出口信用保险对我国出口贸易影响的实证分析——基于与出口退税因素比较之视角

出口作为拉动经济发展的三驾马车之一,在我国经济发展中起到举足轻重的作用,为了促进出口贸易的发展,我国实施了多项出口贸易鼓励政策。本文对出口退税、出口信用保险、出口贸易三个变量进行协整分析,并通过VAR模型估计以及脉冲响应函数及方差分解的实证分析,得出三个变量的相互关系;同时通过两个因素的实证比较,得出出口信用保险虽然在短期内对出口贸易的影响还不够显著,但从长期看却是显著的,并且要大于出口退税对出口贸易的影响程度,最后提出发展我国出口信用保险的政策建议。     

Nexus between telecommunication infrastructures,economic growth and development in Africa: Panel vector autoregression (P-VAR) analysis

This study examines the causal-effect relationship between telecommunication infrastructures, economic growth and development in selected African countries. It further estimates the trivariate impacts of telecommunication infrastructures, economic growth and development in the region. The analysis considers a panel of forty-six African countries from 2000 to 2015. To measure economic growth, real gross domestic product serves as the proxy, while economic development is measured by the Human Development Index, and telecommunication infrastructures by a composite index of telecommunication computed from mobile line, fixed line and internet access penetration via principal component analysis (PCA). The empirical results suggest the existence of a bidirectional long-run relationship between telecommunication infrastructures, economic growth and development. The causality tests reveal that there is feedback causality between telecommunication infrastructures, economic growth and development. Telecommunication infrastructures promote economic growth and development in Africa and vice versa. Thus, there is need to promote inclusive and holistic policies that will enhance digital provide, economic growth and development simultaneously in Africa. An increase in telecommunication infrastructures will encourage aggregate output and standard of living to move in the same direction in Africa.     

Measuring the increasing connectedness of Chinese assets with global assets: using a variance decompositions method

This study uses the network topology of variance decompositions to investigate the connectedness of four assets (stocks, bonds, foreign exchange and commodities) across five countries (US, EU, UK, Japan and China). We find that connectedness to and from the Chinese asset markets increased significantly from 2013 to 2018, which reveals that Chinese assets have gradually become integrated into the global economy. We also investigate the volatility connectedness in economically fragile periods and find that the Chinese market acted as a transmitter of volatility in the 2015 Chinese stock crash. This finding is potentially essential to modern risk measurement and management.     

Inferring volatility dynamics and risk premia from the S&P 500 and VIX markets

We estimate a flexible affine model using an unbalanced panel containing S&P 500 and VIX index returns and option prices and analyze the contribution of VIX options to the model’s in- and out-of-sample performance. We find that they contain valuable information on the risk-neutral conditional distributions of volatility at different time horizons, which is not spanned by the S&P 500 market. This information allows enhanced estimation of the variance risk premium. We gain new insights on the term structure of the variance risk premium, present a trading strategy exploiting these insights, and show how to improve S&P 500 return forecasts.     

中国城镇化发展与农民收入增长关系的动态计量经济分析

本文在建立向量自回归模型的基础上，运用脉冲响应函数和预测方差分解来刻画城镇化发展与农民收入增长之间的动态相关性。研究结论表明，我国城镇化发展与农民收入增长之间存在着较强的正向交互响应作用，而且其长期的响应作用程度更显著、更稳定。因此，在当前条件下，加速推进城镇化进程是持续增加农民收入的根本路径选择和重要途径。在采用城镇化发展促进农民收入增长的政策选择上，应采取长期政策而非短期政策。     

Bootstrapping Financial Time Series

It is well known that time series of returns are characterized by volatility clustering and excess kurtosis. Therefore, when modelling the dynamic behavior of returns, inference and prediction methods, based on independent and/or Gaussian observations may be inadequate. As bootstrap methods are not, in general, based on any particular assumption on the distribution of the data, they are well suited for the analysis of returns. This paper reviews the application of bootstrap procedures for inference and prediction of financial time series. In relation to inference, bootstrap techniques have been applied to obtain the sample distribution of statistics for testing, for example, autoregressive dynamics in the conditional mean and variance, unit roots in the mean, fractional integration in volatility and the predictive ability of technical trading rules. On the other hand, bootstrap procedures have been used to estimate the distribution of returns which is of interest, for example, for Value at Risk (VaR) models or for prediction purposes. Although the application of bootstrap techniques to the empirical analysis of financial time series is very broad, there are few analytical results on the statistical properties of these techniques when applied to heteroscedastic time series. Furthermore, there are quite a few papers where the bootstrap procedures used are not adequate.     

Estimation in Two-Stage Models with Heteroscedasticity

A surprising number of important problems can be cast in the framework of estimating a mean and variance using data arising from a two-stage structure. The first stage is a random sampling of "units" with some quantity of interest associated with the unit. The second stage produces an estimate of that quantity and usually, but not always, an estimated standard error, which may change considerably across units. Heteroscedasticity in the estimates over different units can arise for a number of reasons, including variation associated with the unit and changing sampling effort over units. This paper presents a broad discussion of the problem of making inferences for the population mean and variance associated with the unobserved true values at the first stage of sampling. A careful discussion of the causes of heteroscedasticity is given, followed by an examination of ways in which inferences can be carried out in a manner that is robust to the nature of the within unit heteroscedasticity. Among the conclusions are that under any type of heteroscedasticity, an unbiased estimate of the mean and the variance of the estimated mean can be obtained by using the estimates as if they were true unobserved values from the first stage. The issue of using the mean versus a weighted average which tries to account for the heteroscedasticity is also discussed. An unbiased estimate of the population variance is given and the variance of this estimate and its covariance with the estimated mean is provided under various types of heteroscedasticity. The two-stage setting arises in many contexts including the one-way random effects models with replication, meta-analysis, multi-stage sampling from finite populations and random coefficients models. We will motivate and illustrate the problem with data arising from these various contexts with the goal of providing a unified framework for addressing such problems.     

Pricing and hedging contingent claims using variance and higher order moment swaps

This paper suggests perfect hedging strategies of contingent claims under stochastic volatility and random jumps of the underlying asset price. This is done by enlarging the market with appropriate swaps whose pay-offs depend on higher order sample moments of the asset price process. Using European options and variance swaps, as well as barrier options written on the S&P 500 index, the paper provides clear cut evidence that hedging strategies employing variance and higher order moment swaps considerably improves upon the performance of traditional delta hedging strategies. Inclusion of the third-order moment swap improves upon the performance of variance swap-based strategies to hedge against random jumps. This result is more profound for short-term out-of-the money put options.     

财政政策与货币政策对私人投资的影响研究——基于有向无环图的应用分析

结合最新发展的"有向无环图"(DAG)技术,本文研究我国财政与货币政策对私人投资的影响,并考察政策工具在传导过程中的有效性及其动态关系。研究结果表明,尽管"信贷渠道"在我国货币政策传导中发挥着主导作用,但由于货币到信贷传导环节的断裂,使得"信贷渠道"自身存在着较大的政策局限性,与此同时,财政政策对私人投资的影响具有较强的独立性和有效性。递归的预测方差分解分析则表明本文结论是稳健的。在此研究过程中,最新DAG技术的运用不仅增进了我们对政策变量与实体经济部门"同期因果关系"的理解,而且克服了Granger因果检验等传统研究方法的局限性,进而在很大程度上增强了本文分析框架的有效性与合理性,并为我国未来宏观调控政策的选择与安排提供了重要的参考依据。     

Variance swaps,non-normality and macroeconomic and financial risks

This paper studies the determinants of the variance risk premium and discusses the hedging possibilities offered by variance swaps. We start by showing that the variance risk premium responds to changes in higher order moments of the distribution of market returns. But the uncertainty that determines the variance risk premium – the fear by investors to deviations from normality in returns – is also strongly related to a variety of macroeconomic and financial risks associated with default, employment growth, consumption growth, stock market and market illiquidity risks. We conclude that the variance risk premium reflects the market willingness to pay for hedging against these financial and macroeconomic sources of risk. An out-of-sample asset allocation exercise shows that the inclusion of the variance swap reduces the modified value-at-risk with respect to a portfolio holding exclusively the equity market portfolio.