基于強(qiáng)Copula混合理論的股市風(fēng)險(xiǎn)實(shí)證分析
本文關(guān)鍵詞: 幾何加權(quán)平均混合Copula 最小二乘估計(jì) Gibbs抽樣 GARCH 出處:《華南理工大學(xué)》2013年碩士論文 論文類型:學(xué)位論文
【摘要】:隨著金融全球化和金融創(chuàng)新步伐的加快,金融市場(chǎng)的風(fēng)險(xiǎn)分析發(fā)展很快,Copula函數(shù)成為一種新興的金融分析工具。由于Copula可以捕捉變量間非線性、非對(duì)稱及尾部相關(guān)性,為投資者提供競(jìng)爭(zhēng)優(yōu)勢(shì)和可觀收益,故在國(guó)內(nèi)外得到廣泛應(yīng)用。但簡(jiǎn)單的Copula函數(shù)適合特殊情形的金融市場(chǎng),與現(xiàn)實(shí)復(fù)雜的金融市場(chǎng)仍存在較大差別;旌螩opula函數(shù)不僅可以用來(lái)描述股票市場(chǎng)之間上尾相關(guān)、下尾相關(guān)和對(duì)稱相關(guān)三種模式,還可以描述金融市場(chǎng)之間上尾、下尾相關(guān)并存的非對(duì)稱相關(guān)模式,與具有復(fù)雜相關(guān)關(guān)系的金融市場(chǎng)更加接近。而我們常見(jiàn)的是線性Copula混合模型,本文提出一種新的Copula混合模型-幾何加權(quán)平均混合模型。 本文的重點(diǎn)是要驗(yàn)證該混合模型在實(shí)證中的有效性。本文以2007年1月4日到2012年12月31日金融和地產(chǎn)日收盤(pán)價(jià)指數(shù)收益共1460組數(shù)據(jù)為例,從以下方面進(jìn)行模型構(gòu)建: (1)邊緣分布的確定。由于邊緣分布不是本文考察的重點(diǎn),故選取常用的GARCH(1,1)-t模型。但作為異方差模型必須首先進(jìn)行ARCH效應(yīng)檢驗(yàn),本文選取殘差平方的相關(guān)圖檢驗(yàn)法。 (2)Copula函數(shù)參數(shù)的確定。為了采用Genest and Rivest非參數(shù)估計(jì)單一Copula模型的參數(shù),本文總結(jié)出阿基米德Copula函數(shù)中kendall’s秩相關(guān)與參數(shù)的關(guān)系式。而混合模型中未知參數(shù)較多,,包括單一Copula函數(shù)中的參數(shù)和權(quán)重兩大類。針對(duì)參數(shù)的研究,本文提出了最小二乘估計(jì)法與Gibbs抽樣,有效地解決模型中參數(shù)確定問(wèn)題。 (3)模型的有效性檢驗(yàn)。通過(guò)聯(lián)合分布直接求VaR相對(duì)比較復(fù)雜,本文結(jié)合MonteCarlo模擬近似估計(jì)幾種模型的聯(lián)合分布VaR,并對(duì)它們分別進(jìn)行后驗(yàn)測(cè)試。 通過(guò)分析后驗(yàn)測(cè)試結(jié)果,我們發(fā)現(xiàn)相對(duì)單一Copula模型而言,該混合Copula模型的失效天數(shù)相對(duì)較少。作為一種新型的混合模型,它提高了風(fēng)險(xiǎn)預(yù)測(cè)的精度,從而比較真實(shí)地描述投資組合的風(fēng)險(xiǎn),具有一定的經(jīng)濟(jì)價(jià)值。
[Abstract]:With the acceleration of financial globalization and financial innovation, the risk analysis of financial markets has developed rapidly. Copula function has become a new financial analysis tool. Because Copula can capture the nonlinear, asymmetric and tail correlation between variables. It is widely used at home and abroad because it provides investors with competitive advantage and considerable income. But the simple Copula function is suitable for special financial market. The mixed Copula function can be used not only to describe the upper tail correlation, lower tail correlation and symmetric correlation among stock markets, but also to describe the upper tail of financial markets. The asymmetric correlation model with coexisting lower tail correlation is closer to the financial market with complex correlation, but we often use the linear Copula mixed model. In this paper, a new Copula hybrid model, geometric weighted average hybrid model, is proposed. The focus of this paper is to verify the validity of the hybrid model. This paper takes 1460 groups of financial and real estate daily closing index returns from January 4th 2007 to December 31st 2012 as an example to build the model from the following aspects:. (1) the determination of edge distribution. Because the edge distribution is not the focus of this paper, we select the commonly used GARCHN 1GARCHN 1T model. However, as a heteroscedasticity model, we must first test the ARCH effect, and select the correlation graph test method of the residual square in this paper. In order to use Genest and Rivest to estimate the parameters of a single Copula model, the relationship between kendall's rank correlation and parameters in Archimedes Copula function is summarized in this paper. There are two kinds of parameters and weights in a single Copula function. In this paper, the least square estimation method and Gibbs sampling are proposed to solve the problem of parameter determination in the model. It is relatively complex to obtain VaR directly by joint distribution. In this paper, the joint distribution of several models is estimated by using MonteCarlo simulation approximation, and a posteriori test is carried out on each model. By analyzing the results of a posteriori test, we find that the failure days of the hybrid Copula model are relatively small compared with a single Copula model. As a new hybrid model, it improves the accuracy of risk prediction. Therefore, it is of certain economic value to describe the risk of the investment portfolio more truthfully.
【學(xué)位授予單位】:華南理工大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2013
【分類號(hào)】:F830.91;O212.1
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