How to Compare Two Stocks

Comparing two stocks is the step where valuation stops being an exercise and starts being a decision. It is also where most people go wrong, because the temptation is to line up one metric, find the lower number, and call it cheaper.

Comparisons only mean something when both companies are measured the same way, on the axes that actually drive returns, and with the cheapness of each judged against the quality of each.

Normalise before you compare anything

Four adjustments have to happen before a single ratio is meaningful.

• Same period. A twelve-month trailing figure against a forward estimate is not a comparison. Pick trailing or forward and use it for both.
• Same accounting framework. If one company capitalises development costs and the other expenses them, their earnings and asset bases are not directly comparable. Read the policy notes.
• Per share, not absolute. A company with twice the net income and four times the share count is smaller per share. Everything that matters to you is per share.
• Same currency and fiscal year. Both matter more than people expect, especially for companies with significant overseas revenue.

Five axes, and nothing more

A workable comparison covers five things. Adding more axes does not improve the decision; it just gives you more opportunities to rationalise the answer you wanted.

Stetron against Kestrel

Kestrel is a second fictional industrial supplier, the sort of competitor that shows up in the same screens as Stetron. Same sector, same customer base, very different economics.

A screen ranking on P/E alone puts Kestrel first. It is 3.5 multiple points cheaper, and on P/B it is dramatically cheaper -- 1.21x against 2.89x.

Now look at what you are buying with those points. Stetron earns 19.9% on equity against Kestrel's 11.0%. That difference is almost entirely margin: 7.2% against 4.5%. Both companies turn assets at roughly the same rate, and Kestrel uses less leverage, so its lower return is a genuine operating result rather than a conservative capital structure. Stetron carries 0.55x net debt against 2.40x, covers interest 9.8 times against 4.2 times, and converts 77% of net income into free cash flow against 64%. It is also growing roughly three times as fast.

The multiple you are paying for all of that is 3.5 points. Put differently, Stetron's price is 14.5 times earnings for a 20% return on equity; Kestrel's is 11 times earnings for an 11% return. Per unit of return on equity, Stetron at 0.73x P/E per point of ROE is cheaper than Kestrel at 1.00x. The screen said the opposite.

The reverse case, honestly

There is a version of this comparison where Kestrel wins, and it is worth stating because it is the argument you will hear from someone who owns it.

If Stetron's 7.2% margin is cyclical -- that is, if it is currently at a peak and the history shows a 5% average -- then the current $2.60 of earnings is inflated relative to normal. Normalise it to $1.80 and the P/E goes from 14.5x to 20.9x. Meanwhile Kestrel's 4.5% margin, if it is a trough against a 5.5% average, has normalised earnings of $2.70 and a normalised P/E of 9.0x. Suddenly the cheaper stock is the more expensive one.

This is why the first step in any comparison is to establish where each company sits in its own cycle. The CAGR calculator run over ten years rather than three will tell you whether the current margin is typical or exceptional. A three-year window starting at a cyclical low flatters every cyclical company on earth.

What comparisons cannot do

Relative valuation tells you what the market is currently paying for businesses like these. It does not tell you what either is worth. If the whole sector is priced for growth that will not arrive, comparing two members of it just tells you which of them will fall less.

The discipline is to run the relative comparison and an absolute one, then ask whether they agree. Run the reverse DCF on each: Stetron's price implies a growth rate, Kestrel's price implies a different one. If Kestrel's implied growth is 1% and you believe it will do 2%, it is genuinely cheap on its own terms, not merely cheap relative to a more expensive peer. That is a defensible conclusion. "It trades at a lower multiple" is not.

The sequence that works

1. Normalise both companies to the same period, framework and currency.
2. Decompose return on equity for each. Establish whether the return comes from the business or the balance sheet.
3. Check the balance sheet of each against a 40% earnings decline. Eliminate any that fail before you value them.
4. Compare cash conversion over a full cycle, not one year.
5. Establish where each sits in its own cycle, using a ten-year history rather than three.
6. Value each on an absolute method. Then compare what the prices imply.
7. Only then look at the multiples, and use them to test the conclusion rather than to form it.

When you have a conclusion, size it properly. A comparison that produces a 3.5-point multiple gap and a clear quality difference can still destroy capital if the position is large enough that a normal adverse move forces you to sell. The position size calculator converts a view into a number of shares against a stated risk, and the margin of safety calculator converts your valuation into a price you are willing to pay. A comparison is an input to those two decisions. It is not a substitute for them.

And the honest ending: most comparisons produce no clear answer. Two well-run businesses in the same industry, both reasonably priced, usually differ about as much as the estimates do. Recognising that and doing nothing is a legitimate outcome that costs you nothing. Forcing a choice between two adequate options is how good analysis turns into a bad position.

Frequently asked questions

How do I compare two stocks in the same industry?

Normalise first, then compare five axes and nothing more. Normalising means the same period, the same accounting treatment, per-share figures, and the same currency and fiscal year. The five axes are profitability, growth, valuation, balance sheet and cash conversion. On this site's two suppliers, the comparison looks like this: Stetron at $37.60 earns a 19.9% ROE on a 7.2% net margin and converts 77% of net income into free cash flow; Kestrel at $24.20 earns an 11.0% ROE on a 4.5% margin and converts 64%. Same industry, same customer base, materially different economics -- which is exactly what the five-axis frame is designed to expose.

Is the stock with the lower P/E the better buy?

Not automatically, and the pair used throughout this site shows why. Kestrel trades at 11.0x earnings against Stetron's 14.5x, so on that single axis Kestrel looks 24% cheaper. But Kestrel earns that multiple on an 11.0% ROE, a 2% three-year revenue CAGR and 64% cash conversion; Stetron earns its higher multiple on 19.9%, 6% and 77%. The quality gap is wider than the valuation gap, which is why the multiple differs in the first place. A lower P/E is only a bargain when the return on capital behind it is comparable.

Which ratios matter most when comparing stocks?

The balance-sheet and cash-conversion axes, because they decide who survives a downturn. Stetron carries net debt of 0.55x EBITDA with interest covered 9.8x; Kestrel runs 2.40x with cover of 4.2x. Neither is distressed, but in a 40% earnings decline Kestrel's cushion is thinner and refinancing competes with reinvestment. Cash conversion tells a similar story: 77% of Stetron's net income becomes free cash flow against 64% for Kestrel, meaning Stetron's earnings arrive as cash more reliably. Profitability gets the headlines; survivability decides the long-run outcome.

What if the comparison is too close to call?

Then the correct decision is no decision. Two well-run businesses, both reasonably priced, often differ by less than the uncertainty in the estimates that produced the comparison -- a 3.5-point multiple gap can sit comfortably inside the error bars of a five-year growth forecast. Forcing a trade in that situation converts sound analysis into an arbitrary position. Passing on a comparison that does not resolve costs nothing; the market will offer unclear pricing on hundreds of other names. This is one of the few situations in investing where doing nothing is strictly better than being wrong.

Related guides

• What Is a Good P/E Ratio? — The arithmetic of a justified multiple, and the four ways a low P/E ratio lies to you
• The Graham Number Explained — Graham's ceiling tested on two companies, and the three things it cannot see

More guides

• The DCF Method Explained — The forecast half of the model, worked end to end on one cash flow
• How to Value a Stock — The full valuation sequence on one worked example, from choosing a method to setting a buy price
• Free Cash Flow: What It Is and Why It Matters — The input every valuation depends on, including a case where profit is positive and cash flow is not
• Margin of Safety — How big a discount a given business deserves, and why a low multiple is not the same as a discount
• Dividend Investing — Testing whether a dividend is actually safe, using payout, cash coverage and leverage
• How to Read a Cash Flow Statement — The three sections, the eight sign combinations, and what each one warns you about
• Intrinsic Value vs Market Price — Why the two diverge, when cheap is not cheap, and what should force your estimate downward
• How to Read a Balance Sheet — Reading the asset side properly: six ratios, the ROE decomposition, and four common traps
• Dividend Yield vs Total Return — Four ten-year scenarios showing why a high yield and a high return are different things
• WACC Explained — The discount rate built from five sourced inputs, on the same worked example

Free valuation calculators

• DCF Calculator — fair value from five years of cash flow plus terminal value
• Dividend Discount Model — Gordon Growth valuation for dividend payers
• CAGR Calculator — compound growth rate and forward projections
• Dividend Yield Calculator — yield, income per $10,000, capital needed
• Payout Ratio Calculator — dividend safety and sustainable growth
• P/E Ratio Calculator — multiple, earnings yield, PEG, target price
• Graham Number Calculator — Graham's maximum buy price
• Total Return Calculator — price change plus dividends, annualized
• EV/EBITDA Calculator — enterprise value against operating earnings
• WACC Calculator — weighted average cost of capital for discounting
• Two-Stage DDM Calculator — high-growth then stable dividend valuation
• EPS Calculator — basic and diluted earnings per share
• P/B Ratio Calculator — price against book value, with ROE context
• Margin of Safety Calculator — discount between value and price
• Compound Interest Calculator — future value with periodic contributions
• Reverse DCF Calculator — the growth rate today's price already assumes
• DuPont ROE Calculator — break return on equity into its three drivers
• Position Size Calculator — how many shares to buy for a set risk