Analysis Of Complex Network Structure And Systemic Risk Contribution Of Stock Market Under Stock Index Extreme Volatility

With the development of global economic integration,the relationship between financial markets in different countries becomes more and more close,which also provides the conditions for the rapid propagation of the financial crisis.As the connectivity between the various ele-ments of the financial system connection,it is thought to be associated with the stability of the financial system,the world dedicated to study how to effectively resolve the loss which the financial crisis brought,and the complex network theory is the effective way to deal with the financial system risk.Through the analysis of complex networks,if we can block the transfer of risk among financial entities,we can minimize the financial risks and losses caused by them.This paper select the financial crisis(around 2008)and the stock market volatility(around 2015)which were extreme fluctuations period,using minimum spanning tree modeling method established MST network about Shanghai Shenzhen Japan and the United States stock market.To observe the China stock market minimum spanning tree network structure evolution,nodes individual behavior,and the relationship between the stock industry before,during and after the stock index extreme volatility.Findings:In securities market the industry has a strong clustering and inter industry has homogeneity.Four securities market's MST network graph is shrinking in the stock index sharp fluctuations,and it gradually expand after the sharp fluctuations in the stock index.Shanghai and Shenzhen stock market is sensitive to the global financial crisis,has a certain ability to predict.Before the volatility of stock index,network structure of the two markets has changed significantly,to release warning signal.During stock index volatility and after the fluctuations,the material industry and information technology industry rise abruptly and occupie an important position.In particular,the material industry and(real estate)financial companies are closely linked,suggesting that stock price volatility correlation enhancementthe under the influence of uncertain factors.Combine the stock network model with the regression analysis model,established the dynamic panel of network topology index and systemic risk contribution.Findings:In the stock correlation network,stock node degree,closeness centrality and strength etc.network topology index and system Risk Spillover values showed a significant negative correlation.