I examine the determinants of cross-sectional liquidity in the IPO aftermarket during the period of 1995 through 2005. I find that past price performance, the extent of stock visibility, the mass of informed agents, and certain IPO attributes play a role in explaining IPO trading activity. My empirical evidence shows that differences of opinion and estimation uncertainty about an IPO firm affect little IPO liquidity. My findings contribute to the understanding of determinants of IPO aftermarket trading. I also investigate whether contemporaneous overreaction tends to occur following persistent information in the options market. More specifically, I compare the reactions between growth and value investors, and small and large investors conditional on past price reactions. My empirical results suggest that value investors react more strongly than growth investors following a series of prior information shocks, as measured by the cumulative level of overreaction. Small investors tend to react more strongly than large investors conditional on prior information shock, as measured by the cumulative sign or level of overreaction. The results imply that overreaction is a function of investor types and previous information and contribute to the overreaction hypothesis in the options market.

Cette thèse a pour objet d’analyser l’impact du suivi par les analystes financiers lors de l’introduction en bourse sur la qualité du marché secondaire et sur la future vie boursière de l’entreprise. Dans cet objectif, trois études empiriques sont menées sur le marché français. La première apporte une nouvelle explication à la relation positive qui existe entre la sous-évaluation initiale et la liquidité sur le marché secondaire. Elle montre que cette relation positive se forme par le biais de la couverture des analystes financiers. En se basant sur la méthode de l’analyse de survie, notre deuxième étude révèle que le suivi par les analystes financiers a un impact positif sur la durée de vie boursière de l’entreprise. La troisième étude démontre que la couverture peut également influencer l’occurrence et la rapidité d’occurrence d’une émission secondaire. Il apparaît que les firmes les plus couvertes au moment de l’introduction sont celles qui retournent le plus rapidement au marché pour effectuer une émission secondaire garantie. Ces travaux soulignent l’importance du suivi par les analystes financiers des introductions en bourse. / This thesis aims to analyze the impact of IPO analyst coverage on the quality of the secondary market and on the future market life of the firm. For this purpose, three empirical studies are conducted on the French market. The first one provides a new explanation for the positive relation between initial underpricing and post-listing liquidity. We find that this positive relation is formed through analyst coverage. Our second study shows that analyst coverage has a significant positive impact on IPOs survival. The third study explores the linkage between analyst coverage and subsequent seasoned equity offerings. Our results indicate that analyst coverage is a significant predictor of subsequent SEO and that more covered firms are those that return more quickly for an insured offering. Our findings enlighten the importance of analyst coverage around IPOs.