Updated August 17, 2026. Quick answer: the fair value estimate is one analyst’s discounted-cash-flow answer to “what is this business worth?” — and Morningstar itself warns it is highly sensitive to the assumptions behind it. On its own it is not a buy or sell signal. The uncertainty rating is what turns it into one, by setting how large a discount is required first: a Low-uncertainty stock is a buy below 95% of fair value, an Extreme-uncertainty stock only at 50%. Use them as a pair or not at all.
What the fair value estimate is
Morningstar’s definition is short and worth reading exactly:
It represents a Morningstar analyst’s estimate of what a stock is worth.
The method is stated too, and it is a single model rather than a blend of screens:
Each stock’s fair value is estimated by using a proprietary discounted cash flow model, or DCF.
A discounted cash flow model takes a forecast of the cash a business will throw off, and discounts it back to today at a rate reflecting how risky that cash is. Which means the output is only ever as good as the forecast going in — a point Morningstar makes itself, in the same paragraph, rather than leaving to critics:
Fair value estimates are highly sensitive to Morningstar’s projections of future cash flows and other assumptions.
That sentence is the most useful one on the whole page. A fair value estimate is a considered opinion with a number attached, not a measurement.
The uncertainty rating is the other half
If the estimate is sensitive to assumptions, the obvious question is how much room for error to demand before acting on it. That is exactly what the uncertainty rating is for:
The recommended margin of safety—the discount to fair value demanded before Morningstar would recommend buying or selling a stock—widens as the uncertainty of the fair value estimate increases.
It runs on a five-level scale:
The Morningstar Uncertainty Rating operates on a scale of Low, Medium, High, Very High, and Extreme.
And Morningstar publishes the two ends of the resulting margin of safety explicitly:
a stock with an Uncertainty Rating of Low is considered a “buy” when its price drops below 95% of its fair value estimate
For a stock with an Uncertainty Rating of Extreme, its price would have to be 50% of its fair value estimate for an analyst to recommend buying it.
| Uncertainty rating | Price at which Morningstar would call it a buy |
|---|---|
| Low | Below 95% of the fair value estimate |
| Medium | Not published on the definition page read for this page |
| High | Not published on the definition page read for this page |
| Very High | Not published on the definition page read for this page |
| Extreme | 50% of the fair value estimate |
An honest gap, marked rather than filled. Morningstar’s own definition gives the required discount only for Low and Extreme. The three levels in between are real ratings with real thresholds, but those thresholds are not stated in the source read for this page, and no figure has been invented for them here. If you see a site publishing exact percentages for Medium, High and Very High, ask where they came from.
Why the number alone is not a signal
Consider two stocks, each trading at 80% of its fair value estimate — a worked illustration, not a Morningstar figure. On the fair value number alone they look identical. They are not: if the first is Low uncertainty it cleared the 95% threshold long ago, while if the second is Extreme it is still a long way from the 50% Morningstar would want. Same discount, opposite conclusions — and the difference is invisible unless you read both ratings.
This is also why a fair value estimate quoted on its own, in a headline or a screenshot, carries almost no information.
How this drives the star rating
The stock star rating is not a separate opinion — it is this comparison, expressed as an icon. Morningstar describes the star rating as a measure of a stock’s current price relative to the analyst’s estimate of what the shares are worth, where:
Those stocks trading at large discounts to their fair values receive the highest ratings (4 or 5 stars).
A 3-star rating means the current stock price is fairly close to the analyst’s fair value estimate.
So a five-star stock is a statement about price versus estimated value, filtered through the required margin of safety. It is not a statement that the company is excellent, and it is a completely different construction from the fund star rating — which is where most of the confusion in this whole system lives. That is covered on stock stars versus fund stars.
The company-quality judgement, separately, is the economic moat rating.
Sources
- Morningstar, “Fair Value Estimate”, Investing Terms and Definitions. Source document. Read 2026-08-17.
- Morningstar, “Uncertainty Rating”, Investing Terms and Definitions. Source document. Read 2026-08-17.
- Morningstar, “Morningstar Rating for Stocks”, Investing Terms and Definitions. Source document. Read 2026-08-17.
Every figure and quotation on this page was taken from the documents above, each fetched and read on 2026-08-17. Where those documents do not answer a question, this page says so rather than filling the gap.
See a stock’s current fair value estimate
Morningstar Investor shows the fair value estimate, the uncertainty rating and the star rating together, which is the only way any of the three means anything.
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