This paper analyses the difference in risk-adjusted returns between Sin-stocks and SRI-investing for the period 2001-2021. The analysis was conducted by creating two optimally risky portfolios according to the Modern Portfolio Theory, one comprised of only Sin-stocks and one with only high ESG scoring companies. The Sin-stocks contained stocks from four different sectors, alcohol, gambling, tobacco and weapons while the companies for the SRI-portfolio was chosen from the FTSE4Good index. The regression models were chosen to follow both the CAPM, and the Fama & French three factor model and the regressions were in the end conducted with the GARCH model which showed results that both the SRI-portfolio and the Sin-portfolio had a general excess return over the market. The two portfolios were also compared with the help of Sharpe Ratio and Jensen’s Alpha. The Sharpe ratio as well as the Jensen’s Alpha showed that the Sin-portfolio had the highest risk-adjusted returns. In conclusion, the SRI-portfolio as well as the Sin-portfolio both outperformed the market during the time period 2001-2021 and they were both less volatile than the market.