Mimicking the insider : A study in the Swedish bank sector

Abstract: Background: Achieving an abnormal return on your investment is something investors are trying to achieve. A lot of attempts have been made to try and find an investment strategy that always generates abnormal returns, although none has been proven to be absolute. Efficient Market Hypothesis (EMH) proponents argue that when it comes to public available information, one could not get an abnormal advantage of this information. Behavioural Finance (BF) proponents however argue that there may still be possible for this due to human psychology. For markets to have the best possibilities for being efficient, it must be a large and competitive market where information transfers rapidly. When analysing aspects necessary for earning abnormal return for outsiders, there are indications that these aspects does exist and it might be profitable to mimic the insiders operating in the Swedish large-cap bank sector. The large-cap bank sector contains of Svenska Handelsbanken (SHB), Nordea, Swedbank and Skandinaviska Enskilda Banken (SEB). Purpose: The purpose of this thesis is to explore whether there exist an opportunity in the Swedish bank sector for outsiders to earn abnormal return based on insiders’ transactions. In the process an indirect test will be made to see if the semi-strong form of efficiency holds for the Swedish bank sector. Method: Observing the movements on the market when the information about insider trading becomes public. The results are tested for both statistical significance and economical significance. Conclusion: The purpose of this study was to try and determine whether or not outsiders could mimic the insider’s transactions in order to earn abnormal return in the Swedish bank sector. However, based on this study this seems not to be possible in the overall sector. The signs that indicated that this would be possible for the Swedish large-cap banks turned out to be false. The result that showed statistical difference from zero was negative and it was therefore concluded that the insider did not predict the future very well. This leads to the conclusion that there are stronger factors than the sign of insiders’ transactions determine the future stock price. Since the insiders could not predict the future stock prices, any attempt from outsiders to try to exploit their information would not be beneficial. This resulted in the BF assumptions of under- and overreaction in the price did not occur in this study and instead the results turned out to be in line with the EMH description of semi-strong markets.