"Initial public offering" (IPO) means that a company's shares are made available for the first time in an official stock exchange. This study examines 61 IPOs completed on Nasdaq OMX Stockholm between the years 2000-2014. When a company is publicly traded for the first time, there could be a problem with the valuation and pricing of the shares. It’s im-portant that the information is reliable at launch since investors use this as a basis for valua-tion of the shares. A phenomenon that occurred in connection with IPOs is underpricing, meaning that companies share prices rise during the first day of trading

The purpose of this paper is to study the return of IPOs conducted on Nasdaq OMX Stock-holm. Initially the study put emphasis on the first day of trading, to investigate the preva-lence of over- or underpricing. This is to evaluate if the companies estimated value at launch was well balanced and consistent with the markets valuation. Furthermore, the study will examine the variation and correlation in long term returns. Historical stock prices for companies were obtained from Thomson Reuters Datastream to conduct a comprehensive survey on the population. The stock prices used were adjusted stock prices, meaning that prices were adjusted for, among other things, splits, dividends and share issues in order to be comparable over time. To study the stock prices over time a quantitative approach was applied to enable statistical analysis and generalizations based on the studied companies. The study intends, through repeated cross-sectional data, to examine the variation in the average yield.

The study showed that 39 of 61 companies were undervalued according to the market since they traded above their issue price when the stock market closed after the first day of trad-ing. The average underpricing of the sample was 5.98%. The result of the study also show that the timing of IPOs are of importance as well as the economic cycle impact on returns in both the short and long term.