AbstractThe University of Manchester Haojun ChenDoctor of Business Administration (DBA) Three Essays in Financial Market Predictability 16 September 2016Prior studies have shown that returns exhibit certain predictable patterns that are inconsistent with the mainstream finance theory. In this thesis, I explore the behaviour of returns following three different types of market events with a particular focus on behavioural and non-behavioural factors that are attributable to the predictability of post-event returns. This thesis consists of three self-contained empirical essays. The first essay examines the information role of large S&P500 futures trades (commercial, noncommercial, dealers, asset managers, and hedge funds) in shaping future index returns. I find that commercial firms' net trading level appears positively correlated with future index returns but the relationship is not stable across time. Based on more recent data, hedge funds appear superior in terms of access to information and/or trading ability but this advantage is only preserved at high frequency. Therefore, the current weekly Commitment of Traders (COT) report - published with a three-day delay - prevents timely public access to this type of information. Also, trading signals based on two of the more popular position-based sentiment indicators do not produce significant average returns. Overall, this calls into question the reliability of COT-based trading signals used by market professionals. The second essay studies the impacts of short sellers' trading in shaping the behaviour of stock returns following extreme price moves using data from stock market in mainland China where short sales were initially prohibited. Extreme price moves occurring under non-prohibitive/prohibitive short-sale constraints are defined as shortable/non-shortable events. I find shortable events exhibit less post-event price drift/reversals than non-shortable ones, indicating an increase in the efficiency of stock prices reacting to unexpected events. Further analysis of short sellers' trading activities on the price event days suggests that they are successful in trading informed price shocks but not in trading uninformed ones. Finally, I find evidence of massive short-covering that amplifies price shocks. The third essay investigates investors' reaction to stock market rumours using data from China where listed companies are required to clarify rumours appearing in the media. I find that post-clarification abnormal returns exhibit continuation of pre-clarification momentum for rumours that are not denied by the listed companies and reversals for those which are denied. These results suggest that investors are unable to distinguish the reliable rumours from the false ones, as they under-react to rumours containing material information and over-react to those without. Further regression analyses on post-clarification abnormal returns using various subsamples of rumour events show that investors respond more efficiently to rumours when they are more informed about news topics or the rumoured companies.