As an example, Morningstar's methodology calculates the weighted average ESG scores of all individual holdings in a portfolio. Based on data from sustainability researcher Sustainalytics, these scores reflect company policies and performance in areas such as carbon footprint, gender diversity, and independence of company directors, to name a few. The individual holding scores, corrected for any history of controversial company behavior, become the basis for a portfolio's sustainability score. The higher the ESG scores of the companies in an investment portfolio, the higher the portfolio's sustainability score. The investment fund is then compared with its peer group of funds from the same Morningstar category and given a ranking within this group of high, above average, average, below average, or low. Clearly, sustainability ratings for investment funds bring some important benefits to the market. They increase transparency and facilitate fund comparisons.