“智慧的地球”是怎么回事？

＂智慧的地球＂并不只是围绕着一种概念,是真正一系列我们可以采取行动的技巧,能够应用在面对的所有挑战当中。     

Dynamic Correlations Among Asset Classes: REIT and Stock Returns

We use the Dynamic Conditional Correlation model with Generalized Autoregressive Conditional Heteroskedasticity (DCC-GARCH) developed by Engle (Journal of Business & Economic Statistics 20(3):339–350, 2002) to examine dynamics in the correlation of returns between publicly traded REITs and non-REIT stocks. The results suggest that REIT-stock correlations form three distinct periods. During the first period, ending in August 1991 with the start of the modern REIT era, correlations were high and without trend, never dipping below 59%. During the second period, ending in September 2001 with the inclusion of REITs in broad stock market indexes, correlations declined precipitously to 30%, enabling substantially higher portfolio allocations to both high-return asset classes and therefore higher portfolio returns without increasing portfolio volatility. During the third period, since September 2001, correlations increased steadily but only reached 59% in late 2008. A simple portfolio optimization suggests that asset managers would be willing to pay 20 basis points per year, plus the difference in transaction costs, for the ability to use DCC-GARCH modeling of dynamic correlations in place of rolling 24-month asset correlations.     

Measuring the Euro area output gap using a multivariate unobserved components model containing phase shifts

Several recent studies have used multivariate unobserved components models to identify the output gap and the non-accelerating inflation rate of unemployment. A key assumption of these models is that one common cycle component, such as the output gap, drives the cyclical fluctuations in all variables included in the model. This article also uses the multivariate approach to estimate the euro area output gap and the trends and cycles in other macroeconomic variables. However, it adopts a flexible way of linking the output gap to the cycle components in the other variables, in that we do not impose any leading or lagging restrictions between cycle components, as has been done in most previous studies. Our approach also allows us to assess the strength of cycle association and cross-correlation among cycle components using the model??s parameter estimates. Finally, we demonstrate that our multivariate model can provide a satisfactory historical output gap estimate and also a ??real-time?? estimate for the aggregate euro area.     

Employment-Based Health Insurance and the Effectiveness of Intrafirm Competition between Insurance Providers

This paper examines the effects of competition between insurers for the patronage of a firm's employees. Since for employment-based health insurance the employee choice of health insurance plans is often limited, the availability of competing plans in the market does not necessarily reflect competition within the firm. We utilize data from the 1987 National Medical Expenditures Survey (NMES) to examine the effect of intra firm competition in the employment-based health insurance market. Using switching regression models, we explore the process that sets premiums and the process that sets the net premium/medical cost margins. We find that greater choice results in higher margins and lower premiums. We also find significantly negative health maintenance organization choice effects on both premiums and margins.     

Quasi-Partnerships in Distribution

This paper concerns the sale of a vertically differentiated good by a manufacturer to retailers that have market power when reselling to consumers. The contractual relationships between the manufacturer and individual retailers are characterized as “quasi-partnerships,” reflecting the ongoing and multi-dimensional nature of such relationships. Contractual terms are predicted by the Nash bargaining solution and are distinguished from those in an ordinary bilateral monopoly because they make allowance for competing, vertically differentiated brands. The model predicts that differences in retailers’ ability to promote the manufacturer’s brand induce prices that vary systematically with the manufacturer’s market share of retailers’ sales.     

Relative price changes and deviations from purchasing power parity

During recent years, exchange rate fluctuations have exceeded variation in price indices. As a result, a number of theories have been developed to explain the apparent ‘overshooting’ of the exchange rate. The purpose of this paper is to argue that such elaborate extensions may be unnecessary, because the law of one price is more robust than previously believed. In particular, it can be shown that the law of one price is consistent with the observed variability of exchange rates and that it outperforms the overshooting models in explaining the stochastic behavior of exchange rates and interest rates.     

Asymmetric information and portfolio performance measurement

This note argues that though Dave Mayers and Edward Rice were able to show that the CAPM could be used to detect superior investors in a world of asymmetric information, their demonstration does not resurrect the CAPM as a practical tool for performance measurement. To employ the Mayers-Rice model, an investment advisor would first have to determine that the CAPM holds for uninformed investors. As a means of avoiding the problem of testing the CAPM, a performance measure based only on returns is outlined. The measure is robust in that it would correctly designate superior investors in context of the CAPM, the arbitrage pricing model and many other equilibrium models of security pricing.