The aim with this thesis is to investigate whether increased capital flows to ESG screened indexes create higher price-to-earnings (P/E) ratios and momentum in the included stocks during the chosen time period of three years, from 2018 to 2020. The thesis will evaluate the capital flows to ESG indexes and compare both performance and P/E ratios between those and their corresponding Mother indexes. The study will also look at the development of capital flows, performance and P/E ratios separately in the four chosen geographical indexes; Global, Europe, US and Emerging Markets. The theoretical framework goes through four relevant subjects for this study; passive investing, ESG, momentum and the P/E ratio. The study has shown that the capital flows in all four ESG indexes increased during the chosen time period. Moreover, it could be proven that three out of four ESG indexes outperformed their Mother indexes, namely, Global, Europe and Emerging Markets. In the U.S. the Mother index outperformed the ESG index. Three out of four geographical indexes also had a higher increase in the average P/E ratio than their mother indexes. Here, the Global market stood out as the one that had a lower increase in P/E ratio than its Mother index. Lastly, regression analyses were made to see the relationship between the variables capital flows, average P/E ratios in the indexes and the performance of the indexes. The study showed significantly that capital flows is the explanatory variable for the increased P/E ratios on the European ESG index. However, for the other indexes no significant correlation could be proved. This led to an interesting discussion and conclusion, and also left us with a question mark. What is the reason behind this result on the European market, and why was it not possible to see any significant correlation on the other markets? Further research in this field is needed and some ideas are discussed in the last chapter of the thesis.