Sunday, April 06, 2008

Morningstar's New Fair Value Uncertainty Rating

At Morningstar, we try to look at the future in a probabilistic way. Practically, that means we spend a lot of time thinking about the range of possible outcomes for the companies that we cover, even though the fair values we publish are, of necessity, point estimates. For example, we use scenario analysis and other tools to estimate a variety of fair values given different combinations of plausible future events.

To better reflect this aspect of our research process, we're replacing our business risk rating with a fair value uncertainty rating. Going forward, we'll rate every stock we cover as having low, medium, high, very high, or extreme uncertainty. In assigning the rating, we'll be asking ourselves, "How tightly can we bound the fair value of this company? With what level of confidence can we estimate its future cash flows?" If you have a background in statistics, you'll recognize that what we'll be doing is estimating the size of a confidence interval for the values of the companies we analyze.

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