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     

对《形状和位置公差》新标准的理解和应用

通过对《形状和位置公差》新、旧国际的对比，综述了新、旧标准间的不同之处、便于迅速了解和应用新标准。     

Price rigidities and institutional variations in markets with posted prices

Summary Standard laboratory posted-offer markets respond slowly and incompletely to demand shocks. In these one-sided markets, where sellers control the setting of prices, very little information is transmitted via the process of exchange. For this reason, traders have trouble distinguishing randomness in their own experience from changes in market fundamentals. This paper reports the results of twelve laboratory markets conducted to assess whether some common variants to standard posted-offer rules can correct the adjustment deficiences. Although discounting, multiple postings and excess demand information all improve performance, we find that response remains poor, and efficiencies low.Support for this research was provided by the National Science Foundation (SBR 9319842 and SBR 9320044), and the University of Virginia Bankard Fund. Data are archived at FTP address: fido.econlab.arizona.edu. We wish to thank Charles Plott and Shyam Sunder for useful comments on an earlier draft of this paper. The usual disclaimer applies.     

德国如何成功举办世界杯足球赛

2006年德国世界杯足球赛是2008年北京奥运会之前全球最大的体育赛事。北京市发改委奥运经济高级顾问黄为专程前往德国，为北京奥运求取真经。[编者按]     

Remittances from international labour migration: a summary of findings and issues for labour-exporting developing countries of the ESCAP region

International labor migration from the ESCAP region to the Middle East is analyzed, and patterns of remittances from migrants are examined. The focus is on "contract" migration, in which the workers involved have no intention of settling in the country of employment and which is characterized by a job contract that is concluded by the employer on behalf of the workers. Topics discussed include the labor market situation, controversies over the benefits of remittances, the flow of migration and the stock of workers in host countries, characteristics of migrating workers, management of the migration flow, the size and significance of remittance flows to ESCAP countries, and policy issues.