Interpreting Value at Risk (VaR) forecasts

Value at Risk (VaR) forecasts have been increasingly accepted globally by both risk managers and regulators as a tool to identify and control exposure to financial market risk. However, modern portfolios are characterized by a constantly changing composition of security holdings that reflect portfolio managers’ strategies, expected prices, and net cash flows into the portfolio. As a result of these factors, portfolio returns are time-varying mixtures of distributions which are unlikely to be well approximated by conventional methods.     

中国的社会团体、公民社会和国家组合主义：有争议的领域

20世纪90年代中期以来学术界展开了一场争论：一派认为,应该用公民社会概念来研究中国团体;另一派通过调查研究认为,中国几乎所有团体的生活在本质上是国家组合主义。公民社会和组合主义都关注国家和社会之间的社团和其他机构。但不同的是：公民社会站在社会的角度,发展自治社团,维护“公共领域”的能力,以界定和制约国家权力;组合主义则相反,从国家的角度,为实现政府自己的目的,与选定的社团发展一种特殊的关系。在深入细致的实证研究基础上,学者们考察了中国不同类型社团的活动,得出了不同的结论,同时他们也超越了国家、社会和组合主义以及公民社会的框架,阐明了别的一系列重要的问题。     

Contestability in bus markets – evidence from the British de-regulated market

Following the 1985 Transport Act in Great Britain, reforms in the provision of bus services continue across Europe and other parts of the world to this day. The British experience, however, remains a key point of study in informing these continuing developments. This article looks at the issue of contestability in bus markets, and tests for the existence of the contestable market in Britain through an examination of fare levels, profit margins and technical efficiencies in 90 identifiable bus markets. The main conclusion is that there is evidence of the contestable market in Britain, however it can hardly be described as widespread, only found to be present in 15 of the 90 markets identified in the sample. The real issue however, particularly with regard to continuing reforms elsewhere in Europe, is the ability of regulatory authorities to maintain competitive and contestable (free) markets and the research suggests that in the face of market forces this is simply not possible. The only conclusion therefore is that contestability in the free market is not sustainable, and thus can only be introduced directly through franchising.     

Structural Economic Change and the Natural Environment in the Russian Federation

Many of Russia's contemporary environmental problems can be related, at least in part, to the activities of the Soviet period. However, the strength of this relationship can sometimes result in the environmental influences of post-Soviet society being ignored or understated. In recognition of this fact, this article examines the relationship between structural economic change and the natural environment in the post-Soviet period. The first part of the article is concerned with general economic trends and associated environmental consequences during the period 1990 to 1997. It then moves on to consider the environmental repercussions of structural changes within the country's industrial and agricultural sectors.     

The Information Content of Guidance and Earnings

I compare the information content of quarterly earnings guidance and quarterly earnings by examining their associations with current and future stock returns when the two signals are bundled at earnings announcements. At the bundled announcement, I find a significantly stronger association between announcement returns and guidance news. From the day after the bundled announcement through the next earnings announcement, both signals generate abnormal return drifts of about 200 basis points. However, the timing of the post-announcement returns differs considerably. For guidance, about 50% of the post-announcement drift occurs at the next earnings announcement. In contrast, for earnings, about 20% of the preceding drift reverses at the next earnings announcement. Investor ignorance of the drift following guidance news coupled with a fixation on post-earnings announcement drift potentially explains this surprising difference in the timing of the post-announcement returns. Overall, this study indicates that bundled quarterly earnings guidance contains more information than quarterly earnings and that investors incorrectly overweight the earnings news and underweight the guidance news during the post-announcement period until the next earnings announcement.     

Forecasting VoWLAN technology for the Taiwan mobile telecommunication industry

Disruptive innovation is always a great challenge to the management of incumbent firms, especially in fast-changing industries. In this study, scenarios were developed to facilitate strategic decision-making by incumbent mobile telecommunications firms that confront the threats of disruptive technology of voice over wireless local area network (VoWLAN). Combining various possible outcomes of uncertain conditions and strategic alternatives available to the incumbent firms, six scenarios were developed: incremental evolution, disruptive evolution, cost deterrence, fierce competition, market pre-emption and market convergence. The results show that a passive ‘do-nothing’ strategy by incumbent firms leads to failure if the disruptive technology is inevitable. However, firms can slow the pace of disruptive technology by applying a price-cut strategy and enjoy several years of profits in the process. Industrial insights and strategic implications obtained from all the scenarios are discussed.     

Mitigating shortage and distribution costs in damaged water networks

Recent events have sparked renewed interest in disaster mitigation for public infrastructures. Presidential Decision Directive 63 identifies water distribution as being among the most vital and vulnerable of our large-scale infrastructures. Water distribution networks are vulnerable to threats such as chemical and biological contamination, cyber attacks on computer-based management systems, and physical destruction from acts of nature and intentional attack. This research develops methods for configuring the undamaged portion of the water network to mitigate the consequences of physical destruction. The approach is to find a hydraulically feasible residual network that can be pressurized to meet the demand of a subset of demand sectors. Demand sectors not pressurized then receive water through truck distribution from pressurized sectors. The objective is to minimize weighted water shortage and water truck distribution costs by identifying sectors to pressurize along with an assignment of unpressurized sectors to pressurized sectors for water delivery by truck. The paper develops an optimization model, describes a solution method, and presents computational results for three example networks.     

Demand-side inertia factors and their benefits for innovativeness

Inertia reflects a firm’s inability to change or innovate and may be fostered by many sources. Though researchers have focused on internal inertia factors, we examine inertia factors within a firm’s customer base: switching costs, customer preference stability, and network externalities. New products at 279 firms are examined to assess the role of these demand-side inertia factors in determining innovativeness and, ultimately, financial performance. The inertia factors are hypothesized to have differential innovativeness effects for early and late entrants. Overall, demand-side factors affect innovativeness positively, contrasting with firm-based factors (e.g., routines or assets), which typically inhibit innovativeness. Consumer preference stability is the only factor negatively related to innovativeness, though only for early entrants. Network externalities and switching costs increase innovativeness (particularly for early entrants). Demand-side inertia factors are critical determinants of innovativeness and may now be placed within the previously internally focused set of factors engendering early mover advantage.