What ratios cannot tell you

Imagine a company with a perfect set of ratios. Its return on capital is high and rising. Its margins are fat. Its cash conversion is clean, its balance sheet lightly leveraged, its valuation reasonable for the growth. Every number this part has taught you to compute comes out beautifully. And yet this company could be a fraud whose accounts are invented, a former leader whose customers are quietly defecting to a cheaper rival, a maker of a product a new technology is about to render obsolete, or a two-decade success story resting entirely on a founder who retires next year. The ratios would look identical in every one of those cases — and identical to a genuinely excellent business. illustrative

This is the module that puts a boundary around everything the part has built. Ratios are powerful, and this part has spent nine modules learning to read them honestly — as questions, against their context, cleaned of cosmetics. But every ratio shares one built-in limitation: it is computed from the reported past. So the things that decide a company's future, and that live outside the reported numbers, are invisible to all of them. Four of those things matter most: the integrity of the numbers (are they even real?), the competitive position (is the moat widening or eroding?), the technology risk (is the whole business about to be disrupted?), and the succession question (does the quality survive the people who built it?). This final module of the part is about those four blind spots — why no ratio can see them, and where you have to look instead. It is the bridge out of the ratios and into the parts that examine exactly what the ratios cannot.

A ratio is a backward-looking quantification. It takes numbers a company has already reported and expresses a relationship between them. That is its strength — it is precise, comparable, and grounded in the actual accounts — and it is also the exact source of its four great blind spots. Whatever is not in the reported numbers, or not yet in them, a ratio cannot capture. This module exists because the most dangerous mistake a numerate analyst can make is to believe that a complete ratio analysis is a complete analysis. It is not; it is half of one, and the missing half is often where the money is won or lost.

The four blind spots each fail the ratios for the same underlying reason. Integrity is invisible because ratios are computed from the reported numbers, so they cannot sit in judgement on whether those numbers are honest — a fabricated set of accounts yields flawless ratios, and the ratio has no way to audit its own inputs. Competitive position is invisible because ratios lag it: a firm losing its moat can hold its margins for years by declining to cut price, so the margin looks healthy right up until the collapse, while the leading signal — slipping market share, defecting customers — sits outside the accounts. Technology risk is invisible because it lives entirely in the future: a business about to be disrupted shows perfect current numbers until the disruption lands, because the threat has not yet touched the reported figures. And succession is invisible because ratios record what a business achieved, not who or what system achieved it, so a superb record built on one irreplaceable founder looks identical to one built on a durable institution. This module exists to mark these four limits clearly, so that a strong ratio set is read as necessary but never sufficient — and to hand off to the parts built precisely to examine what the ratios cannot: forensics for integrity, competition and foresight for the moat and the technology, and management for succession.

Four blind spots, each invisible for a specific reason, each with a place to look instead.

Integrity: the ratios cannot audit their own inputs. This is the deepest blind spot, because it undermines everything else. Every number in this part — ROCE, margin, cash conversion, leverage — is calculated from the reported accounts, so if the accounts are false, the ratios are precisely, elegantly false too. A well-constructed fraud produces a beautiful ratio profile, because that is often the whole point of the fraud. No amount of ratio analysis can detect this, because the ratios are downstream of the very numbers in doubt. You check integrity by a different method entirely — tracing profit to cash, reading the auditor and the related-party notes, watching for the tells of manipulation — which is the subject of the forensics part. A ratio can never tell you whether to trust the number it is built from.

Competitive position: margins lag the moat. A ratio can show that a firm is profitable; it is slow to show that a firm is becoming less defensible. When a cheaper or better rival starts taking share, the incumbent can often protect its margins for years simply by not responding on price — so the margin ratio stays healthy while the moat quietly erodes underneath it, until the day the firm is finally forced to cut price and the margin falls hard and late. The leading indicators of competitive decline — market share slipping, customers defecting, pricing power weakening, distribution being lost — sit outside the accounts, in the market. Ratios confirm strength after the fact; they do not warn of its loss in advance.

Technology risk: the threat is in the future. A business about to be made obsolete by a new technology shows flawless numbers until the obsolescence arrives, because a threat that has not yet reduced sales or margins is simply not in the reported figures. Ratios are computed from what has happened; a disruption is, by definition, what has not happened yet. Assessing it means looking forward — at the substitute technology, at what rivals and new entrants are building, at whether the product's usefulness is durable — which no backward-looking number can do. The strongest current ratios offer no protection against, and no warning of, the next technology.

Succession: ratios record results, not their source. A superb long-term record is a fact about the past; whether it will continue is a fact about people and systems that the ratios do not capture. A twenty-year run of high returns built on one founder's judgement, capital allocation and relationships looks identical, in ratio form, to one built on a deep, institutionalised organisation — yet one survives the founder's departure and the other may not. The ratios cannot tell you how dependent the record is on individuals, how deep the management bench is, or whether the culture that produced the numbers outlasts the people who created it. That is a judgement about management and organisation, and it is the subject of the management part.

The four blind spots are universal, but each one bites hardest in particular sectors — and knowing where each risk concentrates tells you which non-ratio question to weigh most heavily for a given business.

The thread closes the whole part. The generic ratios, the sector-specific hero metrics, the cleaning of cosmetics — all of it is the discipline of reading the reported numbers well, and it is indispensable. But this final module marks its edge: even a flawless ratio analysis is silent on whether the numbers are true, whether the moat is holding, whether a technology is about to sweep the business away, and whether the quality survives its people. Each of those is a leading, decisive question, and each is answered by looking outside the ratios — at the forensic tells, the market share, the technology roadmap, the management bench. This is why the parts that follow exist and why they come after the ratios rather than before: you learn to read the numbers thoroughly first, precisely so you understand exactly what they cannot tell you, and turn to the right tools for the rest. A strong ratio set earns a company the right to the next four questions; it never answers them.

A composite firm arrives with the most attractive ratio profile in its sector: ROCE in the thirties, twenty years of compounding earnings, clean cash conversion, negligible debt, a valuation that looks fair for the growth. On the numbers alone, it is close to a perfect business. Run the four questions the ratios cannot answer, and see how much of the case they have not touched. illustrative

First, integrity: are the numbers real? The ratios cannot say — they are built from the reported figures — so this is checked elsewhere, by tracing the twenty years of profit to twenty years of cash (does operating cash flow track earnings?), by reading the auditor's history and any related-party dealings, by watching for the tells of the cosmetics module. Suppose that check passes cleanly; the ratios did not earn that reassurance, the forensics did. Second, competitive position: is the moat holding? Here the ratios actively mislead if trusted alone — the fat margin is a lagging signal, so you go to the market and find that a well-funded rival has been taking share in the firm's core segment for three years, and the margin is intact only because the incumbent has not yet had to respond on price. That is a leading warning the ROCE cannot show, and it materially dents the case. Third, technology risk: could the product be displaced? The firm's core offering depends on a standard that a newer approach is beginning to erode; the current numbers are pristine, but the roadmap question is live, and it sits entirely outside the accounts. Fourth, succession: the twenty-year record was built by a founder-CEO now past sixty, with no obvious successor and a thin bench — so the very consistency the ratios celebrate may be the fingerprint of one irreplaceable person.

Put it together and the "close to perfect business" on the ratios is, on the four questions the ratios cannot answer, a company with honest accounts (good), an eroding competitive position (concerning), a live technology threat (concerning), and serious founder dependence (concerning). The ratios were necessary — they earned the company a serious look — but they were nowhere near sufficient, and three of the four decisive risks were invisible to every number in this part. The habit this whole part has been building culminates in a piece of humility: read the ratios thoroughly, extract everything they can honestly tell you, and then deliberately turn to the four things they cannot — because that is usually where the outcome is actually decided.

This module is itself about what ratios cannot tell you, so the honest limit here is the reverse one: the four blind spots are not a checklist that, once ticked, makes you safe. Integrity, competitive position, technology and succession are judgements, not calculations, and each can be got wrong even by someone who knows to ask it. Confirming that the accounts trace to cash reduces the integrity risk but does not eliminate it; judging that a moat is holding is a fallible read of a moving competitive picture; assessing a technology threat is genuinely hard and often wrong; evaluating succession is guesswork about the future. Knowing where to look is not the same as seeing clearly once you look there, and this module hands you the questions, not the answers.

Nor are these four the only things outside the ratios. Regulation can reshape an industry, macroeconomic and cycle forces can overwhelm any single company's numbers, and plain luck plays a larger role than any framework admits. The four blind spots are the ones that most often hide behind a strong ratio set and most often decide the outcome, which is why they earn their own parts later — but "what ratios cannot tell you" is a larger territory than four items, and treating the four as exhaustive would repeat, one level up, the very error this module warns against: mistaking a good framework for a complete one.

And there is a final, load-bearing limit that runs through the whole part. Even a perfect analysis — flawless ratios and sound judgements on all four blind spots — cannot tell you what price the market will pay, or when, or why it so often moves opposite to the fundamentals on the day the results come out. A company can be excellent on every dimension this part and the next few examine and still be a poor investment because it was bought at the wrong price, or a frustrating holding because the market prices expectations rather than results. That gap — between understanding a business and understanding its price — is the one no amount of company analysis closes, and it is the subject the later part on why the price moves the other way is built to address.

How it comes up. When the numbers are flawless, a thoughtful analyst stops asking about them and starts asking the four things the numbers cannot show. The question sounds like this: "The financials are excellent, so I want to ask about what they don't capture — how is market share trending in your core segment, what's your read on the newer technology some entrants are pushing, and what does the succession plan look like beyond the founder?" The analyst has finished with the ratios and moved to the blind spots.

A good answer, verbatim-style.

"Right questions. Share in the core segment slipped about two points last year to a newer competitor — we're responding with a lower-priced line, which will cost some margin. On technology, we take the substitute seriously and have a team working on it; I won't pretend it's not a risk. On succession, we've brought in a deputy CEO who's run the largest division for five years, and we're deliberately institutionalising decisions that used to sit with the founder. None of that is in the numbers, but it's what we spend our time on."

That answer engages exactly what the ratios miss — it concedes share loss, takes the technology threat seriously, and shows a real succession plan — rather than pointing back at the strong financials.

An evasive answer, verbatim-style.

"Our track record speaks for itself — twenty years of industry-leading returns and rock-solid financials. We're confident that the same disciplined approach that delivered those results will continue to serve us well. We don't see any of these as material concerns given our proven model."

Notice the move. Asked about the four things the ratios cannot show, it answers by pointing back at the ratios — "track record," "returns," "financials" — and dismisses the forward risks by invoking the past. Using a strong history to wave away integrity, competition, technology and succession questions is precisely the substitution this module warns against.

The follow-up nobody asks, and what its absence means. "Set the financials aside — walk us through share trend, the technology roadmap versus the substitute, and the specific succession plan and bench." That forces the conversation off the numbers and onto the blind spots. If the room lets "the track record speaks for itself" answer questions about the future, either those forward risks are real and management prefers the comfort of the history, or the analysts have been lulled by the ratios into not pressing. A management that answers every question about the future by reciting its past ratios is relying on exactly the limitation this part closes on: that a strong number set is not an answer to the questions the numbers cannot reach.

1. Believing a ratio can validate its own inputs. Ratios are computed from the reported numbers, so they cannot tell you whether those numbers are honest. A fraud produces beautiful ratios; integrity is checked by forensics, not by the ratios.

2. Reading a healthy margin as a healthy moat. Margins lag competitive position — a firm losing share can hold its margin for years, then lose it suddenly. The leading signal is market share and pricing power, which sit outside the accounts.

3. Trusting strong current numbers against technology risk. A business about to be disrupted shows perfect ratios until the disruption lands, because the threat is in the future. Assess it from the roadmap and the substitutes, not the current numbers.

4. Mistaking a great record for a durable institution. Ratios record results, not who produced them, so a founder-dependent record looks identical to an institutionalised one. Succession risk is invisible to every ratio.

5. Treating a complete ratio analysis as a complete analysis. The ratios are necessary and never sufficient; three or four of the decisive risks routinely sit entirely outside them. A strong ratio set earns a company the next questions, it does not answer them.

6. Forgetting that price is the final blind spot. Even a perfect analysis of the business cannot tell you what the market will pay or when it will move against the fundamentals. Understanding the company is not the same as understanding its price.