基于Copula函数的秩相关和尾相关研究

变量间的相关结构是考察变量联合分布特征的首要任务。最经典的是线性相关系数,然而由于线性相关系数是建立在正态分布假设基础上的,存在着很多的局限性,所以,引入了用Copula函数表示的秩相关和尾相关测度。用Copula函数表示的秩相关和尾相关测度比较稳健,不易受极端值影响,且不需要正态分布假设。最后通过模拟得到了上市公司t-Cop-ula的秩相关和尾相关测度。     

Forecasting US real house price returns over 1831–2013: evidence from copula models

Given the existence of nonnormality and nonlinearity in the data generating process of real house price returns over the period of 1831–2013, this article compares the ability of various univariate copula models, relative to standard benchmarks (naive and autoregressive models) in forecasting real US house price over the annual out-of-sample period of 1874–2013, based on an in-sample of 1831–1873. Overall, our results provide overwhelming evidence in favour of the copula models (Normal, Student’s t, Clayton, Frank, Gumbel, Joe and Ali-Mikhail-Huq) relative to linear benchmarks, and especially for the Student’s t-copula, which outperforms all other models both in terms of in-sample and out-of-sample predictability results. Our results highlight the importance of accounting for nonnormality and nonlinearity in the data generating process of real house price returns for the US economy for nearly two centuries of data.     

Fairness, price stickiness, and history dependence in decentralized trade

The paper investigates price formation in a decentralized market with random matching. Agents are assumed to have subdued social preferences: buyers, for example, prefer a lower price to a higher one but experience reduced utility increases below a reference price that serves as a common fairness benchmark. The strategic equilibrium reflects market fundamentals, but it is markedly less sensitive to the buyer–seller ratio near the fair price benchmark. Prices may be sticky around very different reference levels in markets with otherwise identical fundamentals. The implied history dependence turns out to be mitigated rather than exacerbated by friction.     

Dependence structure between nominal and index-linked bond returns: a bivariate copula and DCC-GARCH approach

This article investigates the dependence structure related to four French nominal and index-linked bonds with various maturities and reference indices. To achieve this aim, we estimate various copulas to select the appropriate one for our data. We also compare results obtained using the copula method with multivariate dynamic conditional correlation GARCH (DCC-GARCH) modelling. The major issue in this study is that the best copulas used to model the dependence among bond returns are the Plackett and Student models. We also find a dynamic correlation between bond returns. In particular, the relationship between nominal and indexed bonds is characterized by an asymmetric dependence. Moreover, the results obtained by the copula approach are confirmed by those obtained by multivariate GARCH modelling. Our empirical study provides a useful method that may be employed by decision-makers to quantitatively introduce dependence and spillover effects in their bond issuance policy. For investors, we propose optimal investment combinations in bonds with respect to their investment horizons.     

Directional time-varying partial correlation with the Gaussian copula–DCC–GARCH model

This article suggests a directional time-varying partial correlation based on the dynamic conditional correlation (DCC) method. A recent study proposed the copula DCC based on the vine structure. Due to the arbitrary variable selection, their method can produce unnecessary dependence in the multivariate structure, with extra economic and computational burdens. To overcome this limitation, we incorporate directional dependence by copula to track the causal relationship among multiple variables and then extend the copula bivariate DCC method to a directional time varying partial correlation in the multivariate structure. Our proposed method provides a reasonable and efficient conditional dependence structure, without the trial and error process. We offer an application of our method to the U.S. stock market as an illustrated example.     

Tail dependence and diversification benefits in emerging market stocks: an extreme value theory approach

This article examines tail dependence, the benefits of diversification and the relation between the two for emerging stock markets. We find most emerging equity markets are independent in limiting joint extremes. However, the dependence in finite levels of extremes is still much stronger than the dependence implied by multivariate normality. Therefore, simple correlation analysis can lead to gross underestimation of the chances of joint crashes in multiple markets. Assuming risk-averse investors guarding against extreme losses, diversification benefits are measured for each two-country optimal portfolio by the reduction in quantile risk measures such as value-at-risk and expected shortfall relative to an undiversified portfolio. It is shown that tail dependence measures developed from multivariate extreme value theory are negatively related to diversification benefits and more importantly can explain diversification benefits better than the correlation coefficient at the most extreme quantiles.     

关于地租推进型通货膨胀的价格传导机制研究

本文认为,地租推进型通货膨胀是土地产品价格上涨推动的通货膨胀,是土地产品价值上升的结果,是土地产品价值实现的要求,不是传统意义上的通货膨胀。不同类型的货币政策下,尽管地租推进型通货膨胀的价格传导机制是不同的,其基本内容都是剩余产品在初次分配中向土地所有者的倾斜。因此,地租推进型通货膨胀的治理,核心不在于消灭地租推进型通货膨胀本身,而在于缓解收入分配带来的社会阵痛。地租推进型通货膨胀在投机资本的影响下往往呈现复合式发展的特征。地租推进型通货膨胀研究的新视角,为政府宏观调控应对土地产品价格上涨提供了全新的思路。     

Price transmission in cross boundary supply chains

The extent to which demand and supply shocks are transmitted in the supply chain is an important topic. As many supply chains cross international borders exchange rate pass through is an important element in this context. In this paper a multivariate system that allow us to test different hypothesis with respect to the supply chain is specified. Our empirical analysis includes tests of whether there is a link between the different stages in the supply chain, whether the exchange rate pass through is complete and whether price signals are fully transmitted. Different exogeneity assumptions are testable hypothesis, and one can avoid the simultaneity problem associated with the common single equation specifications. Moreover, one can also test whether the exchange rate is determined outside the system, as well as testing for price leadership. An application is provided for the supply chain for cod between Norway and Portugal.

Time-varying transmission efficiency of China’s monetary policy

This paper tries to investigate the time-varying characteristics of China’s monetary policy transmission from the impulse response evidence of both open-economy DSGE model and TVP-VAR model. We find that the transmission efficiency of price-based monetary policy has significantly improved over the sample period, while quantity-based monetary policy is weakening. The resume of exchange reform in 2010 also strengthens the exchange rate channel especially in terms of price-based monetary policy. Combining with the evidence from DSGE model underlines the importance of further interest rate liberalization and price-based monetary policy Taylor rule should also consider the exchange rate stability.     

Dynamic multiproduct optimal hedging in the soybean complex – do time-varying correlations provide hedging improvements?

Optimal multiproduct time-varying hedge ratios are determined – for a soybean complex – and their risk-mitigating impact is contrasted over single-commodity time-varying and naive hedge ratios. A parsimonious regime-switching dynamic correlation model is employed, with the estimated dynamic correlation matrix among prices varying between two different levels, and the time-varying correlations being applied to the multiproduct setting. Findings obtained are three-fold. First, there is significant evidence that estimated simultaneous correlations among different commodities’ prices (e.g. soybean spot and soybean meal futures) attain different values along the time series. Second, there is a substantial reduction in margin variance provided by the optimal multiproduct time-varying hedge ratios over single time-varying and naive hedge ratios, for both in- and out-of-sample data. Third, average optimal multiproduct time-varying hedge ratios for soybean and soybean meal (0.82 and 0.74, respectively; for out-of-sample data) are significantly below the naive full hedge ratio, providing risk mitigation at lower costs.