Title: Profitability, capital structure and its impact on market valuation Background: Capital structure is a topic that financial research has focused a lot on and there are several theories about how companies act and should act with the mix of equity and liabilities in their financing. The continued research on the role of the capital structure and its impact on companies has found that the capital structure has a clear impact on companies' cost of capital, which affects the market valuation of companies. Purpose: The study has two sub-purposes. The first sub-objective is to study the effect of profitability on the debt-to-equity ratio. The second is to analyze the effect of the debt-to-equity ratio on the market valuation. Method: The method in the study is a cross-sectional study with a deductive approach. The hypotheses in the first sub-purpose of the study have been formulated with the help of the Tradeoff theory, the pecking order theory, and previous research. The hypotheses in the second sub-purpose of the study have been formulated with the help of the signaling of debt theory. Conclusion: The results of the study find an indication that profitability has an impact on the debt-to-equity ratio and that the pecking order theory tends to have a better explanatory effect regarding the relationship between the two. And that the loan-to-value ratio has no significant effect on the market valuation. Keywords: Capital structure, financial leverage, debt-to-equity ratio, profitability, market value, Trade-off Theory, Pecking Order Theory, Signaling of debt Theory