Investors spend considerable time analysing businesses, studying competitive positions, reading annual reports, tracking management decisions, and then hand the most consequential part of the process to a set of tools that are, at best, incomplete and, at worst, quietly misleading. Ratios like Price-to-earnings, Price-to-sales, or Discounted cash flow models anchored to a terminal value. These are the instruments of professional finance, taught in every business school, used in every investment bank, and repeated in every equity research report published every day. Their ubiquity is mistaken for reliability. It is not the same thing.

This article is about why conventional valuation methods carry significant limitations that are rarely acknowledged, what those limitations mean for the investor trying to make honest decisions, and what a more rigorous approach looks like.

The Problem with Conventional Multiples

Price-to-Sales

The price-to-sales ratio divides market capitalisation by annual revenue. It became particularly fashionable during periods of high-growth technology investing, where many businesses had no earnings to speak of and analysts needed some anchor for valuation.

The fundamental problem with price-to-sales is that it ignores everything that happens between the top line and the bottom line. Revenue is what comes in the door. What matters to the investor is what remains after paying employees, suppliers, landlords, tax authorities, and the capital expenditure required to keep the business running. A business generating $10 billion in revenue and converting 2% of it into free cash flow is a fundamentally different investment from one converting 25% of the same revenue, but a price-to-sales ratio treats them identically. The metric is indifferent to cost structure, capital intensity, and the business’s actual ability to generate cash for its owners. Using it as a primary valuation tool is the equivalent of buying a restaurant based on how many tables it has without asking whether it makes any money.

Price-to-Earnings

The price-to-earnings ratio divides the current stock price by the earnings per share over the past twelve months. It is the most widely used valuation metric in investing. It is also one of the most easily misunderstood.

A P/E ratio tells you what the market is currently paying per dollar of historical earnings. What it does not tell you is whether that price is right. When analysts compare a stock’s current P/E to its historical average, they are implicitly assuming that the historical average was a reasonable price, which assumes the market was pricing it correctly in the past, which is circular reasoning. The market is not a reliable reference point for its own rationality.

The P/E ratio also uses accounting earnings, which are subject to non-cash adjustments, depreciation schedules, and one-time items that can make the same underlying business look cheap or expensive depending entirely on accounting choices. Two businesses with identical cash generation can carry very different P/E ratios based purely on how their accountants treat certain expenses. This is a structural flaw in the metric.

Price-to-Free-Cash-Flow

Price-to-free-cash-flow is a more meaningful metric than P/E or P/S because free cash flow, operating cash flow less capital expenditure, is closer to what the business actually generates for its owners. But it carries its own distortions.

Free cash flow fluctuates significantly with capital expenditure cycles. A business that is investing heavily in new capacity, building new stores, expanding manufacturing, upgrading infrastructure, will show depressed free cash flow during the investment period even if the underlying earnings power is growing strongly. Conversely, a business that has deferred necessary investment will show elevated free cash flow in the short term while quietly eroding its competitive position. Point-in-time price-to-FCF ratios capture neither dynamic accurately. When free cash flow is distorted by these cycles, earnings per share can serve as a more stable proxy, or the analyst must normalise free cash flow to reflect the mid-cycle level rather than the current year’s figure, adjusting for both capital expenditure timing and inventory movements that can temporarily inflate or depress the reported number.

Critically, free cash flow per share must always be adjusted for stock-based compensation. SBC is a real economic cost to shareholders, it either dilutes existing ownership or requires buyback activity to offset, but it does not appear as a cash outflow in the free cash flow statement. A business that reports strong free cash flow while issuing significant equity compensation to employees is overstating its true cash generation. The adjustment is not optional; it is the difference between what the business earns and what the owners actually receive.

Conventional multiples, taken together, are useful as a rough sanity check, a way of quickly orienting to whether a business is in the general vicinity of reasonable or clearly extreme. They should never be the decision anchor. They describe the present and the past. Investment returns are determined by the future.

Fair Value is a Fiction

Beyond the specific flaws of individual multiples lies a more fundamental problem: the concept of fair value itself.

When an analyst says a business has a fair value of $X per share, they are implicitly claiming to know the sum of all future cash flows the business will generate, discounted back to today. That is a claim about everything the business will earn for the rest of its existence, decades of future performance, compressed into a single number. The precision is false. No one knows what a business will earn in fifteen years accurately. No model, however sophisticated, can reliably project the competitive dynamics, technological changes, regulatory shifts, and management decisions that will determine cash flows decades from now.

The standard tool for producing this false precision is the discounted cash flow model. A DCF model constructs a series of projected cash flows over an explicit forecast period, typically five to ten years, and then adds a terminal value representing all cash flows beyond that period in perpetuity. The terminal value typically represents 60% to 80% of the total calculated value of the business. The number that drives most of the answer is the one with the least analytical foundation, a single assumption about a growth rate that will persist forever, applied to a business operating in a world that will look nothing like today’s.

Practitioners know this. The terminal value assumption is where the model’s conclusion is engineered. An analyst who wants to justify a higher price assumption raises the terminal growth rate by half a percentage point. The model produces a higher fair value. The analysis looks rigorous because it is expressed in a spreadsheet with many rows. The subjectivity is hidden inside a single cell.

The WACC, the weighted average cost of capital used as the discount rate, carries its own problems. It is derived partly from beta, a measure of how much a stock’s price moves relative to the market. Beta is a property of the stock price, not the business. Using price volatility as an input to value the business means the discount rate is partly determined by the market’s own mood swings. On a day when the market is fearful and the stock falls 20%, the beta rises, the WACC rises, and the model produces a lower fair value, not because anything changed in the business, but because the market was nervous. This is tautology expressed in the language of finance.

The honest position is this: the value of a business is the sum of all its future discounted cash flows. That number is unknowable with precision. Any model that claims to calculate it exactly is being misleading. What can be done honestly is to estimate a range, acknowledge the assumptions explicitly, require a meaningful margin of safety between the price paid and even the conservative end of that range, and focus analytical energy on businesses whose future is sufficiently clear to make the estimation meaningful at all.

Clarity is a Pre-requisite

This last point deserves emphasis, because it connects the valuation methodology directly to the quality of the business being analysed.

A valuation is a representation of what the investor believes the business will produce in the future. The reliability of that representation depends entirely on how predictable the business’s cash flows are. A business with volatile, cyclical, or structurally uncertain earnings produces projections with enormous error bars. Even the most sophisticated framework applied to an unpredictable business produces an unreliable output, not because the framework is flawed, but because the input is noise.

This is why selectivity in business quality and rigour in valuation are not separate disciplines. They are the same discipline. Focusing analytical energy on businesses with durable competitive advantages, stable gross margins, predictable revenue streams, and a long track record of generating consistent free cash flow is not conservatism, it is the precondition for valuation to be meaningful at all. A business whose earnings fluctuate by 40% from year to year cannot be projected with confidence, which means the estimated embedded years carry so much uncertainty that the margin of safety required to invest responsibly becomes impractically large.

The framework described in the next section is only reliable when applied to businesses with sufficient clarity about their future to make the projection credible. Applied to highly cyclical, leveraged, or structurally uncertain businesses, it produces numbers that feel precise but are not. The investor must know the difference.

A More Honest Framework

Rather than asking what a business is worth, a question that implies a precision no one possesses, a more useful question is: at today’s price, how many years of future cash flows am I paying for?

The framework constructs a year-by-year series of discounted free cash flow per share projections and asks precisely this. The output is not a fair value. It is a number of embedded years, the stretch of the future that today’s price has already purchased. Everything the business earns beyond that point comes to the investor for free. The fewer the embedded years, the more of the future the investor receives without paying for it. The more embedded years, the longer the investor waits before the pre-paid portion of the future is exhausted and genuine excess returns begin to accumulate.

To make this concrete: imagine analysing a business like McDonald’s. The investor projects the next 20 years of free cash flow per share, accounting for the company’s growth opportunities, addressable market, pricing power, and share buyback behaviour, and discounts that entire stream back to today. If the current stock price reflects only the present value of the first 8 of those 20 projected years, the investor is paying for 8 years of future earnings and receiving the remaining 12 years of the projection, plus everything beyond year 20, entirely for free.

The question then becomes one of conviction about the business. McDonald’s has operated for over 70 years, serves tens of millions of customers daily across more than 100 countries, and has demonstrated through multiple economic cycles that its cash generation is durable and growing. If an investor believes with reasonable confidence that McDonald’s will continue operating and generating cash for decades beyond year 8, which its track record strongly supports, then a price embedding only 8 years of future earnings is not merely cheap. It is a bargain that can absorb meaningful errors in the underlying projections and still produce an exceptional outcome. The investor does not need to be precisely right about the growth rate in year 14 or year 19. The margin between what they paid for and what the business will likely deliver is wide enough to accommodate imprecision.

This is precisely why the number of embedded years matters more than a calculated fair value. It does not tell the investor what the business is worth, no one knows that. It tells them how much of the future they are pre-paying for, and how much they are receiving for free. The wider that gap, the more room exists for the investor to be wrong and still win.

What matters is not whether the embedded years are 14 or 16, both are in the same vicinity and call for the same investor behaviour. What matters is the difference between 12 embedded years and 35.

The Importance of the Entry Price

The practical implication of all of this is that the price paid at entry is one of the most consequential investment decisions an investor makes, more consequential, in many cases, than which business they choose.

Consider two examples from recent market history.

Apple ($AAPL). At the end of 2016, Apple’s stock price embedded approximately 10 years of future cash flows, at a moment when the market was uncertain about iPhone saturation and the company’s ability to sustain its growth. Warren Buffett initiated Berkshire Hathaway’s first Apple position in the first quarter of 2016 and continued building it aggressively. Over the following nine years, Apple’s free cash flow per share grew at a compound annual rate of approximately 11.7%. The stock price grew at approximately 27.7% annually over the same period. The share count fell by around 32% over the period through consistent buybacks, which contributed to per-share growth, but the gap between the 11.7% fundamental growth and the 27.7% price growth cannot be explained by buybacks alone. The dominant force was valuation expansion: the market re-rated Apple from 10 embedded years to over 40 embedded years as confidence in the franchise grew, and that re-rating added approximately 16 percentage points of annual return on top of what the business itself delivered. An investor who owned Apple through this period did not merely capture the fundamental growth of the business. They captured the fundamental growth plus an enormous revaluation bonus that was only available because the entry price was so compelling. Buffett has since significantly reduced Berkshire’s Apple position as the valuation entered and remained in the most stretched territory.

Alphabet ($GOOG). In early 2022, Google’s stock traded at approximately $148, embedding around 22 years of future cash flows. An investor who bought at that price and holds today at approximately $384 has generated a compound annual return of 27%. An investor who waited, and bought instead in late 2023 at $87, when the embedded years had compressed to approximately 12 and the market was deeply pessimistic about digital advertising and the competitive threat from AI-powered search, and holds today has generated a compound annual return of approximately 64%. The business is identical. The competitive position did not change materially between those two entry points. The difference in return is almost entirely a function of valuation at entry.

These are not cherry-picked anomalies. They are illustrations of a principle that operates in every market, in every cycle, for every business: the price paid at entry determines a significant portion of the return received, independent of how the underlying business performs. A great business bought at an excessive valuation can produce mediocre returns. The same great business bought at a compelling valuation can produce exceptional ones.

What This Means in Practice

Valuation is an estimation exercise that produces a range of plausible outcomes, shaped by assumptions about the future that will inevitably be imperfect. The honest investor acknowledges this and builds their process around it, requiring a margin of safety that provides room to be wrong, focusing on businesses whose futures are sufficiently clear to make the estimation meaningful, and treating the entry price as one of the few genuinely controllable variables in an otherwise uncertain process.

Conventional multiples have their place as a quick orientation tool. They are not a substitute for thinking carefully about what the current price implies about the future, whether that implication is reasonable given the evidence, and how much of the future the investor is pre-paying for before the free portion begins.

The goal is not precision. The goal is honesty about uncertainty, discipline in requiring adequate compensation for the risks taken, and the patience to wait for prices that make the investment genuinely compelling rather than merely defensible.

A Comprehensive Guide to Business Valuation