What Is the Price-to-Book Ratio? P/B Explained
The price-to-book ratio (P/B) tells you how much you're paying for a company's net assets. It compares the stock's market price to its book value — the accounting net worth behind each share — and it's one of the classic ways investors gauge whether a stock looks cheap or expensive relative to what the company owns.
The formula
You can also compute it for the whole company: total market cap ÷ total shareholders' equity. Either way, the ratio answers one question: for every $1 of net assets on the books, how many dollars are investors paying?
A worked example
Say a company's shares trade at $30, and its book value per share is $15.
A P/B of 2.0 means investors are paying $2 for every $1 of the company's net assets. If instead the shares traded at $12 against that same $15 book value, the P/B would be 0.8 — the market values the company at less than its net assets on paper.
How to read the number
- P/B above 1 — the market values the company above its net assets. This is normal and usually reflects expected future profits, brand strength, or growth the books don't capture.
- P/B around 1 — the price roughly matches net asset value. Common in asset-heavy industries.
- P/B below 1 — the market values the company below its book value. This can flag a potential bargain or a business investors expect to shrink or lose money.
Why context is everything
A P/B number is meaningless without knowing the industry. Consider why:
| Company type | Typical P/B tendency | Why |
|---|---|---|
| Banks, insurers | Near 1 | Value is mostly financial assets on the books |
| Manufacturers | Low to moderate | Value tied to physical assets |
| Software, tech | High | Value is intangible — code, brand, network |
A software firm with a P/B of 10 isn't necessarily "expensive" — its real value (its product and users) barely appears on the balance sheet, so book value understates it. Comparing that P/B to a bank's would be meaningless. Always compare a company's P/B to its own history and to direct peers.
P/B alongside other ratios
P/B is one member of a family of valuation ratios. The price-to-earnings ratio compares price to profit rather than to assets, and the two answer different questions — one is about earning power, the other about asset backing. Value-minded investors often look at both, since a stock can look cheap on one measure and pricey on the other.
The bottom line
The price-to-book ratio compares a stock's price to the net assets backing each share, showing how many dollars investors pay per dollar of book value. Above 1 is typical; below 1 means the price sits under net asset value. But P/B only makes sense within an industry and alongside other measures — it's a lens for asking better questions, not a verdict on any stock.
Frequently asked
What is the price-to-book ratio?
The price-to-book (P/B) ratio compares a company's market value to its book value — how much investors are paying for each dollar of the company's net assets. It's calculated as share price divided by book value per share. A P/B of 2 means investors pay $2 for every $1 of net assets on the books.
What is a good price-to-book ratio?
There's no universal 'good' number — it depends heavily on the industry. Asset-heavy sectors like banks often trade near a P/B of 1, while tech companies can trade far higher because their value is intangible. A P/B below 1 means the price is below net asset value, which can signal a bargain or a troubled company.
How do you calculate the P/B ratio?
Divide the current share price by the book value per share. For example, a stock at $30 with book value per share of $15 has a P/B of 2.0. You can also calculate it at the company level by dividing total market cap by total shareholders' equity.
What does a P/B ratio below 1 mean?
A P/B below 1 means the market values the company at less than its net assets on the books. This can suggest the stock is undervalued, but it often reflects real problems — investors may expect losses, asset write-downs, or a shrinking business. A low P/B is a starting point for questions, not a buy signal.
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