Long Haiming, Zhang Ji, Tang Nengyu
College of Finance and Statistics, Hunan University, Changsha, China.
Lally School of Management, Rensselaer Polytechnic Institute, New York, United States of America.
PLoS One. 2017 Jul 6;12(7):e0180382. doi: 10.1371/journal.pone.0180382. eCollection 2017.
This study considers the effect of an industry's network topology on its systemic risk contribution to the stock market using data from the CSI 300 two-tier industry indices from the Chinese stock market. We first measure industry's conditional-value-at-risk (CoVaR) and the systemic risk contribution (ΔCoVaR) using the fitted time-varying t-copula function. The network of the stock industry is established based on dynamic conditional correlations with the minimum spanning tree. Then, we investigate the connection characteristics and topology of the network. Finally, we utilize seemingly unrelated regression estimation (SUR) of panel data to analyze the relationship between network topology of the stock industry and the industry's systemic risk contribution. The results show that the systemic risk contribution of small-scale industries such as real estate, food and beverage, software services, and durable goods and clothing, is higher than that of large-scale industries, such as banking, insurance and energy. Industries with large betweenness centrality, closeness centrality, and clustering coefficient and small node occupancy layer are associated with greater systemic risk contribution. In addition, further analysis using a threshold model confirms that the results are robust.
本研究利用中国股票市场沪深300二级行业指数的数据,考察了一个行业的网络拓扑结构对其对股票市场系统性风险贡献的影响。我们首先使用拟合的时变t- copula函数来衡量行业的条件风险价值(CoVaR)和系统性风险贡献(ΔCoVaR)。基于与最小生成树的动态条件相关性建立股票行业网络。然后,我们研究网络的连接特征和拓扑结构。最后,我们利用面板数据的看似不相关回归估计(SUR)来分析股票行业的网络拓扑结构与行业系统性风险贡献之间的关系。结果表明,房地产、食品饮料、软件服务以及耐用品和服装等小规模行业的系统性风险贡献高于银行、保险和能源等大规模行业。具有较大中介中心性、接近中心性和聚类系数且节点占用层数较小的行业与更大的系统性风险贡献相关。此外,使用阈值模型的进一步分析证实了结果的稳健性。