What is the Morningstar Rating for mutual funds (a.k.a. the star rating)?
The Morningstar Rating for mutual funds, commonly called the “star rating,” brings both performance and risk together into one evaluation. Morningstar adjusts for risk by calculating a risk penalty for each fund based on “expected utility theory,” a commonly used method of economic analysis. Although the math is complex, the basic concept is relatively straightforward. It assumes that investors are more concerned about a possible poor outcome than an unexpectedly good outcome and that those investors are willing to give up a small portion of an investment’s expected return in exchange for greater certainty. A “risk penalty” is subtracted from each fund’s total return, based on the variation in its month-to-month return during the rating period, with an emphasis on downward variation. The greater the variation, the larger the penalty. If two funds have the exact same return, the one with more variation in its return is given the larger risk penalty.
