The price-to-book ratio (P/B) is used to compare a company’s book value to the current market price of its common shares. Book value is an accounting term that describes the company’s value determined by subtracting all of the company’s liabilities from the company’s assets as they are valued in its financial statements, not the asset’s current market value. The calculation can be performed in two ways, but the result should be the same each way. In the first way, the company’s market capitalization can be divided by the company’s total book value from its balance sheet. The second way, using per-share values, is to divide the company’s current share price by the book value per share (i.e. its book value divided by the number of outstanding shares).
As with most ratios, it varies a fair amount by industry. Industries that require more infrastructure capital (for each dollar of profit) will usually trade at P/B ratios much lower than, for example, consulting firms. P/B ratios are commonly used to compare banks because most assets and liabilities of banks are constantly valued at market values. A higher P/B ratio implies that investors expect management to create more value from a given set of assets, all else equal (and/or that the market value of the firm’s assets is significantly higher than their accounting value). P/B ratios do not, however, directly provide any information on the ability of the firm to generate profits or cash for shareholders.
The P/B ratio also gives some idea of whether an investor is paying too much for what would be left if the company went bankrupt immediately. For companies in distress, the book value is usually calculated without the intangible assets that would have no resale value. In such cases, P/B should also be calculated on a diluted basis because stock options may well vest on sale of the company or change of control or firing of management.