Portfolio optimization based on GARCH-EVT-Copula forecasting models

This study uses GARCH-EVT-copula and ARMA-GARCH-EVT-copula models to perform out-of-sample forecasts and simulate one-day-ahead returns for ten stock indexes. We construct optimal portfolios based on the global minimum variance (GMV), minimum conditional value-at-risk (Min-CVaR) and certainty equivalence tangency (CET) criteria, and model the dependence structure between stock market returns by employing elliptical (Student-$t$ and Gaussian) and Archimedean (Clayton, Frank and Gumbel) copulas. We analyze the performances of 288 risk modeling portfolio strategies using out-of-sample back-testing. Our main finding is that the CET portfolio, based on ARMA-GARCH-EVT-copula forecasts, outperforms the benchmark portfolio based on historical returns. The regression analyses show that GARCH-EVT forecasting models, which use Gaussian or Student-$t$ copulas, are best at reducing the portfolio risk.     

基于CARR模型和GARCH模型的股市波动性预测研究

金融资产波动性建模和预测是金融理论与实践中的一个重要课题,已经有了许多建模与预测方法。本文利用我国股市的高频数据进行实证研究,分别运用CARP,模型和GARCH模型进行波动性预测,进而对两个模型的预测能力进行对比,结果表明：CARP,模型在波动性预测方面比GARCH模型的效果更好。     

商业银行现金持有量与宏观经济不确定性关系研究——基于面板数据的实证检验

本文研究了宏观经济不确定性对中国商业银行现金持有水平的影响。论文首先构建了一个GARCH模型得到代理变量来度量宏观经济不确定性,然后利用中国银行业2000～2009年的面板数据,实证检验了宏观经济不确定性对中国银行业现金持有水平的影响情况。实证结果表明:宏观经济不确定性对银行现金持有水平影响显著,当宏观经济不确定性增加、经济形势前景不明时,商业银行现金持有水平显著降低。     

商品市场的金融化对价格波动性的影响研究——以纽约商品交易所（NYMEX）WTI原油为例

本文致力于研究商品市场的金融化如何影响价格的波动性,特别是相对于对冲交易,投机交易将如何影响价格的波动性。在本文的实证应用方面,我们考虑的变量是原油期货价格,在这里我们使用纽约商品交易所（NYMEX）WTI原油相关的数据,非商业参与者的净价差,非商业参与者的净头寸,非商业参与者的头寸总额,非商业参与者的头寸和头寸总额的比率,和非商业参与者的头寸和期货市场交易量的比率。实证研究表明,非商业参与者的投机活动将会增加石油价格的波动性。或者把它放人一个更广泛的概念,石油的金融化使得石油更像是一种投资工具而不是一种商品,并增加了其价格的波动性。其次,经过一段频繁交易期之后,市场对价格趋势将会得到一些共同的看法,价格将会进人一个更加稳定的通道。当然这点可能由于数据问题需要进一步论证。     

MACROECONOMIC UNCERTAINTY AND CONDITIONAL STOCK MARKET VOLATILITY IN SOUTH AFRICA*

This paper analyses how systematic risk emanating from the macroeconomy is transmitted into stock market volatility using augmented autoregressive Generalised Autoregressive Conditional Heteroscedastic (AR‐GARCH) and vector autoregression (VAR) models. Also examined is whether the relationship between the two is bidirectional. By imposing dummies for the 1997‐1998 Asian and the 2007‐2009 sub‐prime financial crises, the study further analyses whether financial crises affect the relationship between macroeconomic uncertainty and stock market volatility. The findings show that macroeconomic uncertainty significantly influences stock market volatility. Although volatilities in inflation, the gold price and the oil price seem to play a role, it is found that volatility in short‐term interest rates and exchange rates are the most important, suggesting that South African domestic financial markets are increasingly becoming interdependent. Finally, the results show that financial crises increase volatility in the stock market and in most macroeconomic variables, and, by so doing, strengthen the effects of changes in macroeconomic variables on the stock market.     

Volatility Relationship between Crude Oil and Petroleum Products

This paper utilizes calculated historical volatility and GARCH models to compare the historical price volatility behavior of crude oil, motor gasoline and heating oil in U.S. markets since 1990. We incorporate a shift variable in the GARCH/TARCH models to capture the response of price volatility to a change in OPEC’s pricing behavior. This study has three major conclusions. First, there was an increase in volatility as a result of a structural shift to higher crude oil prices after April 1999. Second, volatility shocks from current news are not important since GARCH effects dominate ARCH effects in the variance equation. Third, persistence of volatility in all commodity markets is quite transitory, with half-lives normally being a few weeks.

中国和印度股市波动性的比较研究

作为“金砖四国”中的成员,中印两国股票市场具有较强的可比性。比较分析金融危机发生后两国的股市波动性特征,对中国股市发展具有理论和现实双重借鉴意义。文章利用ARCH族模型对上证综合指数和印度孟买30指数日收盘价数据展开实证研究,比较解析金融危机发生后中印两国的股市波动性特质,分析表明可变性和波动集簇性是两国收益率波动均呈现出的明显特质,而且印度比中国有更强的显示度;此外,中印两国股市收益正的风险溢价表现不显著;杠杆效应在上证综合指数收益率和印度孟买30指数收益率中均有体现,而且杠杆效应在印度股市的影响要高于中国股市。这对于确保中国股票和证券市场持续、稳定、强劲发展具有显著的理论说服力及重大的实践意义。     

消费者对生态标识食品的多层面认知行为:基于MVP模型的实证分析

笔者基于山东省693个样本数据,以绿色食品为例,将消费者认知行为划分为知晓、识别与使用三个层面,构建多变量Probit模型,分析在消费者认知程度提高过程中起主要作用的因素。研究发现,男性或年轻受访者在知晓层面的认知率较高,而女性、年长受访者在识别和使用层面的认知率相对较高;收入和卷入程度的影响在知晓层面不显著,而在识别和使用层面显著;学历、子女状况与环境保护意识的影响在各层面皆显著;食品安全意识与信息渠道的影响在较低层面显著,而在较高层面不显著。消费者认知行为的异质性为市场细分与开发提供了空间。厂商应针对不同群体采取差异化营销战略,引导消费者认知行为,促进潜在需求向现实需求转化。     

Jumps in the convenience yield of crude oil

The potential presence of jumps and time-varying volatility in convenience yields can lead to abnormally fat tails, which has implications for investment in storage capacity, leasing and drilling for crude oil. In this paper we evaluate the potential for these features in convenience yields. To that end, we analyze the rate of change in convenience yields for five futures prices time horizons (1, 3-, 6-, 9- and 12-month ahead), allowing for the both jumps and time-varying volatility. We find that both features exert a statistically important effect on convenience yields, for each of the five time horizons. We also calculate the implied probability that at least one jump would occur on any date, which reveals a period of relative calm at the start of the fracking boom, when large stockpiles built up at the trading hub for West Texas Intermediate, and a period of considerable churn, after the ban on exporting crude oil was lifted. Both elements underscore a linkage between inventory holdings and convenience yields.