This thesis examines the impact of company announcements on the daily stock returns of lowly capitalised companies. A total of 105 companies comprise the sample and 1464 events are examined over the period 21110/97 to 03/0412000. The methodology employed is primarily, empirical in nature. Event studies are conducted to gauge the impact of company announcements on stock returns using the single index market model (SIMM) as the chosen equilibrium market model for modelling abnormal returns. The study professes three mam contributions to knowledge. The empirical evidence suggests that financial announcement have a more timely impact on stock returns than non-financial announcements. Secondly, there appears to be significant over-reaction and mean-reversion exhibited by lowly capitalised firms. Thirdly, the speed of adjustment of stock prices to new information is increased in cases where shareholder concentration is high while over-reactions appear inversely proportionate to shareholder concentration. This may be a consequence of smaller firms experiencing leakage of boardroom level information prior to public announcement days.

Yes / This study examines the extent to which the change from UK GAAP to IFRS has affected companies listed on the Alternative Investment Market (AIM) in the UK. The results suggest that, on average, profit reported under IFRS is higher than that reported under UK GAAP; however, the difference is much smaller for AIM listed companies as compared to what existing literature suggests for firms listed on main stock markets. The Gray's partial analysis results indicate that despite the extensive programmes for improving convergence over time there is still a considerable discrepancy between IFRS and UK GAAP.