Valuation Ratios

P/E and P/B answer different questions about the same stock: P/E prices earnings, P/B prices net assets. A stock can look cheap on one measure and expensive on the other, which is why the exam tests both together.

What Is the P/E Ratio?

The P/E ratio is the most widely used valuation metric.

• Formula: P/E Ratio = Market Price Per Share / Earnings Per Share (EPS)
• Shows how much investors are willing to pay per dollar of earnings
• A P/E of 20 means investors pay $20 for every $1 of current earnings

Think of it this way: P/E is the price tag on a company's earnings. A P/E of 20 means investors are paying $20 for every $1 of profit the company earns. The higher the P/E, the more investors are betting on future growth.

Interpreting P/E:

• High P/E: Investors expect strong future growth, or the stock is overvalued
• Low P/E: The stock may be undervalued, or the company has declining prospects
• A high P/E is not automatically "bad" and a low P/E is not automatically "good"
• Growth companies (tech, biotech) typically carry higher P/E ratios than value companies (utilities, banks)

Two Types of P/E:

• Trailing P/E: Uses actual earnings from the past 12 months (backward-looking)
• Forward P/E: Uses analyst estimates of future earnings (forward-looking)

How to use P/E effectively:

• Compare to the company's own historical P/E: is it trading above or below its typical range?
• Compare to industry averages: a P/E of 30 is normal in tech but unusual in utilities
• Compare to the overall market: the S&P 500 historical average is roughly 15-20x

Exam Tip: Gotchas

• A low P/E does not automatically mean "buy." It could mean the company is in trouble (declining earnings expected). Similarly, a high P/E could mean strong growth ahead, not overvaluation. Context is everything.
• P/E uses earnings per share in the denominator. P/B uses book value per share. These are often confused.

What Is the P/B Ratio?

The P/B ratio compares what the market says a company is worth versus what the accounting books say.

• Formula: P/B Ratio = Market Price Per Share / Book Value Per Share
• Book value = total assets minus total liabilities (shareholders' equity), divided by shares outstanding
• Compares market valuation to accounting value

Think of it this way: Book value is the accounting value left for shareholders after subtracting total liabilities from total assets, not necessarily what the company would fetch if it sold everything off. P/B tells you whether the market thinks the company is worth more or less than that accounting value.

Interpreting P/B:

• P/B < 1.0: Stock trades below book value; may be undervalued (or the assets are impaired)
• P/B > 1.0: Market values the company above its net asset value, reflecting intangibles, brand, or growth
• P/B = 1.0: Market price equals accounting book value

When P/B is most useful:

• Capital-intensive industries: Banking, insurance, manufacturing, real estate, where tangible assets dominate the balance sheet
• Less useful for: Tech companies, service firms, and other asset-light businesses where value comes from intellectual property, brand, or human capital (these have large intangible values not captured in book value)

Exam Tip: Gotchas

• P/B < 1.0 does not automatically mean "undervalued." It could also mean the company's assets are overstated or impaired.
• P/B is most relevant for asset-heavy industries (banks, manufacturing), not tech companies. Asset-light companies have intangible value that book value does not capture.

What's the Golden Rule of Ratio Analysis?

Both P/E and P/B follow the same rule as all financial ratios:

• Never use a ratio in isolation
• Always compare to industry peers, competitors, and historical trends
• A "high" or "low" ratio only has meaning relative to a benchmark
• Use multiple ratios together for a complete picture; one ratio can mislead, but several pointing the same direction build a stronger case

Exam Tip: Gotchas

• All valuation ratios require comparison to peers and history. A ratio alone tells you nothing about whether a stock is a good investment.

What Should You Check on Exam Day?

• Can you state both formulas: P/E = market price per share / EPS, and P/B = market price per share / book value per share?
• Do you know a low P/E is not automatically a buy signal, and a high P/E is not automatically overvaluation?
• Can you distinguish trailing P/E (past 12 months) from forward P/E (analyst estimates)?
• Do you know P/B below 1.0 means the stock trades below book value, which can mean undervalued or mean the assets are impaired?
• Can you identify that P/B is most useful for capital-intensive industries like banking and manufacturing, and less useful for asset-light businesses like tech?
• Do you remember that no valuation ratio means anything without comparison to peers, competitors, and historical trends?