美債危機對台股之傳染效果影響分析-ARMAX-GARCH-Copula Type模型之應用

The Contagion Effect Influence of US Debt Crisis on Taiwan Stock Market-Application of ARMAX-GARCH-Copula Type Model

高蕙芬(Hui-Fen Kao)

指導教授 ： 李沃牆

淡江大學/商學院/財務金融學系碩士在職專班/碩士(2012年)

https://doi.org/10.6846/TKU.2012.00733

摘要

本研究的目的在於檢驗台灣股市與美國股市之間在美債降評後是否存在傳染效果，研究除了採用ARMAX-GARCH-Copula Type模型驗證兩市場報酬率之關聯結構；並進一步運用雙變量GARCH模型評估美股與台股變異數的波動性。
實證結果發現，全樣本及降評前，考量不對稱性的ARMAX-EGARCH模型配適是適當的，而降評後的資料，基本統計量呈常態分配，以對稱性的ARMAX-GARCH模型配適是適當的。而美國十年期債券殖利率對於美股報酬率以及美股前期報酬率對台股報酬率，兩者的影響皆是正向的；不同消息面對市場衝擊呈現不對稱性的影響。
此外，台股與美股在降評後的相關性顯著提高，意函有短期的傳染效果，由t檢定發現美股與台股的動態相關程度在降評前後有顯著差異，亦即，美股與台股報酬率在降評後具外溢效果，且由雙變量GARCH模型可得，降評後的變異數明顯高於降評前，意函傳染效果顯著存在，但與過去全球性金融危機較長的蔓延效果相比則顯得較為輕微。

關鍵字

ARMAX-GARCH Type ； Copula ； 蔓延效果

並列摘要

The purpose of this study is to investigate whether a contagion effect exists between the Taiwan and US stock markets. In empirical study, we apply ARMAX-GARCH-Copula Type to check the correlation between the two markets, further to evaluate the volatility through Bivatiate GARCH model.
The results show that the asymmetric ARMAX-EGARCH model is more suitable, both in full sample or before the US debt rating downgrade. However, the symmetric ARMAX-GARCH model is more appropriate for normal distribution data after the downgrade.
The effect of the 10 year bond yield to US return rate and lag US return rate to Taiwan stock return rate are positive. It exhibits asymmetric results of different news to markets. In addition, there is a significant correlation between the Taiwan and US stock markets. It also implies a short-term contagion effect. The correlation of the two markets is significant before and during the US debt rating downgrading. It means that there is a spillover effect between the two markets. The volatility also increased after downgrading via bivariate GARCH model. It is different when compared with many global financial crises with a long contagion effect.

並列關鍵字

ARMAX-GARCH Type ； Copula ； Contagion effect

參考文獻

10. 聶建中、李文傳、洪榆雲(2004)，金融風暴前後對先進國家之股匯市連動關係變化影響，中華管理學報，第5卷第2期，頁19-35。

1. 王冠閔、黃柏農 (2004)，台灣股、匯市與美國股市關聯性探討，臺灣經濟

31. Wang, K. M. and T .B. N. Thi(2006), “Does Contagion Effect Exist Between Stock Markets of Thailand and Chinese Economic Area (CEA) during the “Asian Flu?” Asian Journal of Management and Humanity Sciences, Vol. 1, No. 1, pp. 16-36, 2006

11. 聶建中、高友笙、楊超翔(2011)，次級房貸危機前後美股對亞股的不對稱性蔓延效果，中原企管評論，第9卷第1期，頁25-52。

2. 王冠閔、吳書慧(2006)，台灣股、匯市與美國股市傳導機制之實證分析，運籌研究集刊 ，第10期，頁1-15。