Background: Research shows that there are incompatible outcomes for companies who have completed an Initial Public Offering, which entails difficulties in ascertaining what acompany's financial performance will look like after the Initial Public Offering. Purpose: The purpose of the study is to investigate whether an Initial Public Offering resultsin an improvement or a deterioration in companies' financial performance in connection with a stock exchange listing on the Stockholm Stock Exchange. Furthermore, the study's sub-question aims to examine whether the financial performance differs based on the size ofthe company, in connection with an Initial Public Offering.  Theory: This study is based on three theories; Window Dressing Theory, Agency CostTheory and Window Of Opportunity.  Method: The study has applied a quantitative method in combination with a deductive approach. Two financial ratios have been applied to examine the financial performance, which are; profit growth and return on equity.  Conclusion: The empirical result shows that an Initial Public Offering leads to a deterioration in profit growth for the entire sample, before in relation to after the listing. Furthermore, the size of the company turns out to have no effect on how the financial performance is affected in relation to an Initial Public Offering.