The Clustering of IPO Gross Spreads: International Evidence
发现IPO总价差的聚类现象不仅存在于美国，也出现在全球许多市场，但聚类不一定意味着合谋；聚类程度与总价差水平负相关，且很少有聚类包含异常正盈余。
Patterns of clustering in IPO gross spreads can be identified not only in the U.S., but also in many other markets across the world. The evidence indicates, however, that these clustering patterns are not necessarily collusive. Clustering is widespread in many countries with low gross spreads. In fact, the amount of clustering observed is negatively related to the gross spread level of a country. Additionally, an analysis of abnormal gross spreads following Hansen (2001) indicates that few clusters contain abnormal positive surpluses.