Key Valuation Ratios

P/E Ratio — the most widely used valuation metric

The Price-to-Earnings (P/E) ratio is the most quoted valuation metric in investing. It tells you how much investors are willing to pay for each dollar of earnings.

A P/E of 20x means investors are paying $20 for every $1 of annual earnings. The S&P 500's long-run average P/E is approximately 15–20x. Growth stocks (fast-growing tech) often trade at 40–80x; value stocks (slow-growing industrials, banks) often trade at 8–14x.

Context is everything. A 30x P/E for a company growing earnings 40%/year is potentially cheap. A 30x P/E for a company with flat earnings is expensive. Always compare P/E to earnings growth rate (the PEG ratio: P/E ÷ Growth Rate — PEG below 1.0 is generally attractive).

P/B Ratio — asset-based valuation

The Price-to-Book (P/B) ratio compares market price to accounting book value per share.

P/B is most useful for capital-heavy businesses: banks, insurance companies, real estate, and industrials where assets are a primary driver of value. For asset-light businesses (software, consumer brands), P/B is less meaningful — a great software company might have minimal book value but enormous earning power.

P/S Ratio — for pre-profit companies

Price-to-Sales (P/S) compares market cap to annual revenue. Used when a company isn't yet profitable — common for early-stage tech, biotech, or fast-growing SaaS.

A P/S of 10x means investors are paying $10 for every $1 of annual revenue. This sounds expensive — and it is, unless the company has a credible path to high margins. A SaaS company at 10x P/S might be reasonable if it has 70% gross margins and is growing 50%/year. A retail company at 3x P/S with 5% gross margins is almost certainly overvalued.

EV/EBITDA — the professional's choice

Enterprise Value to EBITDA is the ratio most commonly used by investment bankers, private equity, and institutional analysts for comparing companies across different capital structures.

EV/EBITDA solves two problems with P/E: (1) it uses enterprise value (includes debt), so you can compare leveraged and unleveraged companies fairly; (2) EBITDA strips out non-cash depreciation charges and tax differences. A software company and a manufacturing company with similar EBITDA but different debt structures can be directly compared.

Typical EV/EBITDA ranges: Tech/software: 15–30x. Consumer staples: 10–15x. Utilities: 8–12x. A company trading at 8x EV/EBITDA in a sector where peers average 14x is potentially undervalued — assuming the discount isn't for a good reason.

ROE — return on equity

Return on Equity (ROE) measures how efficiently a company uses shareholder capital to generate profit.

A 20% ROE means the company generates $0.20 of profit for every $1 of equity. The S&P 500 average ROE is approximately 15–17%. Companies like Apple (ROE 170%+, boosted by buybacks), Visa (50%+), and Coca-Cola (40%+) are elite ROE generators. Warren Buffett specifically looks for companies with consistent 15%+ ROE without excessive debt.

ROA — return on assets

Return on Assets measures how efficiently a company uses its entire asset base to generate profit — regardless of how those assets are financed.

ROA is useful because it removes the leverage distortion from ROE. A company with 15% ROE and 25% D/E ratio vs. one with 15% ROE and 200% D/E ratio have very different risk profiles — ROA separates them. Target 5%+ ROA as a quality filter for most industries.

ROIC — the best measure of business quality

Return on Invested Capital is considered the gold standard quality metric by sophisticated investors.

ROIC answers the most important capital allocation question: does the business earn returns above its cost of capital? If ROIC > WACC (cost of capital), the company is creating economic value. If ROIC < WACC, it's destroying value even while reporting positive earnings. Companies that sustain high ROIC (15%+) over a decade are exceptional compounders.

The three rules for using ratios correctly

Real-world example: Ford vs. Tesla in 2022

In early 2022, Ford Motor traded at approximately 5x P/E and Tesla traded at over 100x P/E. Superficially, Ford looked 20x cheaper. But ratios without context are misleading.

The income statement comparison told the rest of the story: Ford's operating margin was approximately 3–4%. Tesla's was approximately 17%. Ford was growing revenue at low single digits. Tesla was growing revenue over 50% year-over-year. Ford's ROIC was in low single digits. Tesla's was expanding rapidly toward 20%+.

The 100x P/E for Tesla wasn't the market being irrational — it reflected a massive premium for a company with Tesla's growth rate, margins, and ROIC trajectory. Ford at 5x P/E wasn't automatically cheap — it reflected a low-margin, slow-growth, capital-intensive legacy business.

By late 2022, as interest rates rose and growth expectations compressed, Tesla's valuation multiple contracted significantly — the stock fell 65% from its peak even as the business continued performing well. This illustrates the risk of paying a high multiple: if growth disappoints or discount rates rise, the valuation multiple contracts sharply.