffs. The greeks of European put and call prices are derived and it is shown that the greeks of the risk-neutral call can substantially differ from standard results. For instance, the relation between the call price and variance may become non-monotonic. Such unfamiliar behavior then might yield option-based tests for the potential presence of a bubble in the underlying stock price.     

Business Cycles Around the Globe: Some Key Facts

We document massive heterogeneity in basic cyclical patterns within groups of developed and emerging market economies. While we detect marked differences between developed and emerging countries as well, the distributions of key business cycle statistics tend to overlap across different country groups.     

More pessimism than greediness: a characterization of monotone risk aversion in the rank-dependent expected utility model

Summary. This paper studies monotone risk aversion, the aversion to monotone, mean-preserving increase in risk (Quiggin [21]), in the Rank Dependent Expected Utility (RDEU) model. This model replaces expected utility by another functional, characterized by two functions, a utility function u in conjunction with a probability-perception function f. Monotone mean-preserving increases in risk are closely related to the notion of comparative dispersion introduced by Bickel and Lehmann [3,4] in Non-parametric Statistics. We present a characterization of the pairs (u,f) of monotone risk averse decision makers, based on an index of greediness G _u of the utility function u and an index of pessimism P _f of the probability perception function f: the decision maker is monotone risk averse if and only if . The index of greediness (non-concavity) of u is the supremum of taken over . The index of pessimism of f is the infimum of taken over 0 < v < 1. Thus, , with G _u = 1 iff u is concave. If then , i.e., f is majorized by the identity function. Since P _f = 1 for Expected Utility maximizers, forces u to be concave in this case; thus, the characterization of risk aversion as is a direct generalization from EU to RDEU. A novel element is that concavity of u is not necessary. In fact, u must be concave only if P _f = 1.Received: 10 April 2001, Revised: 18 November 2003, JEL Classification Numbers: D81. Correspondence to: Michéle CohenAlain Chateauneuf, Michéle Cohen, Isaac Meilijson: We are most grateful to Mark Machina, Peter Wakker and two anonymous referees for very helpful suggestions and comments.     

On the existence of a regulated production function

This paper examines the generalization of the regulated production function. It characterizes the set of admissible regulatory constraints that are compatible with the existence of a regulated production function in a sufficiently weak framework to encompass the usual rate-of-return constraints à la Averch and Johnson and value constraints.     

Providing global public goods under uncertainty

We study how uncertainty and risk aversion affect international agreements to supply global public goods. We consider a benchmark model with homogeneous countries and linear payoffs. When countries directly contribute to a public good, uncertainty tends to lower signatories' efforts but may increase participation. Despite risk aversion, uncertainty may improve welfare. In contrast, when countries try to reduce a global public bad, uncertainty tends to increase signatories' efforts and decrease participation. In that case, an ex-ante reduction of uncertainty may have a large positive multiplier effect on welfare.     

Commonalities in the order book

This paper uses data from one of the most important European stock markets and shows that, in line with predictions from theoretical market microstructure, a small number of latent factors captures most of the variation in stock specific order books. We show that these order book commonalities are much stronger than liquidity commonality across stocks. The result that bid and ask side as well as the visible and hidden parts of the order book exhibit quite specific dynamics is interpreted as evidence that open order book markets attract a heterogeneous trader population in terms of asset valuations and impatience. Quantifying the informational content of the extracted factors with respect to the evolution of the asset price, we find that the factor information shares are highest (about 10%) for less frequently traded stocks. We also show that the informational content of hidden orders is limited.

Pacifying monogamy

This paper proposes a theory of institutionally imposed monogamy. In a society where many women are allocated to the elite, there are high returns for the non-elite men to rebel. Monogamy, or “constrained” polygyny, can pacify non-elite men, and thus serve the elite’s reproductive interests. The more unequal is the society, the stricter constraints the elite want to impose on themselves. This suggests how monogamy might have arisen in response to rising class cleavages, e.g., in the wake of the introduction of agriculture. Another result is that, if the elite can write a law that commits not only themselves but also any group that would come to replace them in a rebellion, then polygyny will be more constrained than if they cannot. We speculate that the Church in Europe may have facilitated the imposition of such binding constraints.