Know Thy Neighbor: Industry Clusters, Information Spillovers, and Market Efficiency
研究发现产业集群内的公司股价更有效，企业迁入集群后股价中行业信息增加，原因是地理邻近降低信息生产成本，分析师更关注集群内股票，机构投资者也倾向于持有集群内多家股票。
Firms in industry clusters have market prices that are more efficient than firms outside clusters. To establish causality, we analyze exogenous firm relocations and find that firms that relocate into industry clusters have higher levels of industry information in their prices. We argue that geographical proximity allows for information spillovers, reducing marginal cost to information producers. Our evidence supports this view: Analysts are more likely to cover stocks inside industry clusters, and when institutional investors have a large position in one stock in the industry cluster, they are more likely to hold other stocks in the same industry cluster.