Capturing the Spillover Effect With Multiplicative Error Models

Recent statistical models for the analysis of volatility in financial markets serve the purpose of incorporating the effect of other markets in their structure, in order to study the spillover or the contagion phenomena. Extending the Multiplicative Error Model we are able to capture these characteristics, under the assumption that the conditional mean of the volatility can be decomposed into the sum of one component representing the proper volatility of the time series analyzed, and other components, each representing the volatility transmitted from one other market. Each component follows a proper dynamics with elements that can be usefully interpreted. This particular decomposition allows to establish, each time, the contribution brought by each individual market to the global volatility of the market object of the analysis. We experiment this model with four stock indices.     

A Bayesian Markov-Switching Correlation Model for Contagion Analysis on Exchange Rate Markets

This article develops a new Markov-switching vector autoregressive (VAR) model with stochastic correlation for contagion analysis on financial markets. The correlation and the log-volatility dynamics are driven by two independent Markov chains, thus allowing for different effects such as volatility spill-overs and correlation shifts with various degrees of intensity. We outline a suitable Bayesian inference procedure based on Markov chain Monte Carlo algorithms. We then apply the model to some major and Asian-Pacific cross rates against the U.S. dollar and find strong evidence supporting the existence of contagion effects and correlation drops during crises, closely in line with the stylized facts outlined in the contagion literature. A comparison of this model with its closest competitors, such as a time-varying parameter VAR, reveals that our model has a better predictive ability. Supplementary materials for this article are available online     

Fundamentals and asset price dynamics

The relation between fundamentals and asset returns is analyzed by means of Markov-switching regression models with time-varying transition probabilities. By referring to the Italian Stock Exchange over the 1973-2002 period, we find that (i) returns switch between a zero-expected return/low volatility state and a high expected return/high volatility state; (ii) states are persistent and hence state changes can be forecast to some extent; (iii) the probability of state changes can be explained in terms of changes in the fundamentals; (iv) fundamentals do not have a direct impact on the expected returns but they only affect the transition probability matrix. Overall, our results show that a non-linear relation between market price changes and market fundamentals can be caught within the framework of (Markov) switching regession models.A previous draft of the paper was presented at the XL Scientific Meeting of The Italian Statistical Society, Firenze, April 2000. We would like to thank Maurizio Vichi (the editor) and several anonymous referees for important suggestions. A special thank to Lorenzo Sevini for valuable research assistance. Partial financial support by Italian M.I.U.R. grants is gratefully acknowledged.     

Common-factor stochastic volatility modelling with observable proxy

Multi-asset modelling is of fundamental importance to financial applications such as risk management and portfolio selection. In this article, we propose a multivariate stochastic volatility modelling framework with a parsimonious and interpretable correlation structure. Building on well-established evidence of common volatility factors among individual assets, we consider a multivariate diffusion process with a common-factor structure in the volatility innovations. Upon substituting an observable market proxy for the common volatility factor, we markedly improve the estimation of several model parameters and latent volatilities. The model is applied to a portfolio of several important constituents of the S&P500 in the financial sector, with the VIX index as the common-factor proxy. We find that the prediction intervals for asset forecasts are comparable to those of more complex dependence models, but that option-pricing uncertainty can be greatly reduced by adopting a common-volatility structure. The Canadian Journal of Statistics 48: 36–61; 2020 © 2020 Statistical Society of Canada     

经济政策不确定性如何影响金融市场间的流动性协同运动？——基于中国金融周期的视角

金融市场间流动性出现高协同运动是发生危机传染的重要表现之一，因此，针对流动性动态联动效应的研究显得极为重要。本文基于中国金融市场数据测算了2003-2018年间我国股市、债市流动性，并对Colacito等（2011）的混频数据抽样动态条件相关系数模型（DCC-MIDAS）进行了扩展，同时从金融周期视角出发，运用扩展后的模型考察了经济不确定性在不同时间区间内对于流动性波动率和相关性是否存在不同的作用效果。研究结果表明，相较于单因子混频模型，引入经济政策不确定性的多因子混频模型可以更好地捕捉我国股债两市相关性的动态变化；同时，经济政策不确定性的提高会降低股债两市流动性的正相关性，但这一作用效果会在金融周期的拐点处转为加强两者的正相关性。本文不仅为讨论股债两市联动效应提供了流动性的新视角，也为金融市场风险监管提供了重要的参考依据。     

Regime switching: Italian financial markets over a century

The frequency of crashes and the magnitude of crises in international financial markets are growing more severe over time. Recent financial crises are not singular events portrayed in recent accounts, rather, they erupt in circumstances that are very similar to the economic and financial environments of the earlier eras. This paper analyzes the Italian stock market in two very peculiar periods (1901–1911 and 1993–2004): the “Second” and the “Third industrial revolution”. We use Markov Switching Models to test whether the Italian stock market volatility has increased in the long run and whether it can be represented by different regimes. We find that volatility regimes exist; that Banking sector has a central role and “New economy” sectors perform quite well while traditional sectors do not, in both periods. I am grateful to comments from Giampiero M. Gallo, Christian T. Brownlees, Marco J. Lombardi, Renato Giannetti and from participants in the 2005 S.Co. Conference in Bressanone, especially the discussant Francesco Lisi. Thanks are also due to two anonymous referees that strongly helped improve the overall structure and readability of the paper.     

Stochastic Volatility Models Based on OU-Gamma Time Change: Theory and Estimation

We consider stochastic volatility models that are defined by an Ornstein–Uhlenbeck (OU)-Gamma time change. These models are most suitable for modeling financial time series and follow the general framework of the popular non-Gaussian OU models of Barndorff-Nielsen and Shephard. One current problem of these otherwise attractive nontrivial models is, in general, the unavailability of a tractable likelihood-based statistical analysis for the returns of financial assets, which requires the ability to sample from a nontrivial joint distribution. We show that an OU process driven by an infinite activity Gamma process, which is an OU-Gamma process, exhibits unique features, which allows one to explicitly describe and exactly sample from relevant joint distributions. This is a consequence of the OU structure and the calculus of Gamma and Dirichlet processes. We develop a particle marginal Metropolis–Hastings algorithm for this type of continuous-time stochastic volatility models and check its performance using simulated data. For illustration we finally fit the model to S&P500 index data.     

FORECASTING VOLATILITY IN THE PRESENCE OF MODEL INSTABILITY

Recent advances in financial econometrics have allowed for the construction of efficient ex post measures of daily volatility. This paper investigates the importance of instability in models of realised volatility and their corresponding forecasts. Testing for model instability is conducted with a subsampling method. We show that removing structurally unstable data of a short duration has a negligible impact on the accuracy of conditional mean forecasts of volatility. In contrast, it does provide a substantial improvement in a model's forecast density of volatility. In addition, the forecasting performance improves, often dramatically, when we evaluate models on structurally stable data.     

股市危机中股指期货应该限制交易吗——基于2015年股市危机的实证分析

利用上证50、沪深300和中证500股指期货合约及其相应指数的高频数据,克服了传统BEKK和DCC模型的不足,通过建立VECM-DCC-VARMA-AGARCH模型考察股市危机期间中国股指期货市场与股票市场之间的信息传导关系与风险传染效应。研究结果表明,股市危机期间股指期货具有很强的价格引导和风险传染效应,股指期货的持续波动加剧了股票市场的进一步波动。因此,提出风险传染效应与市值规模相关、非对称效应和非预期冲击效应与市值规模负相关、波动的风险传染效应与市值规模正相关。危机时期,应抑制股指期货市场上的过度投机,对股指期货采取限制开仓、提高交易保证金和交易手续费都是正确和切实可行的措施。建议监管当局健全股指期货和股票市场交易制度。     

金融危机传染效应的资产动态组合视角解析

由金融危机三阶段视角透视跨国投资组合供需动态变化过程中金融危机的传染特性。以跨国投资者投资决策与投资业绩互动为突破点,剖析在金融危机三阶段内调整跨国资产组合配置的微观交易行为所引致的金融危机传染性。经由9个国家金融危机期间基金交易数据的计量检验得出：金融危机中跨国投资者资产组合再分配是金融危机重要的传染渠道;与金融危机发源国分享风险偏好型跨国投资者的国家最容易被危机感染;金融危机三阶段传染效应的强度呈动态变化;金融市场上投资者的信息搜集在化解市场风险方面具有重要作用。     

Fractionally integrated GARCH model with tempered stable distribution: a simulation study

With the growing availability of high-frequency data, long memory has become a popular topic in finance research. Fractionally Integrated GARCH (FIGARCH) model is a standard approach to study the long memory of financial volatility. The original specification of FIGARCH model is developed using Normal distribution, which cannot accommodate fat-tailed properties commonly existing in financial time series. Traditionally, the Student-t distribution and General Error Distribution (GED) are used instead to solve that problem. However, a recent study points out that the Student-t lacks stability. Instead, the Stable distribution is introduced. The issue of this distribution is that its second moment does not exist. To overcome this new problem, the tempered stable distribution, which retains most attractive characteristics of the Stable distribution and has defined moments, is a natural candidate. In this paper, we describe the estimation procedure of the FIGARCH model with tempered stable distribution and conduct a series of simulation studies to demonstrate that it consistently outperforms FIGARCH models with the Normal, Student-t and GED distributions. An empirical evidence of the S&P 500 hourly return is also provided with robust results. Therefore, we argue that the tempered stable distribution could be a widely useful tool for modelling the high-frequency financial volatility in general contexts with a FIGARCH-type specification.     

Bayesian Estimation and Prediction of Stochastic Volatility Models via INLA

In this article, we assess Bayesian estimation and prediction using integrated Laplace approximation (INLA) on a stochastic volatility (SV) model. This was performed through a Monte Carlo study with 1,000 simulated time series. To evaluate the estimation method, two criteria were considered: the bias and square root of the mean square error (smse). The criteria used for prediction are the one step ahead forecast of volatility and the one day Value at Risk (VaR). The main findings are that the INLA approximations are fairly accurate and relatively robust to the choice of prior distribution on the persistence parameter. Additionally, VaR estimates are computed and compared for three financial time series returns indexes.     

Financial contagion through space-time point processes

Statistical Methods & Applications - We propose to study the dynamics of financial contagion by means of a class of point process models employed in the modeling of seismic contagion. The...     

Factor stochastic volatility with time varying loadings and Markov switching regimes

We generalize the factor stochastic volatility (FSV) model of Pitt and Shephard [1999. Time varying covariances: a factor stochastic volatility approach (with discussion). In: Bernardo, J.M., Berger, J.O., Dawid, A.P., Smith, A.F.M. (Eds.), Bayesian Statistics, vol. 6, Oxford University Press, London, pp. 547–570.] and Aguilar and West [2000. Bayesian dynamic factor models and variance matrix discounting for portfolio allocation. J. Business Econom. Statist. 18, 338–357.] in two important directions. First, we make the FSV model more flexible and able to capture more general time-varying variance–covariance structures by letting the matrix of factor loadings to be time dependent. Secondly, we entertain FSV models with jumps in the common factors volatilities through So, Lam and Li's [1998. A stochastic volatility model with Markov switching. J. Business Econom. Statist. 16, 244–253.] Markov switching stochastic volatility model. Novel Markov Chain Monte Carlo algorithms are derived for both classes of models. We apply our methodology to two illustrative situations: daily exchange rate returns [Aguilar, O., West, M., 2000. Bayesian dynamic factor models and variance matrix discounting for portfolio allocation. J. Business Econom. Statist. 18, 338–357.] and Latin American stock returns [Lopes, H.F., Migon, H.S., 2002. Comovements and contagion in emergent markets: stock indexes volatilities. In: Gatsonis, C., Kass, R.E., Carriquiry, A.L., Gelman, A., Verdinelli, I. Pauler, D., Higdon, D. (Eds.), Case Studies in Bayesian Statistics, vol. 6, pp. 287–302].     

A Comparison of the Runs Test for Volatility Forecastability and the LM Test for GARCH Using Aggregated Returns

Christoffersen and Diebold (2000 Christoffersen , P. F. , Diebold , F. X. ( 2000 ). How relevant is volatility forecasting for financial risk management? Review of Economics and Statistics 82 : 12 – 22 .[Crossref] , [Google Scholar]) have introduced a runs test for forecastable volatility in aggregated returns. In this note, we compare the size and power of their runs test and the more conventional LM test for GARCH by Monte Carlo simulation. When the true daily process is GARCH, EGARCH, or stochastic volatility, the LM test has better power than the runs test for the moderate-horizon returns considered by Christoffersen and Diebold. For long-horizon returns, however, the tests have very similar power. We also consider a qualitative threshold GARCH model. For this process, we find that the runs test has greater power than the LM test. Theresults support the use of the runs test with aggregated returns.     

A New Approach to Volatility Modeling: The Factorial Hidden Markov Volatility Model

A new process—the factorial hidden Markov volatility (FHMV) model—is proposed to model financial returns or realized variances. Its dynamics are driven by a latent volatility process specified as a product of three components: a Markov chain controlling volatility persistence, an independent discrete process capable of generating jumps in the volatility, and a predictable (data-driven) process capturing the leverage effect. An economic interpretation is attached to each one of these components. Moreover, the Markov chain and jump components allow volatility to switch abruptly between thousands of states, and the transition matrix of the model is structured to generate a high degree of volatility persistence. An empirical study on six financial time series shows that the FHMV process compares favorably to state-of-the-art volatility models in terms of in-sample fit and out-of-sample forecasting performance over time horizons ranging from 1 to 100 days. Supplementary materials for this article are available online.     

基于可拓模型的高科技上市公司财务风险预警研究

高科技上市公司由于行业特点,其经营业绩容易产生波动,因此建立高科技上市公司风险预警模型一直是国内外学者研究的焦点。根据可拓学的相关理论,选取高科技上市公司的相关财务指标建立高科技上市公司财务风险可拓预警模型,运用现有公开数据对可拓预警模型加以检验,并对下一年度有可能出现风险的公司加以预警,以期望能够为投资者的决策分析和监管部门的监督管理提供理论参考。     

预期引导、政策冲击与股市波动——基于文本分析法的异质性诊断

防范股票市场异常波动是维护金融稳定和防控金融风险的关键一环。货币政策实践中,预期引导与政策冲击对股市波动的实际影响和传导机制迥然不同。现有文献对两者之于股票市场波动 的异质性影响多有讨论,但分歧明显。基于2005年到2019年中国人民银行各季度《货币政策执行报告》和《货币政策大事记》,本文分别构建表征货币政策预期引导强度和实际操作频度的代理变量,对上述指标之于同期A股市场主要行业指数的波动性影响做了多维诊断和系统梳理。研究发现,第一,预期引导效应和政策冲击效应对于股票市场波动性的影响存在显著异质性特征,预期引导有助于平抑市场波动,而频繁调控则会放大股市波动。第二,预期引导的明确性会制约其对股市波动的平缓作用,货币调控意愿的表达越明确,越有助于平抑股票市场波动;而更坚决的“严厉型”表述比态度相对温和的“温和型”表述能够更显著地平抑股票市场波动。第三,实际操作频度对股市波动的放大作用受制于具体调控方向,宽松型调控的频率上升仅会小幅放大股市波动,而紧缩型货币调控则会大幅抬升股市波动性。由此,从平抑股市异常波动、维持金融稳定的角度出发,强化货币政策的预期引导比相机抉择的频繁调控更为重要;在预期引导过程中,应当增强调控意愿表达的明确性和坚决性,以限制其对金融市场运行带来的扰动。     

The Volatility of Realized Volatility

In recent years, with the availability of high-frequency financial market data modeling realized volatility has become a new and innovative research direction. The construction of “observable” or realized volatility series from intra-day transaction data and the use of standard time-series techniques has lead to promising strategies for modeling and predicting (daily) volatility. In this article, we show that the residuals of commonly used time-series models for realized volatility and logarithmic realized variance exhibit non-Gaussianity and volatility clustering. We propose extensions to explicitly account for these properties and assess their relevance for modeling and forecasting realized volatility. In an empirical application for S&P 500 index futures we show that allowing for time-varying volatility of realized volatility and logarithmic realized variance substantially improves the fit as well as predictive performance. Furthermore, the distributional assumption for residuals plays a crucial role in density forecasting.     

The Volatility of Realized Volatility

In recent years, with the availability of high-frequency financial market data modeling realized volatility has become a new and innovative research direction. The construction of “observable” or realized volatility series from intra-day transaction data and the use of standard time-series techniques has lead to promising strategies for modeling and predicting (daily) volatility. In this article, we show that the residuals of commonly used time-series models for realized volatility and logarithmic realized variance exhibit non-Gaussianity and volatility clustering. We propose extensions to explicitly account for these properties and assess their relevance for modeling and forecasting realized volatility. In an empirical application for S&P 500 index futures we show that allowing for time-varying volatility of realized volatility and logarithmic realized variance substantially improves the fit as well as predictive performance. Furthermore, the distributional assumption for residuals plays a crucial role in density forecasting.