This study examines how corporate capital structure changes before, during, and after the IPO-year within the Nordic context between the years 2000 and 2020. By analyzing both external and internal factors, the study aims to understand which variables explain changes in firms' debt ratios. A longitudinal research design was adopted, and panel regression models were used to isolate these effects within the same firms over time. The results indicate that the debt ratio is highest prior to the IPO, decreases during the IPO-year, and increases again post-IPO-year, findings that align with theories such as Market Timing Theory (MTT), Trade-Off Theory (TOT), and Pecking Order Theory (POT). Industry-specific differences and market conditions also influence capital structure decisions, highlighting the contextual nature of capital structure. This study contributes to the understanding of financing strategies in relation to IPOs in the Nordic context and emphasizes the importance of both internal and external factors in explaining these structural changes.