We use a test for co-explosiveness to improve our understanding of the effects of green finance on the valuation of stocks. First, by testing against temporary explosiveness in the MVIS Global Coal Index, the NASDAQ OMX Green Economy Index, and the MSCI World Equity Index, we find evidence for explosive periods in the latter two time series. Second, we use a recently proposed econometric procedure to test for co-explosivity of the jointly explosive variables, i.e., the NASDAQ OMX Green Economy Index and the MSCI World Equity Index. The test results indicate co-explosive behavior. The MVIS Global Coal Index, on the other hand, shows completely different time series properties. Assuming that there is no speculative bubble, the theory of corporate finance suggests that this empirical finding should be a result of differences with regard to risk premia demanded by investors buying the respective stocks and (respectively or) expected future corporate earnings of the firms examined here. More specifically, the existence of higher risk premia and pessimistic expectations regarding future corporate earnings should suggest that investors are looking at the business models of firms that are included in the MVIS Global Coal Index with at least a certain degree of skepticism. Thus, our results imply that not adhering to the principles of green finance perhaps might be more important for the stock market valuation of firms than adhering to it.

我们使用共爆测试来提高我们对绿色金融对股票估值影响的理解。首先，通过测试 MVIS 全球煤炭指数、纳斯达克 OMX 绿色经济指数和 MSCI 世界股票指数的暂时爆发性，我们发现后两个时间序列存在爆发期的证据。其次，我们使用最近提出的计量经济学程序来测试联合爆炸变量的协同爆炸性，即纳斯达克 OMX 绿色经济指数和 MSCI 世界股票指数。测试结果表明存在共爆行为。另一方面，MVIS 全球煤炭指数显示出完全不同的时间序列属性。假设没有投机泡沫，公司金融理论表明，这一实证发现应该是投资者购买相应股票所要求的风险溢价和（分别或）此处研究的公司预期未来公司收益的差异的结果。更具体地说，较高风险溢价的存在和对未来企业盈利的悲观预期表明，投资者正在以至少一定程度的怀疑态度看待 MVIS 全球煤炭指数中包含的公司的商业模式。因此，我们的结果表明，对于公司的股票市场估值而言，不遵守绿色金融原则可能比遵守绿色金融原则更重要。更具体地说，较高风险溢价的存在和对未来企业盈利的悲观预期表明，投资者正在以至少一定程度的怀疑态度看待 MVIS 全球煤炭指数中包含的公司的商业模式。因此，我们的结果表明，对于公司的股票市场估值而言，不遵守绿色金融原则可能比遵守绿色金融原则更重要。更具体地说，较高风险溢价的存在和对未来企业盈利的悲观预期表明，投资者正在以至少一定程度的怀疑态度看待 MVIS 全球煤炭指数中包含的公司的商业模式。因此，我们的结果表明，对于公司的股票市场估值而言，不遵守绿色金融原则可能比遵守绿色金融原则更重要。