This thesis is an empirical event study that examines the short-run performance of initial public offerings (IPO), known as underpricing and initial return. I argue that literature which only presents equal weights could potentially give the reader a skewed understanding of the width of the concept. By using a new data set of Nordic IPOs during the period 2009-2018, I provide estimates using equal as well as market capitalization weights consistently to give a more nuanced and fair picture. The equally weighted first-day initial return is estimated to be 4.96% and the value weighted first-day initial return is estimated to be 5.32% during the examined time period. Further, the initial return is examined in relation to firm characteristics as well as quarterly index returns and issuance volume. No statistically significant characteristics that can identify additional levels of underpricing was found. Quarterly average initial returns and quarterly index returns are independent of each other. In line with previous literature the positive relationship of issuance volume and initial return is valid on a quarterly level, indicating that firms tend to go public in times of positive and higher initial returns to a greater extent.