Do Insiders know best? : A study of reported insider trades in the Norwegian and Swedish Stock Market.

Abstract

In this thesis we investigate insider trading on Oslo and Stockholm stock market. We analyze 2515 insider trades in Norway from 21.09.2010 - 20.12.2017 and 3825 trades in Sweden from 01.01.2014 - 09.02.2017. To observe the insider effects, we applied the same event study approach as MacKinlay (1997). From this we find that cumulative abnormal returns are significantly different from zero for both countries in the short term event window. Market value was shown to have a negative effect on CAR from buy transactions in both countries and to have an insignificant (Norway) or significantly positive (Sweden) effect on CAR from sell transactions. The effect of price to book value is somewhat negative for buy transactions in the shorter term in Norway and for all event windows in Sweden. Differences in CAR that can be attributed to insider position are generally small. Our results indicate the speedier reporting in Sweden after the legislation change does not trigger any lager market reactions and thus not provide any more information value to the market. The main result of our study is that both mean and median cumulative abnormal returns are significantly higher than zero soon after the buy events and significantly lower than zero after the sell events. Overall, the conclusion is that there have been more opportunities for enjoying positive abnormal returns in Norway than in Sweden.