The relationship between quantity traded and transaction costs has been one of the main focuses among financial scholars and practitioners. The purpose of this thesis is to investigate the informational relationship between these variables. Following insights and results of Milgrom (1981), Feldman (2004), and Feldman and Winer (2004), we use New York Stock Exchange (NYSE) data and kernel estimation methods to construct the distribution of one variable conditional on the other. We then study the information in these conditional distributions: the extent to which they are ordered by first order stochastic dominance (FOSD) and by monotone likelihood ratio property (MLRP). We find that transaction size and effective spread are statistically significantly orrelated. FOSD, a necessary condition for a "separating signaling equilibrium", holds under certain conditions. We start from two-subsample case. We choose a cut-off point in transaction size and categorize the observations with transaction sizes smaller than the cut-off point into group "low". The remaining data is classified as "high". We repeat this procedure for all possible transaction size cut-off points. It turns out that FOSD holds nowhere. However, once we eliminate transactions at the quote midpoint, the "crossings" between exchange members not specialists, FOSD holds for all the cut-off points fewer than 15800 shares. MLRP, a necessary and sufficient condition for the separating equilibrium to hold point by point of the conditional density functions, does not hold but might not be ruled out considering the error in the estimates. We also find that large trades are not necessarily associated with large spread. Instead, it is more likely that larger trades are transacted at the quote midpoint (again, the non-specialist "crossings") than smaller trades. Our results confirm the findings of Barclay and Warner (1993) regarding the informativeness of medium-size transactions: we identify informational relationships between mid-size transactions and spreads but not for trades at the quote midpoint and large-size transactions. That is, we identify two regimes, an informational one and a non-informational/liquidity one.

With the gradual expansion of China's economy, the demand for innovation and growth of China’s companies is increasing. Traditional internal research and development (R&D) and iterative product and service development are no longer sufficient to meet the fierce market competition. More and more companies are seeking breakthrough growth of overall technology, brand, and service. Therefore, mergers & acquisitions (M&A) have become a common business activity for China’s companies. The motivation of company’s M&A is complex, and as M&A laws in China and worldwide become more complicated, how to make rational and rapid M&A that can achieve strategic upgrading of enterprises has become a research issue of concern for Chinese economic, financial, accounting, and legal disciplines, etc. As a basic industry, Chinese pharmaceutical industry has not yet taken a dominant position in the world. Due to the intertwining of multiple disciplines and complex background information, the impact of M&A transaction size on the innovation performance of pharmaceutical companies has yet to be studied.Focusing on the two hot spots: M&A and innovation, in the context of China's economic transformation and upgrading, this dissertation explores the impact of M&A on innovation based on the current situation analysis and theoretical analysis, and deeply studies and reveals the mechanism and effect of M&A transaction size on company innovation. 281 M&A data of 58 listed companies in China's healthcare industry from 2008 to 2017 was collected and regression analysis was performed to examine the impact of M&A transaction size on the innovation level of companies in terms of two aspects: the number of patent applications and the number of patents granted, and on three levels: invention patents, utility model patents and design patents. The results of the research show that: M&A transaction size promotes the growth of the number of patent applications and patents granted and has a significant positive effect on enterprise innovation; and M&A transaction size has contributed to the increase of the number of utility model patent applications and patents granted. In general, the innovation performance of M&A transaction size in utility model patents is better than that in invention patents with higher technological elements. Further mechanism examination results show that the innovation performance of a company after a bigger M&A transaction is influenced by its absorptive capacity: the stronger its absorptive capacity, the more opportunities it has to absorb and transform the technologies and knowledge of an acquired enterprise into its own. Through learning and imitation, it realizes the transformation and innovation of the technologies obtained through M&A, ultimately enhancing its innovation capability. / Business Administration/Finance