OPTIONS AND EFFICIENCY IN MULTIDATE SECURITY MARKETS

This paper extends the work of Ross (1976; Q. J. Econ. (90)1, 75–89) to multidate security markets. First, we show that if a primitive security separates states at the terminal date, then there exist multiperiod European options on that security generating dynamically complete markets. Second, we show that if a primitive security conditionally separates states at the terminal date, then there exist multiperiod European options on that security generating generically dynamically complete markets provided that certain conditions hold. Third, we show that there are economies for which the minimum number of multiperiod European options on a primitive security generating generically dynamically complete markets is relatively large. Finally, we show that in these economies, a relatively small number of multiperiod European options on possibly different portfolio strategies of primitive securities generates generically dynamically complete markets.     

Stochastic Models of Implied Volatility Surfaces

We propose a market–based approach to the modelling of implied volatility, in which the implied volatility surface is directly used as the state variable to describe the joint evolution of market prices of options and their underlying asset. We model the evolution of an implied volatility surface by representing it as a randomly fluctuating surface driven by a finite number of orthogonal random factors. Our approach is based on a Karhunen–Loeve decomposition of the daily variations of implied volatilities obtained from market data on SP500 and DAX options.
We illustrate how this approach extends and improves the accuracy of the well–known 'sticky moneyness' rule used by option traders for updating implied volatilities. Our approach gives a justification for the use of 'Vegas' for measuring volatility risk and provides a decomposition of volatility risk as a sum of independent contributions from empirically identifiable factors.
(J.E.L.: G130, C14, C31).     

Small dimension PDE for discrete Asian options

This paper presents an efficient method for pricing discrete Asian options in presence of smile and non-proportional dividends. Using an homogeneity property, we show how to reduce an n0 dimensional problem to a one- or two-dimensional one. We examine different numerical specifications of our dimension reduced PDE using a Crank–Nicholson method (interpolation method, grid boundaries, time and space steps) as well as the extension to the case of non-proportional discrete dividends, using a jump condition. We benchmark our results with Quasi Monte-Carlo simulation and a multi-dimensional PDE     

Modeling Distribution Services and Assessing Their Welfare Effects in a General Equilibrium Framework

Most international trade models fail to account for the fact that almost all goods must pass through the distribution sector. The authors compare different approaches to modeling distribution within an Applied General Equilibrium framework and find that such modeling may significantly affect trade opening simulations. They also predict large potential gains from streamlining distribution. For instance, a 10% reduction in Japan's final goods distribution margins would benefit it as much as worldwide free trade would. They also find that, compared to trade opening, reducing margins leads to smaller inter‐sectoral production shifts and thus may engender less political opposition.     

Towards a Theory of Organizational Improvisation: Looking Beyond the Jazz Metaphor

abstract This paper calls for research on organizational improvisation to go beyond the currently dominant jazz metaphor in theory development. We recognize the important contribution that jazz improvisation has made and will no doubt continue to make in understanding the nature and complexity of organizational improvisation. This article therefore presents some key lessons from the jazz metaphor and then proceeds to identify the possible dangers of building scientific inquiry upon a single metaphor. We then present three alternative models – Indian music, music therapy and role theory. We explore their nature and seek to identify ways in which the insights they generate complement those from jazz. This leads us to a better understanding of the challenges of building a theory of organizational improvisation.     

On the Non-Existence of Redundant Options

In a seminal paper, Ross (Q J Econ 90:75–89, 1976) shows that if security markets are resolving, then there exist (non-redundant) options that generate complete security markets. Complementing his work, Aliprantis and Tourky (2002) show that if security markets are strongly resolving and the number of primitive securities is less than half the number of states, then every option is non-redundant. Our paper extends Aliprantis and Tourky’s result to the case when their condition on the number of primitive securities is not imposed. Specifically, we show that if there exists no binary payoff vector in the asset span, then for each portfolio there exists a set of exercise prices of full measure such that any option on the portfolio with an exercise price in this set is non-redundant. Since the condition that there exists no binary payoff vector in the asset span holds generically, redundant options are thus rare. I am grateful to an anonymous referee for very helpful comments. Research support from the School of Business at The George Washington University is gratefully acknowledged     

Externalities,Cross-Sectoral Spillovers and Productivity Growth

We provide an interpretation of the productivity dynamics in the manufacturing sector based on the idea of the thick market externality à la Diamond. An econometric model has been estimated which allows to disentangle the long run effects of these trading externalities from those of internal economies of scale and of aggregate industry-level economies. The results obtained—based on a cointegrated system of non-linear-error-correction equations—confirm the hypothesis that the trading externality matters. Moreover, our findings point out that the emphasis generally posited both on internal and external economies of scale is not justified.     

Does the Basle Capital Accord reduce bank fragility? An assessment of the value-at-risk approach

We examine the economic implications arising from a bank using a VaR-constrained mean-variance model for the selection of its trading portfolio as a consequence of the Basle Capital Accord. Surprisingly, we show that when a VaR constraint is imposed, it is plausible that certain banks will end up selecting ‘riskier’ portfolios than they would have chosen in the absence of the constraint. Accordingly, regulators such as the Basle Committee on Banking Supervision should be aware that allowing a bank to use VaR to determine its minimum regulatory capital may increase its fragility. Alternatives to VaR-based bank capital regulation that mitigate or even preclude its perverse implications are presented.     

Is globalization a road to duopoly?

In global markets, the market shares of the two or three biggest firms sum up more than 90 percent and firms do marketing efforts. However, the classical neo-walrasiano theoretical framework only is able to justify these stylized facts with particular firms’ cost structures, being one reason the presumption that there are no information costs. Towards the rationalization of those stylized facts, I study the evolution of the market structure in a model of price advertising with a variable that controls the degree of openness of regional markets. The main result of the model is that in equilibrium the structure of a global market is the duopoly.