ROIC and the Graham Number, Explained

Short answer: ROIC (return on invested capital) measures how efficiently a business turns the money invested in it into profit — it’s the clearest quantitative sign of a durable advantage. The Graham Number is a classic formula that estimates a rough price ceiling — the most a defensive investor should pay — for conservative, asset-heavy stocks. ROIC tells you if the business is good; the Graham Number offers one cross-check on whether the price is fair — but only for the right kind of company.

These are two different tools for two different jobs, and using each in the right place is the whole skill.

ROIC — how good is the business?

Return on invested capital answers a simple question: for every dollar put into this business, how many cents of profit does it produce? A company earning 20 cents on the dollar (20% ROIC) is far better at compounding wealth than one earning 5 cents — as long as it can keep reinvesting at those rates.

The Market Lens formula

ROIC = Net Income ÷ (Total Equity + Total Debt)

This is a simplified ROIC. The textbook version divides NOPAT — operating profit after tax, or EBIT × (1 − tax rate) — by invested capital, and often subtracts excess cash from the denominator. Market Lens deliberately does not subtract cash: for cash-rich companies, removing a huge cash pile shrinks the denominator and can inflate ROIC into a misleading 100%+ figure. Leaving cash in gives a more conservative number. (Market Lens uses total shareholders’ equity directly when available; see the methodology page.)

A worked example

Suppose a company reports $600 million of net income, $2,000 million of total equity, and $1,000 million of total debt. The Market Lens ROIC is:

ROIC = $600M ÷ ($2,000M + $1,000M) = $600M ÷ $3,000M = 20%

Twenty cents of profit for every dollar of capital put to work — a strong result. Now watch what subtracting cash would do. If the company also holds $1,500 million in cash and you stripped it out of the denominator the “textbook” way:

ROIC (cash removed) = $600M ÷ ($3,000M − $1,500M) = $600M ÷ $1,500M = 40%

The number doubles to 40% without the business doing anything differently — purely an artifact of a big cash pile. That’s exactly the inflation Market Lens avoids by leaving cash in. The 20% figure is the conservative, honest read. See the formal definition in the ROIC glossary entry.

Why ROIC matters so much

ROIC is the single best number for spotting an economic moat. Here’s the logic: in a competitive market, high returns attract rivals who compete them away. So if a company earns high ROIC year after year, something must be protecting it — a brand, a network effect, switching costs, or a cost advantage. Sustained high ROIC is the financial fingerprint of a moat.

That’s why ROIC sits right next to the Moat pillar of the Buffett criteria in a Market Lens report — shown as its own quality check, though the Moat score itself is built from margins, return on equity, revenue growth, and company size rather than ROIC. A quick way to read it:

• Consistently above ~15% — a strong sign of a quality business with an advantage.
• Around the cost of capital (~8–10%) — the business is treading water; it’s not creating much value.
• Below its cost of capital — the company is destroying value even if it reports a “profit.”

The word to stress again is consistently. One good year can be luck. A decade of high ROIC is a moat.

The Graham Number — is the price fair (for the right stock)?

Benjamin Graham — Buffett’s teacher and the father of value investing — devised a formula for a rough fair-value ceiling on a conservative, asset-heavy stock:

Graham Number = √(22.5 × Earnings per share × Book value per share)

The 22.5 comes from Graham’s rule that a defensive stock shouldn’t trade above 15× earnings and 1.5× book value (15 × 1.5 = 22.5). The result is a maximum price a cautious investor might pay. If a stock trades below its Graham Number, that’s one small point in favor of it being reasonably priced.

A short worked example

Suppose a company reports $4.00 earnings per share and $25.00 book value per share:

Graham Number = √(22.5 × 4 × 25) = √2,250 ≈ $47.43

So Graham’s method suggests a defensive investor shouldn’t pay much more than about $47 a share for this business. It’s a price ceiling for a sanity check, not a precise valuation — and it can’t be calculated at all when earnings or book value is zero or negative.

The critical catch: when the Graham Number lies

The Graham Number was built in an era of industrial, asset-heavy companies, and it leans on book value — the accounting value of a company’s tangible assets. That’s the trap. For modern businesses whose value lives in brands, software, patents, networks, and research — things that barely show up in book value — the formula produces nonsense.

For that reason, Market Lens deliberately excludes the Graham Number for four sectors where it’s misleading:

• Technology
• Communication Services
• Healthcare
• Consumer Cyclical

Applying it to an asset-light software or consumer-brand company would make a perfectly reasonable business look wildly “overpriced,” because its real assets don’t appear on the balance sheet. The Graham Number belongs to defensive, asset-heavy businesses — think industrials, banks, consumer staples, and similar — not to the companies whose worth is intangible. (Utilities are not on the exclusion list, so Market Lens does apply it to them; just remember that regulated, capital-heavy balance sheets can make book value look different from economic value.)

How the two tools work together

ROIC and the Graham Number sit at different stages of the process:

1. ROIC comes first — it’s a quality measure. Use it to judge whether the business is good and whether it has a moat.
2. The Graham Number comes later — it’s one price check, used only for the right kind of stock. In Market Lens it’s averaged with a growth-adjusted fair-P/E value to form the intrinsic estimate behind the margin-of-safety score; the P/E ratio and a separate discounted cash flow estimate give you other angles.

Neither is a verdict on its own. ROIC without a fair price means you’ve found a great business you might overpay for. A low Graham Number on a company with terrible ROIC means you’ve found a cheap bad business — a value trap. You need both halves: a good business and a fair price with a margin of safety.

How to read them side by side

	ROIC	Graham Number
What it measures	Business quality — profit per dollar of capital	A rough price ceiling for the defensive investor
When in the process	First — judge if the business is good	Later — one check on whether price is fair
Formula	Net Income ÷ (Total Equity + Total Debt)	√(22.5 × EPS × BVPS)
Rough “good” signal	Consistently above ~15%	Stock trading below its Graham Number
Where it breaks	A single lucky year; ignore it, watch the trend	Asset-light firms — excluded for 4 sectors
Role in Market Lens	Separate quality metric (not a Moat input)	Averaged with fair-P/E for the margin-of-safety score

Common mistakes with ROIC and the Graham Number

• Judging ROIC off a single year. One good year can be luck or a one-time gain. A moat shows up as sustained high ROIC across many years — read the trend, not the snapshot.
• Subtracting cash to get a bigger ROIC. As the worked example showed, stripping out cash can double the number without the business improving. Market Lens leaves cash in on purpose for a more conservative read.
• Applying the Graham Number to tech, communications, healthcare, or consumer-cyclical names. The formula leans on book value, so it makes asset-light businesses look wildly overpriced. Market Lens excludes those four sectors for exactly this reason.
• Treating the Graham Number as a target price or a floor. It’s a rough ceiling — the most a cautious investor might pay — not a prediction of where the stock will trade.
• Mistaking a cheap price for a good business. A low Graham Number on a company with weak ROIC is a value trap. You need quality and a fair price, never one without the other.

Frequently asked questions

How does Market Lens calculate ROIC?

Market Lens uses a simplified formula: Net Income ÷ (Total Equity + Total Debt). It deliberately does not subtract cash from the denominator, because for cash-rich companies that would shrink the base and inflate ROIC into a misleading figure. Leaving cash in gives a more conservative number. See the ROIC definition for more.

What is a good ROIC?

As a rough guide, ROIC consistently above ~15% signals a quality business with a likely advantage; around the cost of capital (~8–10%) means the business is treading water; and below its cost of capital means it is destroying value even while reporting a profit. The key word is consistently — one year proves nothing.

What is the Graham Number formula?

Graham Number = √(22.5 × earnings per share × book value per share). The 22.5 comes from Benjamin Graham’s rule that a defensive stock shouldn’t trade above 15× earnings and 1.5× book value (15 × 1.5 = 22.5). It estimates a rough price ceiling and can’t be computed when earnings or book value is zero or negative.

Why does Market Lens skip the Graham Number for some stocks?

Because the formula relies on book value, which barely captures the worth of asset-light businesses built on brands, software, patents, and networks. Market Lens excludes it for Technology, Communication Services, Healthcare, and Consumer Cyclical companies, where applying it would give a misleadingly low ceiling. Utilities are not excluded. You can see every company’s quality and price checks together in the Stock Analyzer.

Putting it together

Use ROIC to judge quality — sustained high returns are the fingerprint of a moat — and the Graham Number as a narrow price check for defensive, asset-heavy stocks only, never for tech, communications, healthcare, or consumer-cyclical names. Right tool, right job.

See the exact formulas and the sector-exclusion rule on the methodology page, check any company’s ROIC in the Stock Analyzer, or learn how these fit the full workflow in how to find undervalued stocks.

Market Lens is educational research, not investment advice. Every figure is an estimate from public data that may be delayed or incomplete.