This thesis examines underpricing in Sweden using unique data on the 185 firms going public through initial public offerings (IPOs) and listing on the Stockholm Stock Exchange between 1994-2011. The average initial return in the Swedish IPO market adjusted for index movements is 11.49% but underpricing of individual IPOs was as high as 241.04%. Further, time trends in underpricing, the level of average initial returns effect on IPO supply underpricing and differences between sectors, segments and investment banks are examined. Finally, it is argued that investors must be rewarded for taking the high risk associated with IPO investing and that the average initial return of 11.49% is a reasonable compensation for that risk.