Concentrated Announcements on Clustered Data: An Event Study on Biotechnology Stocks
分析2000年春季三个事件（克林顿和布莱尔的政治声明、Celera Genomics的突破公告）对生物技术股票的影响，发现股票可按对政治和科学事件的反应聚类，且不同集群的无形资产市场价值影响不同。
In spring 2000, three events—two political statements by Bill Clinton and Tony Blair and a breakthrough announcement by Celera Genomics—had a major impact on biotechnology stocks. We analyze their effects over a comprehensive set of biopharmaceutical companies, using a composite return-generating model with an industry-specific patent-based factor. Our results show that stocks can be clustered according to their responsiveness to political and scientific events. Furthermore, we emphasize different impacts on the market value of intangible assets for each cluster, suggesting that growth options are valued with different criteria for therapeutics, and technology-based subsectors.