Background: For the past 30 years, the neoclassical finance has been questioned bybehavioural finance. The main difference is behavioural finance ́s ability to explain a behaviour that deviate from rationality. One of the major biases within behavioural finance is overconfidence. Overconfident behaviour describes an investor with too strong belief in their own ability. This bias is not well-examined within behavioural finance in Sweden. The consequences of overconfidence are the investor ́s overvaluation skills which in turn leads to unnecessary risk-taking, excessive trading and economic losses. Purpose: The purpose of this thesis is to investigate if the overconfident bias exists among Swedish private investors. A study if the demographic factors; gender, age, marital status, education, and experience effect the level of overconfident behaviour. Further, an investigation to identify industries overconfident investors prefer or despise. Method: Our study use a deductive approach with a quantitative research. From the basis of previous studies, five hypotheses explaining a relation between demographic factors and overconfidence have been formulated. The data is collected through an online survey, published in finance forums between 2020-03-10 to 2020-03-22 which gave 233 participants. A binary logistic model was performed in STATA to examine if the hypothesis should be rejected or not. Conclusion: The findings from our study show presence of overconfidence among Swedish private investors. Statistically significant results confirm that gender, age, education, and experience have an impact on overconfident behaviour. Men are more overconfident than women, younger investors act more overconfident, higher education increase overconfidence, and more experienced investors are more overconfident.