政策因素会长期影响股市波动吗?——基于GARCH-MIDAS模型的分析

Do Policy Factors Affect Stock Market Volatility in Long-term?--Analysis Based on GARCH-MIDAS Model

基于GARCH-MIDAS模型实证检验了政策强度对股市波动长期成分的影响。研究发现:股票资金供应政策、市场法律法规、市场监管能降低股市波动长期成分。股票资金供应政策的影响随时间推移下降较快,市场法律法规、市场监管对市场波动的影响较为持久。税收政策调整会增加股市波动长期成分,且其影响是持久的。股票供应政策和货币政策的调整对于股市波动长期成分影响不显著。样本外预测结果表明,GARCH-MIDAS模型中加入政策变量能有效提升模型预测精度。

Based on GARCH-MIDAS model,this paper empirically tests the influence of policy intensity on the long-term component of stock market volatility.The conclusions are as follows:stock capital supply policy,market laws,and market regulation can reduce the long-term component of stock market volatility.The influence of the stock capital supply policy decreases steeply over time,while the influences of market laws and market regulation are relatively lasting.Tax policy adjustment promotes the long-term component of stock market volatility,and such an impact is lasting.The influences of stock supply policy and monetary policy adjustment are not significant.The out-of-sample prediction analysis shows that adding the policy variables to GARCH-MIDAS model can effectively improve the prediction accuracy of the model.