基于GARCH模型的上证指数与GDP波动性研究

中国的证券市场与宏观经济关系已进入弱相关阶段,本文通过使用ADF检验、ARCH效应检验、GARCH模型分析以及Granger检验对两者的波动性进行分析和研究。实证结果发现,中国的证券市场与宏观经济都具有非正态分布的特性。其次,证券市场不存在自回归条件异方差效应波动,宏观经济存在自回归条件异方差效应波动,并且GARCH(1,1)最适合描述宏观经济的自回归条件异方差效应波动,上证指数的预测与宏观经济的预测两者之间具有互相印证的关系。     

上海A、B股市场收益率波动性对比研究及预测

运用GARCH(1,1)-M模型对样本期内上海A、B股市场收益率波动性进行了对比研究及预测。结果显示:上证A、B股指数收益率序列均存在"ARCH/GARCH现象";上海A、B股市场中,期望收益与期望风险正向变动;上海A股市场记忆期长于B股市场;长期中,上海B股市场预期收益将超过A股市场。进一步结合基本面情况可知,上海B股市场具有相对较高的长线投资价值。     

CHANGE IN VOLATILITY REGIMES AND DIVERSIFICATION IN EMERGING STOCK MARKETS

A multivariate Markov-switching ARCH (MVSWARCH) model in which variance/correlations for stock returns is controlled by a state-varying mechanism is introduced and used to design a state-varying US-EM (emerging market) portfolio establishment strategy. Additionally, a conventional random-variance framework, the MVGARCH (multivariate GARCH) model, in which a time-varying technique is involved is employed and subjected to comparative analysis. The empirical results are consistent with the following notions: First, as being consistent with a study conducted by Ramchand and Susmel , the US-EM market correlations are higher when the US market is more volatile. However, this study further indicates that the US-EM market correlations increase relatively more when both the US and EM markets simultaneously experience a high variance condition. Moreover, the situation of both the US and EM stock markets at a high volatility state is associated with a minimum risk reduction benefit and a maximum cross-market correlation. Second, the state-varying portfolio loadings established by the MVSWARCH model could effectively enhance asset allocation effectiveness; however, this benefit arises more as a result of risk reduction than an increase in mean returns.     

收益波动与随机冲击的非对称性影响：中国与美国股票市场的对比

通过讨论股票收益与随机;中击之间的关系,对中国股票市场和美国股票市场进行了对比研究。研究中使用了中国上海和深圳股票市场1990年12月31日至2005年12月30日的两市A股算术平均周指,以及美国股票市场1973年1月2日至2004年月12月30日的标准普尔500周指。在进行经验研究的过程中,分别使用了线性GARCH模型和GJR—GARCH模型计量股票收益的条件波动——即模型中的条件方差。研究发现,中国股票市场自1990年——1995年波动剧烈,之后波动趋于平缓,而美国股票市场在研究期间内收益波动一直处于一定范围内。同时还发现,美国股票市场的随机冲击对股票收益产生非对称性影响,即负冲击使股票收益产生的波动大于正冲击。而在中国股票市场却找不到相似的证据。鉴于对中国股票市场收益波动的研究结果,在剔除1996年以前的数据之后又进行了扩展研究,但是似然比率检验结果表明,正冲击对股票收益的影响还要略强于负冲击。     

A Review of Theoretical Results for ARCH-type Models

This paper provides a review of some theoretical results for ARCH-type models, and is directed towards practitioners. Starting with the simple ARCH model and proceeding to the GARCH model, various ARCH-type models, including exponential GARCH, threshold ARCH, ARCH-in-Mean and multivariate ARCH are reviewed.     

蔬菜价格波动特征研究——基于ARCH类模型分析

利用ARCH类模型研究蔬菜价格波动特征问题。结果表明:18种蔬菜具有价格波动集簇性和异方差性,其中冬瓜等6种蔬菜的价格具有显著的异方差效应和波动集簇性。GARCH模型表明6种蔬菜的价格波动都具有显著地集簇性,按价格波动持续性强弱比较,冬瓜、大白菜、土豆、洋葱的价格波动持续性强于青椒和生姜;GARCH-M模型表明只有土豆和生姜具有高风险高回报的特征;TARCH和EARCH模型表明6中蔬菜都具有显著的非对称效应,其中除洋葱和青椒以外,其他4种蔬菜两个模型的非对称效应都使得价格波动减小。     

On the Quantile Regression Based Tests for Asymmetry in Stock Return Volatility

This paper attempts to examine whether the asymmetry of stock return volatility varies with the level of volatility. Thus, quantile regression based tests (ρ-tests) are presupposed. These tests differ from the diagnostic tests introduced by Engle and Ng (1993) insofar as they can provide a complete picture of asymmetries in volatility across quantiles of variance distribution and, in case of non-normal errors, they have improved power due to their robustness against non-normality. A small Monte Carlo evidence suggests that the Wald and likelihood ratio (LR) tests out of ρ-tests are reasonable, showing that they outperform the Lagrange multiplier (LM) test based on least squares residuals when the innovations exhibit heavy tail. Using the normalized residuals obtained from AR(1)-GARCH(1, 1) estimation, the test results demonstrated that only the TOPIX out of six stock-return series had asymmetry in volatility at moderate level, while all stock return series except the FAZ and FA100 had more significant asymmetry in volatility at higher levels. Interestingly, it is clear from the empirical findings that, like hypothesis of leverage effects, volatility of the TOPIX, CAC40, and, MIB tends to respond significantly to extremely negative shock at high level, but is not correlated with any positive shock. These might be valuable findings that have not been seriously considered in past research, which has focussed only on mean level of volatility.     

Modeling the volatility of real GDP growth: The case of Japan revisited

Previous studies [e.g., Hamori, S., 2000. Volatility of real GDP: some evidence from the United States, the United Kingdom and Japan. Japan and the World Economy 12, 143–152; Ho, K.Y., Tsui, A.K.C., 2003. Asymmetric volatility of real GDP: some evidence from Canada, Japan, the United Kingdom and the United States. Japan and the World Economy 15, 437–445; Fountas, S., Karanasos, M., Mendoza, A., 2004. Output variability and economic growth: the Japanese case. Bulletin of Economic Research 56, 353–363] find high volatility persistence of economic growth rates using generalized autoregressive conditional heteroskedasticity (GARCH) specifications. This paper reexamines the Japanese case, using the same approach and showing that this finding of high volatility persistence reflects the Great Moderation, which features a sharp decline in the variance as well as two falls in the mean of the growth rates identified by Bai and Perron's [Bai, J., Perron, P., 1998. Estimating and testing linear models with multiple structural changes. Econometrica 66, 47–78; Bai, J., Perron, P., 2003. Computation and analysis of multiple structural change models. Journal of Applied Econometrics 18, 1–22] multiple structural change test. Our empirical results provide new evidence. First, excess kurtosis drops substantially or disappears in the GARCH or exponential GARCH model that corrects for an additive outlier. Second, using the outlier-corrected data, the integrated GARCH effect or high volatility persistence remains in the specification once we introduce intercept-shift dummies into the mean equation. Third, the time-varying variance falls sharply, only when we incorporate the break in the variance equation. Fourth, the ARCH in mean model finds no effects of our more correct measure of output volatility on output growth or of output growth on its volatility.     

基于GARCH模型的VaR方法在沪深300ETF风险测量的应用

交易所交易基金(ETF)在国际社会上被认为是长线投资、价值投资，规避风险的良好金融工具。中国股市投机炒作风气历来盛行，因此在投资领域有必要增强投资者对ETF的认知度和接受度。选用嘉实沪深300ETF作为研究对象，其所追踪的沪深300指数覆盖面广，基本体现中国沪深两市股市的收益状况。从其风险入手，运用GARCH模型研究分析得出该基金收益率的有效条件方差并结合VaR方法准确测量其风险价值，最终确定在95%的置信水平下GARCH(2,1)-t-分布模型能够最佳度量其风险价值。     

Seasonality and stock returns: some evidence from Japan

This paper examines the seasonal properties of Japanese stock prices using time series data from 1971 through 1997. Of interest are the influences of particular months of the year, which this study measures for the Tokyo stock price index (TOPIX), and indices that represent companies with large, medium, and small numbers of listed shares. The monthly effects in the various stock indices are confirmed for the total sample period. In contrast, such effects are not found for the latter half of the sample, and seasonal unit roots are rejected for all indices. That is, the seasonality of Japanese stock price indices is found to be deterministic but not stochastic.     

沪深股市收益率及波动性特征分析研究

中国金融市场的波动性从来都是备受关注的,本文对2000年1月4日～2010年5月26日沪深两市的收益率数据进行实证研究,得出中国金融市场收益率具有尖峰厚尾的特征和ARCH效应。并检验股市的溢出效应与杠杆效应等一系列特征,得出深市具有单向的溢出效应以及沪深两市具有正的杠杆效应。最后结合中国的股市现状给出相关分析与建议。     

中国创业板市场节日效应的实证分析

本文回顾了创业板市场建立过程,以香港创业板与深市创业板的时间序列数据,首先进行了香港创业板(GEM001)和深市创业板指(399006)对数收益率的波动性刻画,验证其分别服从GARCH(1,1)和ARCH(1)模型,且拟合优度较好;然后采用虚拟变量回归的方法,对其节日效应进行了检验,结果发现:港股在元旦、五一、春节时具有较为显著的节日效应(节前效应和节后效应);深创业板在国庆时具有较为明显的节日效应,在元旦和五一具有节前效应。最后针对创业板市场的关键问题,提出看法和建议。     

Investment strategies by foreign automobile firms in China: A comparative study of Volkswagen,Honda, and Hyundai

The paper uses rolling sample tests to investigate time-varying calendar effects in the Chinese stock market, based on the GARCH (1, 1)-GED model. The Friday effect existed with low volatility at the early stage, but it seems to have disappeared since 1997. The positive Tuesday effect began to appear then. There is a small-firm January effect with high volatility. The turn-of-the month effect has also disappeared in the Chinese stock market since 1997.     

Assessing the risk forecasts for Japanese stock market

We evaluate predictive performance of a selection of value-at-risk (VaR) models for Japanese stock market data. We consider traditional VaR models such as Riskmetrics method, historical simulation, variance–covariance method, Monte Carlo method, and their variants which are integrated with various ARCH models. Also considered are more recent models based on non-parametric quantile regression and extreme value theory (EVT). We apply these methods to the Japanese stock market index (1984–2000) and compare their performances in terms of various evaluation criteria using the method of White [Econometrica 68 (5) (2000) 1097–1126] for three out-of-sample periods of 1995–1996, 1997–1998, and 1999–2000.     

THE PREDICTABILITY OF STOCK MARKET RETURNS IN SOUTH AFRICA: PARAMETRIC VS. NON‐PARAMETRIC METHODS

This paper compares the forecasting performance of a sub‐class of univariate parametric and non‐parametric models in predicting stock market returns in South Africa. To account for conditional heteroskedasticity in stock returns data, the non‐parametric model is generated by the conditional heteroskedastic non‐linear autoregressive (NAR) model, while the parametric model is produced by the generalised autoregressive conditional heteroskedastic in mean (GARCH‐M) model. The results of the paper show that the NAR as a non‐parametric model performs better than the GARCH‐M model in short‐term forecasting horizon, and this indicates the importance of a distribution‐free model in predicting stock returns in South Africa.     

Do flexible exchange rates facilitate external adjustment? A dynamic approach with time-varying and asymmetric volatility

This paper revisits the claim that flexible exchange rates facilitate external adjustment. While previous studies have used exchange rate regime as a proxy for exchange rate flexibility, in this study there is evidence of ARCH effects in exchange rate, and thus GARCH models are employed to estimate volatility. A dynamic panel data model is then specified, and the Arellano-Bond estimator and the Blundell-Bond estimator are employed to estimate the effect of exchange rate flexibility on the speed of adjustment of current account in a panel of 28 emerging and developing economies. There is robust evidence that flexible exchange rates indeed facilitate smoother adjustment of current account imbalances.     

基于VaR-GARCH模型的中国商品期货动态保证金水平的设定

本文通过对中国大连商品交易所以及上海期货交易所黄豆、铜两种主要期货品种收益率的研究,论证了其时间序列存在ARCH效应;借助VaR风险价值法,运用GARCH模型,建立VaR-GARCH模型,计算出两合约每个交易日VaR风险预测值;计算黄豆0809合约和铜0809合约日涨跌停的绝对值,将其与VaR预测值进行比较,设定保证金水平,确定保证金率并与交易所规定的保证金率进行比较,为交易所制定更合理的期货保证金率提供依据。     

Volatility and Volume in Chinese Stock Markets

The fact that stock market returns in Europe and the USA are characterised by conditional heteroscedasticity is by now well documented in a large literature. We address the question of whether the same is true of the four Chinese stock markets (Shanghai and Shenzhen A and B) over the period from 25 November 1994 to 27 April 2001. Using daily index data, we make two departures from the standard GARCH(1,1) model. First, we use exponential GARCH (EGARCH) to allow for asymmetry in the volatility, which may be present as a result of leverage effects. Second, we respond to evidence of two-way causality between volume and return (and return volatility) by introducing a simultaneous equation model of the relationship. The results of estimating the model indicate that asymmetry does not seem to be present to a significant degree, possibly as a result of lack of information or concern among Chinese investors. We find that volume appears to play a significant part in determining index volatility, which may reflect information arrival effects or may alternatively result from the direct impact of trading on volatility. At the same time, we also find that both the level of returns and their conditional variance have an impact on trade volume, probably because positive (negative) returns tend to attract (deter) investors into the markets.     

备兑权证定价方法的务实改进与实现

为使备兑权证的定价更加贴近现实,文章以t分布代替原假设标的股票收益率服从的正态分布,以随机波动率代替历史波动率,通过GARCH模型来消除金融时间序列的异方差性,并考虑交易费用、红利等因素对权证价格的影响,在此优化了传统的定价模型。然后用Monte Carlo模拟的定价思路,并利用对偶方差减少技术提高其效率,最后编辑程序在Eviews中成功运行得出权证的定价.     

Volatility Spillovers between the US and China Stock Markets: Structural Break Test with Symmetric and Asymmetric GARCH Approaches

Abstract

The paper examines the short-run spillover effects of daily stock returns and volatilities between the Standard & Poor's (S&P) 500 stock index in the US and the Shanghai Stock Exchange (SSE) index in China. First, we find that a structural break occurred in the SSE stock return mean in December 2005. Second, by analyzing modified general autoregressive conditional heteroscedasticity (GARCH)(1,1)-M models, we find evidence of a symmetric and asymmetric volatility spillover effect from the US to the China stock market in the post-break period. Third, we observe the symmetric volatility spillover effect from China to the US in the post-break period.