Asymmetric Factor Substitutability and Indeterminacy

We consider a discrete-time two-sector CES economy with sector specific external effects in which factor substitutability differs across sectors. For this general model, we provide sufficient conditions on the elasticities of capital/labor substitution for local indeterminacy of equilibria.Acknowledgement We would like to thank two anonymous referees, the editor Dieter Bös and Tapan Mitra for comments on an earlier version of this paper, previously entitled Capital Depreciation, Factors Substitutability and Indeterminacy, which allowed us to improve considerably the results.     

Incentive Regulation and Telecommunications Service Quality

We examine the impact of incentive regulation—price regulation and earnings sharing regulation—on retail service quality in the U.S. telecommunications industry between 1991 and 2002. We find that incentive regulation is associated with significantly higher service quality on several dimensions (e.g., more rapid installation of new telephone service, fewer trouble reports, and increased customer satisfaction) but significantly lower quality on some dimensions (fewer installation commitments met and longer delays in resolving reported service problems)JEL Classification: L51, L96, L15We thank Michael Crew and two anonymous referees for helpful comments and suggestions. We are also grateful to Vanessa Cruz and Mircea Marcu for excellent research assistance.     

Environmental market creation: saviour or oversell?

In recent years considerable attention has been paid to the notion of market creation for the conservation of environmental assets. Market creation establishes a market in the external benefit or cost in question (e.g. biodiversity or pollution reduction) and leaves the relevant parties to adjust their behaviour accordingly. While most attention has been paid to market creation through tradable permits and taxes (the polluter-pays), it is less easy to secure a perspective on beneficiary-pays initiatives. Both polluter-pays and beneficiary-pays initiatives are examples of modified Coaseian bargains in which governments intervene in the bargains to lower transactions costs, establish property rights, deal with public goods issues, or act on behalf of disadvantaged groups. This paper reviews four major initiatives in this respect - debt-for-nature swaps, bioprospecting and the Global Environment Facility at the global level, and the Costa Rican Forest Law at the local level. It finds that while there is much to applaud in initiatives in these new markets, serious questions remain about the modest flows of funds associated with such global bargains, and the extent to which they secure environmental improvements relative to the baseline of business-as-usual.JEL Classification: D49, D62, H41, O19, Q57, Q2I am indebted to members of the Wildlife Conservation Research Unit at Oxford University and to David Simpson of Resources for the Future and University College London for valuable comments on an earlier version of this paper. Any remaining mistakes are entirely my responsibility.     

Optimal portfolios when stock prices follow an exponential Lévy process

We investigate some portfolio problems that consist of maximizing expected terminal wealth under the constraint of an upper bound for the risk, where we measure risk by the variance, but also by the Capital-at-Risk (CaR). The solution of the mean-variance problem has the same structure for any price process which follows an exponential Lévy process. The CaR involves a quantile of the corresponding wealth process of the portfolio. We derive a weak limit law for its approximation by a simpler Lévy process, often the sum of a drift term, a Brownian motion and a compound Poisson process. Certain relations between a Lévy process and its stochastic exponential are investigated.Received: January 2003Mathematics Subject Classification: Primary: 60F05, 60G51, 60H30, 91B28; secondary: 60E07, 91B70JEL Classification: C22, G11, D81We would like to thank Jan Kallsen and Ralf Korn for discussions and valuable remarks on a previous version of our paper. The second author would like to thank the participants of the Conference on Lévy Processes at Aarhus University in January 2002 for stimulating remarks. In particular, a discussion with Jan Rosinski on gamma processes has provided more insight into the approximation of the variance gamma model.     

Stochastic orders in dynamic reinsurance markets

We consider a dynamic reinsurance market, where the traded risk process is driven by a compound Poisson process and where claim amounts are unbounded. These markets are known to be incomplete, and there are typically infinitely many martingale measures. In this case, no-arbitrage pricing theory can typically only provide wide bounds on prices of reinsurance claims. Optimal martingale measures such as the minimal martingale measure and the minimal entropy martingale measure are determined, and some comparison results for prices under different martingale measures are provided. This leads to a simple stochastic ordering result for the optimal martingale measures. Moreover, these optimal martingale measures are compared with other martingale measures that have been suggested in the literature on dynamic reinsurance markets.Received: March 2004, Mathematics Subject Classification (2000): 62P05, 60J75, 60G44JEL Classification: G10     

An example of indifference prices under exponential preferences

The aim herein is to analyze utility-based prices and hedging strategies. The analysis is based on an explicitly solved example of a European claim written on a nontraded asset, in a model where risk preferences are exponential, and the traded and nontraded asset are diffusion processes with, respectively, lognormal and arbitrary dynamics. Our results show that a nonlinear pricing rule emerges with certainty equivalent characteristics, yielding the price as a nonlinear expectation of the derivatives payoff under the appropriate pricing measure. The latter is a martingale measure that minimizes its relative to the historical measure entropy.Received: July 2003, Mathematics Subject Classification: 93E20, 60G40, 60J75JEL Classification: C61, G11, G13The second author acknowledges partial support from NSF Grants DMS-0102909 and DMS-0091946. We have received valuable comments from the participants at the Conferences in Paris IX, Dauphine (2000), ICBI Barcelona (2001) and 14th Annual Conference of FORC Warwick (2001). While revising this work, we came across the paper by Henderson (2002) in which a special case of our model is investigated     

Nonregular designs from Hadamard matrices and their estimation capacity

Deng and Tang (1999) proposed the generalized minimum aberration (GMA) criterion to assess fractional factorial designs, and a design with GMA is often regarded as the best. However, there exist situations where some other designs may suit practical needs better. In this article, we propose an algorithm to sequentially examine designs obtained from Hadamard matrices under estimation capacity (EC) and provide designs with maximum or high EC for various combinations of run-size and number-of-factors. The usefulness of maximum or high EC designs is discussed.2000 Mathematics Subject Classification: 62K15, 05B20.Acknowledgements The research of Yingfu Li is supported by a Faculty Research Support Fund through the School of Science and Computer Engineering, University of Houston - Clear Lake. The authors are very grateful to the editor and two referees for their helpful comments that have led to the improvement of the paper.     

The large-sample joint distribution of key circular statistics

In this paper we derive the large-sample asymptotic joint distribution of the statistics used as fundamental measures of central location, concentration, skewness and kurtosis in the analysis of circular data. The importance of the distributional result in relation to inference for the corresponding population measures is illustrated, with various new confidence set constructions being derived and applied in the analysis of data from an animal orientation experiment.