A MULTINOMIAL APPROXIMATION FOR AMERICAN OPTION PRICES IN LÉVY PROCESS MODELS

This paper gives a tree-based method for pricing American options in models where the stock price follows a general exponential Lévy process. A multinomial model for approximating the stock price process, which can be viewed as generalizing the binomial model of Cox, Ross, and Rubinstein (1979) for geometric Brownian motion, is developed. Under mild conditions, it is proved that the stock price process and the prices of American-type options on the stock, calculated from the multinomial model, converge to the corresponding prices under the continuous time Lévy process model. Explicit illustrations are given for the variance gamma model and the normal inverse Gaussian process when the option is an American put, but the procedure is applicable to a much wider class of derivatives including some path-dependent options. Our approach overcomes some practical difficulties that have previously been encountered when the Lévy process has infinite activity.     

"Flexible" Work Practices and Occupational Safety and Health: Exploring the Relationship Between Cumulative Trauma Disorders and Workplace Transformation

This article matches establishment-level data on workplace transformation (e.g., quality circles, work teams, and just-in-time production) with measures of cumulative trauma disorders at these same establishments to explore the relationship between "flexible" workplace practices and workplace health and safety. The results reveal a positive, statistically significant, and quantitatively sizable relationship between cumulative trauma disorders and the use of quality circles and just-in-time production.     

The baby boom, the baby bust, and the housing market A second look

I re-examine Mankiw-Weil's (MW) claim that house prices will fall 47% by 2007. MW argue that the arrival of the Baby Boom generation at adulthood drove up prices during the 1970s. When the beginnings of the Baby Bust generation matured in the 1980s, prices softened. When this generation arrives in earnest, prices will collapse. I make three points: (1) The regression upon which MW hang their prediction has an implausible -8.1% trend, which drives their prediction. (2) Demand directly influences the rental price; the asset price (MW's variable) is influenced by demand only indirectly. I re-run MW's regression, replacing the asset price with the rental price, and their prediction disappears. (3) Relying on data presented by MW, I show that housing consumption rose during the 1970s, after adjusting for income growth. Just when MW say the asset price of housing was rising, consumers behaved as if the price were falling. Consumers were right: The rental price fell by approximately 20% during the 1970s.     

A comparison of several approximations to the power function of the likelihood ratio test in covariance structure analysis*

In this paper we compare alternative asymptotic approximations to the power of the likelihood ratio test used in covariance structure analysis for testing the fit of a model. Alternative expressions for the noncentrality parameter (ncp) lead to different approximations to the power function. It appears that for alternative covariance matrices close to the null hypothesis, the alternative ncp's lead to similar values, while for alternative covariance matrices far from H_o the different expressions for the ncp can conflict substantively. Monte Carlo evidence shows that the ncp proposed in Satorra and Saris (1985) gives the most accurate power approximations.     

Corporate Leverage and Nondebt Tax Shields: Evidence on Crowding-Out

A negative relationship between corporate leverage and tax shields has been predicted because a large nondebt tax shield reduces the expected value of interest tax savings and lessens the advantage of debt financing. Previous studies, however, have provided inconclusive and contradictory evidence on whether nondebt tax shields crowd-out debt financing. The analysis herein relies on unique constructs of discounted depreciation tax shields and presents evidence that crowding-out does not occur. Furthermore, it is shown that contradictory inferences may result from analysis of annual tax depreciation deductions instead of discounted tax shields. The findings suggest that firms with substantial cash flow from depreciation exploit their higher debt capacity by maintaining a capital structure with significantly more debt than otherwise.     

A longitudinal study of the cause and consequences of changes in diversification in the U.S. pharmaceutical industry 1977–1986

The paper hypothesizes that diversification by firms based in the pharmaceutical industry during the 1977-86 time period was primarily undertaken to reduce the risks associated with being dependent upon a technologically dynamic environment. Consistent with this non-efficiency motive for diversification, declining economic performance is predicted. A longitudinal empirical analysis provides support for these propositions.     

HOW TO CLEAR UP THE PENSIONS MESS

All three pillars of the British pensions system are crumbling. The basic state pension is unsustainable in its present form. Defined benefit occupational pension schemes are fast disappearing, and with them the retirement hopes of millions of workers. A further 3 million low-income earners are not saving enough for their retirement. And uncertainty about pensions choices is widespread. In each case the primary cause of the problem is governmental or regulatory failure. The paper makes eight general and four specific proposals for restoring the system.