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.     

Valuation of vulnerable American options with correlated credit risk

This article evaluates vulnerable American options based on the two-point Geske and Johnson method. In accordance with the Martingale approach, we provide analytical pricing formulas for European and multi-exercisable options under risk-neutral measures. Employing Richardson’s extrapolation gets the values of vulnerable American options. To demonstrate the accuracy of our proposed method, we use numerical examples to compare the values of vulnerable American options from our proposed method with the benchmark values from the least-square Monte Carlo simulation method. We also perform sensitivity analyses for vulnerable American options and show how the prices of vulnerable American options vary with the correlation between the underlying assets and the option writer’s assets.      

当前我国植物油籽贸易的特征、发展趋势与对策

当前石油资源日趋枯竭,柴油供需缺口巨大,寻找和开发新的柴油替代能源势在必行。作为生物柴油开发的优质原料,大豆、油菜等植物油籽的国际工业化需求将会大幅上升,国内外油籽价格倒挂的现象将得到改善,我国植物油籽贸易也将出现新的局面。结合贸易自由化的背景,首先分析了目前我国植物油籽贸易的总量特征、产品结构特征及国别特征;其次分别对大豆、油菜籽、花生、芝麻、葵花籽等重点植物油籽产品的贸易特征及未来发展趋势做出了判断;最后针对当前我国植物油籽贸易中存在的问题,提出了相应的对策。     

The global economic consequences of the Uruguay Round

This paper examines the provisions of the recently completed Uruguay Round and evaluates the qualitative and quantitative effects of the Round on major countries and regions of the world. The implications of the Uruguay Round are measured using the G-cubed multicountry model. This model captures macroeconomic and sectoral linkages within the global economy. This study differs from other studies in that it considers the dynamic adjustment path, the impact of expectations formation, and the sectoral as well as macroeconomic consequences of the Round. The results are compared with other studies of the Uruguay Round. Ignoring major changes in productivity induced by the Round, it is found that the gains to the world economy are likely to be around $200 billion (1990) per year by the year 2000. The distribution of the gains across regions from the Round differ from other studies because of the adjustment of international capital flows. Private capital flows to regions that undertake the most extensive liberalization initially worsen their trade positions. In regions that liberalize less and experience a capital outflow, the production gains tends to be less than conventional studies find. The adjustment of private capital has important implications for exchange rates, and therefore for the adjustment of the international trading system over the decade of the implementation of the Round.     

贸易顺差与资产价格:内外经济失衡传导路径的一个检验

本文对一些学者提出的内外经济失衡的关系进行了考证。结果表明外部经济的失衡虽增强了货币供给的内生性,但并不必定导致内部资产价格的高涨。因此在政策选择上,要避免面对外部经济失衡采取一些应对内部经济失衡的政策工具来调节内部经济增长过快问题。同时,出于在经济发展过程中资产价格时间序列发生结构性变化的考虑,政策制定极有必要考虑资产价格因素。     

Fertility and the puzzle of female employment in the Middle East and North Africa

Female labour force participation rates across the Middle East and North Africa (MENA) region have remained low for over four decades even though, in the same period, women's education rapidly increased and fertility rates substantially decreased. This study provides a better understanding of this surprising phenomenon by testing whether the number of children affects the mother's labour supply (using twins at first birth as an instrumental variable.) Despite a strong first stage, it does not find statistically significant effects in the second stage, even in the combined sample of over 100,000 observations. This non‐result, however, does not rule out that fertility affects women's employment in these countries. But it rejects impacts larger than 0.09. Similar twin‐studies in the United States found effects between 0.12 and 0.31. The paper discusses the implications of this result in understanding the puzzle of female participation in MENA and in designing policies to increase women's employment.     

FDI对国际贸易的影响：来自中国的证据

本文利用2003~2006年的面板数据检验了我国外向与内向FDI存量与进出口贸易之间的关系。通过实证分析发现:我国的外向FDI与进出口均存在互补关系,因此外向FDI具有贸易创造效应,其中又以出口创造效应为甚,从而使我国的外向FDI具有"净出口"效应;而内向FDI与进出口的关系都不显著。     

Policy tolerance of economic crime? An empirical analysis of the effect of counterfeiting on Italian trade

Some governments seem ambivalent towards economic crime because, on the one hand, there are adverse effects on competition and legal businesses; on the other hand, there are benefits through (shadow) employment and income in less-developed areas, as well as benefits through relations of political clientage. We focus on counterfeiting and its economic effects on trade in Italy during the economic crisis. Using a newly built regional dataset and a dynamic panel model, we find evidence of the dual impact of counterfeiting. The production (and exchange) of fake goods depresses the legal market that relies on intellectual property rights but supports shadow-economic activities for the benefit of illegal workers, criminal organisations, and political clientele. We show that the negative effects outweigh the positive effects.     

On perpetual American put valuation and first-passage in a regime-switching model with jumps

In this paper we consider the problem of pricing a perpetual American put option in an exponential regime-switching Lévy model. For the case of the (dense) class of phase-type jumps and finitely many regimes we derive an explicit expression for the value function. The solution of the corresponding first-passage problem under a state-dependent level rests on a path transformation and a new matrix Wiener–Hopf factorization result for this class of processes. Research supported by the Nuffield Foundation, grant NAL/00761/G, and EPSRC grant EP/D039053/1.