How can different share classes of the same fund have different star ratings?
Because the Morningstar Rating uses load-adjusted returns in its calculation, the different ratings could be due to differences in loads and expenses between the share classes. However it is also likely that the different ratings are linked to the inception dates of each share class. There is an overall star rating, and star ratings for three time periods, 3, 5, and 10-year. The overall star rating is calculated using the 3, 5, and 10-year ratings. Let’s say the Acme Fund has two share classes, an A share and an F share. Acme Fund A was incepted more than 11 years ago but Acme Fund F was incepted four years ago. The 3-year star rating for both funds is 3 stars. Since the F shares do not have 5 and 10 year star ratings, 3 stars is the overall star rating. But since the A shares have a 5 star rating for both the 5 and 10-year periods, its overall star rating is bumped up to 5 stars. We put more weight on the 10 and 5 year ratings compared to the 3 year (50%, 30%, 20% is the weight for th
