Improved estimation of portfolio value‐at‐risk under copula models with mixed marginals

Portfolio value‐at‐risk (PVAR) is widely used in practice, but recent criticisms have focused on risks arising from biased PVAR estimates due to model specification errors and other problems. The PVAR estimation method proposed in this article combines generalized Pareto distribution tails with the empirical density function to model the marginal distributions for each asset in the portfolio, and a copula model is used to form a joint distribution from the fitted marginals. The copula–mixed distribution (CMX) approach converges in probability to the true marginal return distribution but is based on weaker assumptions that may be appropriate for the returns data found in practice. CMX is used to estimate the joint distribution of log returns for the Taiwan Stock Exchange (TSE) index and the associated futures contracts on SGX and TAIFEX. The PVAR estimates for various hedge portfolios are computed from the fitted CMX model, and backtesting diagnostics indicate that CMX outperforms the alternative PVAR estimators. © 2006 Wiley Periodicals, Inc. Jrl Fut Mark 26:997–1018, 2006     

Protection for sale with imperfect rent capturing

Abstract .  Grossman and Helpman (1994) explain tariffs as the outcome of a lobbying process. In most empirical implementations of this framework protection is instead measured using non-tariff barriers. Since tariffs allow the government to fully capture the rents from protection, while non-tariff barriers do not, the existing parameter estimates of the protection for sale model are likely to be biased. To address this problem, we augment the framework by considering instruments that allow partial capturing. Our specification is supported by the data, where we find that only 72–75% of the rent from protection is appropriated by the government.     

Permanent magnets: a technological analysis

Abstract
Technology analysis is a new technomanagerial discipline that provides common frameworks for analysing individual technologies and their relationships to each other. It is used here to probe the development of a particular technology, namely that of permanent magnets.
The paper traces the development of permanent magnets over the past decade and explores possible future improvements in performance parameters. The strength of magnets (i.e. energy product as expressed in kilo Joules per cubic metre) has increased from approximately 40 in the 1930s to approximately 400 at present.
Future developments will be constrained by a barrier which seems to exist at approximately 525 kilo Joules per cubic metre. However this is viewed as a barrier that can be transcended and not as an immutable limit. It therefore signifies a possible breakthrough zone.
S-curve theory leads analysts to speculate about a possible breakthrough during the five year period leading up to 1995. At that date magnetic strengths of 600+ kilo Joules per cubic metre could be aimed for.
Increased magnetic strength will improve the performance parameters of all technologies utilising magnets, unleash new magnetic based technologies and threaten many traditional areas in the fields of matter processing, transporting and storing, energy processing, and information processing and storing.
These effects will cascade through the entire technological landscape creating new markets and destroying others. The article gives an overview of these impacts on the technological landscape.     

Regulatory Monitoring and the Impact of Bank Holding Company Dividend Changes on Equity Returns

This paper examines the impact of announcements of dividend changes by bank holding companies (BHCs) on equity returns. Many empirical studies of dividend behavior reveal positive market responses to dividend increases, which have been interpreted as confirmation of the signalling theory of dividend behavior. These studies typically focus on “large” changes, however. We argue that BHCs allow for a stronger test of signalling theory because regulatory monitors, in effect, “certify” dividend signals. Consequently, even “small” dividend increases should result in positive abnormal equity returns. Using the event study methodology, our results generally confirm this hypothesis for a sample covering the period 1973–1987.     

PRINCIPAL AND AGENCY TRADES BY STOCKBROKERS ARE COMPLEMENTARY: THE WELFARE EFFECTS OF DEREGULATING AGENCY TRADING AND BANNING PRINCIPAL TRADES

This paper models the demand for stockbrokers' services in Australia, consisting of two related services, agency trades and principal trades. The relationship between agency and principal trades is estimated. The results indicate that the two services are complements rather than substitutes. Using unique accounting information, a model of agency and principal trading activities is estimated to determine the welfare effects of (i) deregulating brokerage commissions and (ii) a ban on principal trading by brokers. The results show a sizeable welfare gain to investors (amounting to about 60% of the gross revenue of brokers) stemming from deregulation of the minimum charge for agency trades. The loss in profitability by brokers due to deregulation is also computed and shown to be negligible. The results also show that due to complementarity, a ban on principal trading, even with deregulation of agency trading, can impose an arbitrarily high cost on investors which could, in principle, offset the gains from agency deregulation.     

Network neutrality and the nature of competition between network operators

The neutral architecture of the Internet is being challenged by various parties, such as network operators providing the connections to end-users, who are interested in gaining control of the information exchanged over the Internet. What are the effects on competition and welfare of such practices? Currently, there exists very little economic theory on network neutrality. This paper provides a preliminary analysis of the type of economic modeling that can address network neutrality, as well as of the type of results that can be expected.     

Intertemporal substitution and the liquidity effect in a sticky price model

The liquidity effect, defined as a decrease in nominal interest rates in response to a monetary expansion, is a major stylized fact of the business cycle. This paper first confirms that, with separable preferences, a low degree of intertemporal substitution in consumption is a necessary condition for the existence of the liquidity effect. In contrast to this result, in a model with non-separable preferences and capital accumulation it takes an implausibly high elasticity of intertemporal substitution to produce a liquidity effect. The robustness of these results to alternative degrees of nominal rigidities, capital adjustment costs and stochastic monetary processes is also analysed. We conclude that price stickiness, by itself, does not guarantee the existence of a liquidity effect.     

IntraLATA long-distance demand: carrier choice, usage demand and price elasticities

Competition in the long-distance market in the US continues to intensify; the 1996 Telecommunications Act has led to increased competition in long-distance telephony especially as the Regional Bell Operating Companies have begun to gain entry to long-haul, long-distance markets. In order to better understand the implications of having increased service offerings, models of how customers choose between carriers (and the impact of this choice on subsequent usage) will be useful. We develop the first publicly available models that simultaneously estimate choice and usage for intraLATA long-distance in the US. Utilizing a generalized Tobit model, the price responsiveness of usage and carrier choice are estimated. The results are generally consistent with expectations both in terms of theory and of practical experience in the industry.     

Technology Transfer and Learning

Despite the fact that international technology transfer has been widely studied its management still encounters many difficulties. To fully understand the issues that are relevant to the process of transferring production technology, it is necessary to determine the important factors that influence this process. Learning curves are often used as a means of determining the time required to become familiar with a transferred technology. The cases discussed in this paper have all employed learning curves, which were established at the outset of the transfer process and which turned out to be incorrect. As a consequence the envisaged efficiencies were not obtained. This phenomenon is partly due to the fact that when technology is transferred to a relatively inexperienced 'destination company', the curve is established based on the circumstances of the 'source company'. The case study findings lead to the conclusion that to establish a realistic curve a more comprehensive method is required than simply basing anticipated performance on that achieved at the source company.