Updated for the 2026-2027 CFA® Level I curriculum.
Comparable company valuation estimates a stock's value by comparing its price multiples to those of similar firms. Analysts use this method because it is fast, market-based, and easy to explain to clients.
On the CFA Level I exam, you need to calculate and interpret four multiples: P/E, P/OCF, P/S, and P/B, and use them to judge whether a stock looks cheap or expensive relative to its peers.
Quick Answer
Comparable company valuation applies a peer group's average or median price multiple to a target company's own per-share fundamental.
The four required multiples are
P/E (price to earnings)
P/OCF (price to operating cash flow)
P/S (price to sales)
and P/B (price to book value).
Each divides current share price by a different per-share measure. A multiple above the peer average suggests the market prices the stock higher relative to that fundamental, but this is not automatically good or bad. Context on growth, risk, and quality drives the interpretation.
Key Takeaways About Comparable Company Valuation Using P/E, P/OCF, P/S, and P/B
Peer group selection requires firms with similar business models, industry exposure, growth, and risk profiles.
P/E divides price per share by earnings per share (EPS) and is the most widely used multiple, but it breaks down when earnings are negative or volatile.
P/OCF divides price per share by operating cash flow per share and avoids some accrual accounting distortions found in earnings.
P/S divides price per share by sales per share and works even when a company has no profit, since sales are rarely negative.
P/B divides price per share by book value per share and is useful for asset-heavy or financial firms.
The method of comparables applies a benchmark multiple (peer average or median) to the target's own fundamental to estimate an implied value.
A multiple that differs from the peer group does not automatically mean overvalued or undervalued. Differences in growth, margins, and risk must be considered.
What You Need to Know for CFA Level I
Identify what makes companies reasonably comparable for peer-group valuation.
Calculate P/E from price per share and EPS, and explain what a high or low P/E implies.
Calculate P/OCF and P/S, and explain when each is preferred over P/E.
Calculate P/B and connect it to a company's balance sheet strength.
Apply the method of comparables to estimate an implied share price from a peer multiple.
Recognize when multiples are not directly comparable due to inconsistent numerators or denominators.
Peer-Group Selection Logic
A peer group is a set of companies similar enough to the subject company that comparing their multiples is meaningful. Analysts typically look for firms in the same industry, with similar business models, similar growth expectations, and similar capital structures.
Comparing a mature utility to a fast-growing technology firm produces misleading multiples even if both operate in the same broad sector. A high P/E for the growth firm may reflect expected earnings growth, not overpricing. A low P/E for the utility may reflect stability, not a bargain.
For Level I, you do not need to build a formal peer screen. You need to recognize when a comparison is reasonable and when it is not, and explain why differences in growth, margin, or risk affect multiple levels.
Calculation and Interpretation of P/E
Price to earnings (P/E) is calculated as:
A P/E of means investors pay $18 for each $1 of current earnings. A higher P/E can reflect expected earnings growth, lower perceived risk, or market optimism. A lower P/E can reflect slower growth, higher risk, or a temporarily depressed stock price.
P/E has two common versions. Trailing P/E uses EPS from the last twelve months. Forward P/E uses a forecast of next year's EPS. Mixing the two when comparing companies creates an inconsistent comparison, since forward P/E is typically lower than trailing P/E for a growing company.
P/E is unreliable when EPS is negative or unusually volatile, since the ratio becomes meaningless or highly distorted.
Calculation and Interpretation of P/OCF and P/S
Price to operating cash flow (P/OCF) is calculated as:
Operating cash flow reflects actual cash generated by core operations. It is harder to manipulate through accounting choices than net income, since it excludes many non-cash accruals. Analysts often prefer P/OCF over P/E when earnings quality is in question or when companies use different depreciation or inventory methods.
Price to sales (P/S) is calculated as:
Sales are rarely negative, so P/S works for companies with negative earnings or negative cash flow, including many early-stage firms. P/S does not account for cost structure, so two companies with identical P/S ratios can have very different profitability and very different intrinsic value.
Calculation and Interpretation of P/B
Price to book value (P/B) is calculated as:
Book value per share equals total shareholders' equity divided by shares outstanding. It represents the accounting net worth of the firm on a per-share basis.
A P/B above 1.0 means the market values the firm above its accounting net worth, often because of expected future growth or intangible value not fully reflected on the balance sheet. A P/B below 1.0 can signal undervaluation, but it can also signal that the market expects asset write-downs or weak future returns. P/B is especially useful for banks, insurers, and other firms where balance sheet assets closely reflect market value.
Using Comparable Multiples to Estimate Value
The method of comparables converts a peer multiple into an implied value for the target company. The general form is:
If the peer average is and target EPS is , the implied price is . Compare this estimate with the market price while considering differences in risk and growth.
Multiple | Numerator | Denominator | What It Measures |
|---|---|---|---|
P/E | Price per share | Earnings per share | Price paid per dollar of current earnings |
P/OCF | Price per share | Operating cash flow per share | Price paid per dollar of operating cash flow |
P/S | Price per share | Sales per share | Price paid per dollar of revenue |
P/B | Price per share | Book value per share | Price paid per dollar of accounting net worth |
Worked Example
An analyst is valuing Marlow Components, a mid-size auto parts supplier, using comparable company analysis. She selects three peer firms with similar size, product lines, and growth rates.
Peer group data:
Company | P/S |
|---|---|
Peer A | |
Peer B | |
Peer C | |
Average |
Marlow's sales per share is $18.00. Marlow's current market price is $50.00.
Step 1: Apply the average peer multiple to Marlow's fundamental.
Step 2: Compare implied price to current market price.
Marlow trades at $50.00, above the implied price of $45.00.
Based on the peer group's average P/S multiple, Marlow's stock appears overvalued relative to its comparables. Before acting on this conclusion, the analyst should confirm that the peer group is truly comparable to Marlow in growth rate, margin structure, and business risk. If Marlow has stronger growth prospects than its peers, some premium may be justified.
Common Exam Traps
Comparing firms that are not reasonably comparable
A low multiple on a company in a different industry or with different growth prospects does not automatically make it cheap. Check business model, growth, and risk before comparing multiples.
Mixing per-share and company-wide quantities
Total market capitalization divided by EPS is not a valid P/E. Keep the numerator and denominator on the same per-share basis, or use total equity value divided by total earnings, consistently.
Using an inconsistent denominator definition
Comparing one company's trailing P/E to another's forward P/E produces a distorted comparison. Confirm both companies use the same earnings, cash flow, or sales period.
Treating a higher or lower multiple as automatically attractive
A low P/E can reflect real risk, not a bargain. A high P/B can reflect strong expected returns, not overpricing. Multiples require context before drawing a conclusion.
Practice Question
An analyst identifies three comparable companies with an average P/S multiple of . The target company has sales per share of $18.00 and a current market price of $50.00. Based on the comparable company method, what is the implied share price, and is the target overvalued or undervalued relative to its peers?
Implied price of $45.00; target appears overvalued
Implied price of $45.00; target appears undervalued
Implied price of $50.00; target appears fairly valued
Correct Answer: A
Calculation: .
The current price of is above the peer-implied price.
Option B applies the correct implied price but reverses the direction of the conclusion. A market price above the implied value signals overvaluation, not undervaluation.
Option C assumes the implied price equals the current market price without completing the multiplication step, skipping the required calculation.
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FAQs About Comparable Company Valuation Using P/E, P/OCF, P/S, and P/B
Why use P/OCF instead of P/E?
P/OCF relies on operating cash flow, which is less affected by accounting accruals than net income. Analysts use it when they suspect earnings quality issues or when comparing firms with different depreciation or inventory methods.
Why does P/S work when a company has negative earnings?
Sales are rarely negative, even for unprofitable companies. P/S lets analysts value early-stage or currently unprofitable firms where P/E is not meaningful.
What does a P/B below 1.0 mean?
It means the market values the company below its accounting book value. This can signal undervaluation, but it can also reflect expected asset write-downs or weak future profitability. Context matters before drawing a conclusion.