为探究新冠疫情对中国股票市场的影响,利用格兰杰因果检测,构建疫情爆发前、爆发期和疫情常态化控制三个阶段的复杂网络模型。分别从网络拓扑结构、抗毁性能和节点重要性进行比较分析。发现疫情冲击明显改变了上证行业板块结构关系,行业指数间联动效应有所减弱;网络攻击仿真实验显示,面对破坏性更强的蓄意攻击,第三阶段抵抗能力更持久,其次是第一、二阶段的网络。疫情前后行业股票重要性排序发生了显著变化,电子、社会服务、综合和商贸零售行业在股市上逐渐处于中心主导位置;计算机、家用电器和通信行业成为股市网络中信息传输效率的重要控制节点。疫情过程中,医药生物所受正向冲击明显,成为了市场中风险传染的缓冲器。
In order to explore the impact of the Covid-19 epidemic on China's stock market, the Granger causality test is used to construct a complex network model of three stages before the outbreak, the outbreak period and the normalized control of the epidemic. The comparative analysis is made from the network topology, survivability and node importance. It is found that the impact of the epidemic has significantly changed the structural relationship of the Shanghai Stock Exchange industry sectors, and the linkage effect between industry indices has weakened; the network attack simulation experiment shows that in the face of more destructive deliberate attacks, the third stage has a more durable resistance, followed by the first, second-stage network. Before and after the epidemic, the ranking of the importance of industry stocks has changed significantly. The electronics, social services, comprehensive and commercial retail industries have gradually taken an important position in the stock market; the computer, household appliances and communication industries have become important control nodes for information transmission efficiency in the stock market network. During the attack of the epidemic, the positive impact of medical biology was obvious, and it became a buffer for risk contagion in the market.
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