This thesis investigates the relationship between the total expense ratio and the 5-year performance to last month for sustainable mutual funds registered in Sweden and the United States. The increasing amount of mutual funds and the shift towards sustainability in the society gives cause to study the relationship between the total expense ratio and the performance of sustainable mutual funds rather than conventional mutual funds. The analysis was conducted by testing the relationships through different regression models for both the Swedish and the U.S. market. A simple regression model was conducted for both markets to study the relation that the total expense ratio has to the 5-year performance to last month. To further analyse the relation between the two variables, a multiple regression model was conducted for both markets to further analyse the significant relationship between the total expense ratio and the 5-year performance to last month. The data was collected via Eikon and included mutual funds registered in Sweden and the U.S., each mutual fund collected was retrieved together with an ESG score which was the definitive factor whether the mutual fund could be considered as sustainable or not. The results gathered from the simple regression model for the Swedish market was found to have no significant relationship and the explanatory degree for the regression model was very low. The results regarding the simple regression model for the U.S. market are however found to be significant but with a low degree of explanation as well. Hence the result from this study indicates that there is no significant relationship between the total expense ratio and the 5-year performance to last month for the Swedish market when conducting a simple regression model, while the U.S. market has a low significant relationship between the variables. However, a multiple regression model for the Swedish market containing additional control variables presents a significant relationship between the total expense ratio and the 5-year performance to last month. The same results were found for the U.S. market when conducting a multiple regression model. The results for the Swedish simple regression model align with previous studies conducted within this area, where previous studies have found there to be no significant relationship between the total expense ratio and the performance of mutual funds, hence same results are applicable to sustainable mutual funds. However, this study did in fact also display significant relationships for the multiple regression model for the Swedish market as well as for both regression models for the U.S. market. Which indicates that the total expense ratio to some extents have an explanatory relationship between the total expense ratio and the 5-year performance to last month for sustainable mutual funds in both the Swedish market and the U.S. market.

Background: The Swedish fund savings have developed strongly over the past two decades. Together with this development, the knowledge that the earth's population is facing an extensive climate challenge has also increased. For many people today, living sustainably has become a central aspect of everyday life, and when it comes to investing their savings, the majority of Sweden's fund savers state that sustainability is something that is taken into account when choosing an investment. Investments in funds that based on measuring tools, show a high degree of sustainability have thus increased. This raises the question of whether these sustainable funds can generate a higher alpha and thus a better risk-adjusted return than the less sustainable alternatives available on the market. Previous studies have shown differences of opinion, which means that it is relevant to examine how these different types of funds perform against each other in the Swedish market.   Purpose: The aim of this study is to analyze whether fund savers that are investing in sustainable funds can generate a higher alpha and thereby a better risk adjusted return than fund savers that invests in less sustainable alternatives.   Methodology: The study was conducted with a quantitative method and a deductive approach. Sustainability ratings have been collected for 253 funds from a measuring institute. For these 253 funds, data in the form of net asset value have been collected between the period 2016 - 2020 monthly. These funds have then been evaluated based on risk-adjusted returns where regression analysis has been the groundwork for finding answers to whether alpha has been achieved compared to the market or not. Results obtained have then been statistically examined through various tests.   Conclusion: After completed study, there were no signs that studied sustainable funds have given rise to a better risk-adjusted return than the less sustainable alternatives available on the market. Of the 253 funds included in the study, only five funds showed a risk-adjusted return statistically different from zero, where three had a negative return and two a positive return. When the 253 funds were divided into four different quartiles based on sustainability ratings, it appeared that the funds with a positive risk-adjusted return were placed in quartile four, which was the one with the highest sustainability rating. However, this may be based on chance and a result of two in a sample of 253 gives clear indications that efficiency prevails in the market.