A DCF that spits out one exact price hasn't finished the job — it's hidden the uncertainty inside the assumptions. Here's how to drag it back out, read it like a range instead of a verdict, and use its width to size conviction.
A Zone Beats a Number
Every input in a DCF is a guess, even the well-researched ones. Sensitivity analysis stops pretending otherwise — it moves the two assumptions that matter most, together, and shows you the full range of honest answers instead of one falsely precise one.
Three concepts — work through them in order or jump to the one you need.
"You'd never tell someone you're entering a trade at exactly $47.13 and exiting at exactly $52.86 with certainty. A DCF that outputs one clean number is making the same false promise."
Think about how you'd actually answer "when will you get to the airport?" You wouldn't say 3:14 PM sharp. You'd say "between 3 and 3:30, depending on traffic" — because you already know several inputs (lights, congestion, parking) are uncertain, and a single number would just be lying about how confident you are. A DCF deserves the exact same honesty. Growth rate, margin trajectory, discount rate, terminal growth — every one of those is an estimate, even the well-researched ones. A model that reports "$126.40 fair value" to the penny isn't more precise than one that reports a range. It's just hiding the same uncertainty one decimal place deeper.
Instead of publishing one price target, IU runs the model across a bear / base / bull range, then builds a sensitivity table — a grid showing how the fair value answer changes as the two assumptions that matter most move together, typically the discount rate (WACC) and the terminal growth rate (g). The single number was never the analysis. The range always was — a point estimate just repackages it to look more certain than it is.
A support zone tells you where buyers have historically stepped in — not a single tick. A fair value range tells you where a business is worth stepping in — not a single price. Both are honest about the same thing: precision you don't actually have.
Next: how to actually build and read the two-variable grid that produces that range — and which axis moves the needle more.
Next Concept →"A trader who knows which indicator actually leads price has an edge over one reacting to all of them equally. A grid tells you which assumption actually leads your fair value — the other one is mostly noise."
A sensitivity table is just a grid — one axis is WACC, the other is the terminal growth rate (g), and each cell is the fair value that combination produces. Reading it well isn't about staring at the whole table. It's about noticing which axis moves the number more when you nudge it. That tells you exactly where the real uncertainty in the position lives, and where it doesn't.
| WACC \ g | 2.0% | 2.5% | 3.0% |
|---|---|---|---|
| 8% | $142 | $149 | $158 |
| 9% | $121 | $126 | $132 |
| 10% | $105 | $108 | $113 |
Scan down a column: moving WACC from 8% to 10% (fixing g at 2.5%) drops fair value from $149 to $108 — a swing of roughly 28%. Now scan across a row: moving g from 2.0% to 3.0% (fixing WACC at 9%) only moves fair value from $121 to $132 — about 9%. Same-sized nudge, three times the impact from one axis.
| Variable | Range Tested | Fair Value Swing |
|---|---|---|
| WACC | 8% → 10% | ≈ 28% |
| Terminal Growth (g) | 2.0% → 3.0% | ≈ 9% |
In the table above, WACC is doing three times the damage — or the favor — that terminal growth is. That's not a coincidence; discount rate compounds every year in the forecast and the terminal value, while g only affects the terminal value calculation. Whenever WACC dominates like this, that's where diligence time belongs: interrogate the cost-of-capital assumptions (covered in the CAPM & WACC guide) before spending another hour arguing over a quarter-point of terminal growth.
Just like a trader learns which timeframe or indicator actually leads price for a given setup, a sensitivity grid tells you which input is the real driver of the valuation and which one is along for the ride. Stop treating every assumption as equally risky — the grid already told you which one isn't.
Knowing how to read the grid is half the job. The other half is turning that range into an actual decision — how wide is too wide, and what does IU do about it.
Next Concept →"A tight consolidation before a breakout tells you conviction is building. A sensitivity grid that stays tight across reasonable assumptions is telling you the exact same thing about a thesis."
Once the grid exists, most people's eyes go straight to the base case in the middle and ignore everything else. That's backwards. The base case is just one cell. The width of the whole range — how far bear sits from bull across reasonable assumptions — is the more honest signal, because it's telling you how much the final answer actually depends on things you can't know for certain.
A tight range across a defensible set of assumptions — bear and bull only a modest distance apart — signals a resilient thesis: the business's value doesn't hinge on getting a handful of guesses exactly right. A wide range that swings from deeply undervalued to overvalued means the real risk in the position lives in the assumptions themselves, not in the market's pricing of them.
Bear, base, and bull cases in IU deep dives aren't arbitrary ±10% haircuts around a base number. Each is built from a distinct, named set of operating assumptions — bear might assume margin compression from pricing pressure, bull a faster-than-guided capacity ramp — so the resulting range reflects genuine business scenarios, and its width becomes a real input into position sizing, not just a disclaimer.
When current price sits below the bear case in an IU sensitivity grid, that's treated as a high-conviction setup — the market is pricing in an outcome worse than the downside scenario already accounts for. When price sits mid-range between bear and bull, that's a monitor posture: the market and the model roughly agree, and there's no mispricing edge to act on yet.
Don't ask a DCF "what's the price target?" Ask it "how wide is the honest range, and where does the current price sit inside it?" The first question invites false precision. The second one is a framework you can actually trade off of.
Sensitivity analysis and terminal growth work as a pair — go back to see exactly why that one growth assumption carries so much weight in the first place, or continue to the full Valuation & DCF guide.
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