What it means
Book value is what accountants say the shareholders own: total assets minus total liabilities, built up from historical cost less depreciation. Market value is what buyers and sellers of the shares think that ownership is worth today, based on expected future profits.
The gap between the two exists because accounting records what a business paid for things, while markets price what a business can earn from them. Brands, customer relationships, trained teams and software built in-house rarely appear on the balance sheet, yet they often drive most of the profit.
A ratio well above 1.0 suggests investors expect returns above the cost of the capital invested, which is common for software, pharmaceutical and consumer brand companies. A ratio below 1.0 signals the opposite: the market believes the assets will earn less than their recorded value, or that they will need writing down.
Value investors have long used a low market to book ratio as a screening tool for potentially underpriced shares. The screen is crude on its own, because a cheap-looking ratio often reflects a genuine problem such as obsolete plant, declining demand or heavy borrowing.
The ratio is least useful for asset-light businesses, where book equity is small and the ratio balloons for reasons that say little about quality. Comparisons only really work within an industry, and only when the companies use broadly similar accounting policies.
There is also a direct link between this ratio and profitability, because a company earning a high return on equity will normally trade at a high multiple of book value. As a rough guide, when return on equity matches the return investors demand, the ratio settles near 1.0, and every point of excess return pushes it higher.
In practice
Real-world examples.
Example
A private equity team screening listed engineering firms finds one trading at a market to book ratio of 0.7. Digging in, they discover the company owns freehold factories carried at 1990s cost, so book value understates reality and the shares may be genuinely cheap.
Example
A software company reports a market to book ratio of 12, which alarms a first-time investor. Its finance director explains that nearly all development spending is expensed rather than capitalised, so the balance sheet holds almost none of the value the customers actually pay for.
Example
A regional bank's ratio falls from 1.3 to 0.8 after a rise in loan defaults. Analysts read this as the market pricing in future write-downs of the loan book rather than as a bargain.
Think of it
“Market to book shows how the market values your company relative to accounting book value.
Formula
Calculation
Market to Book Ratio = Market Capitalisation / Book Value of Equity
Equivalently: Market to Book Ratio = Share Price / Book Value per Share
Worked example: a listed packaging manufacturer has 25,000,000 shares trading at $36.00 each, and its balance sheet shows total assets of $780,000,000 and total liabilities of $420,000,000.
Book value of equity = $780,000,000 - $420,000,000 = $360,000,000.
Market capitalisation = 25,000,000 x $36.00 = $900,000,000.
Market to Book Ratio = $900,000,000 / $360,000,000 = 2.5.
Checking it the per-share way: book value per share = $360,000,000 / 25,000,000 = $14.40, and $36.00 / $14.40 = 2.5. Investors are paying $2.50 for every $1.00 of recorded net assets.Case study
Seen in the real world.
This is an illustrative, fictional scenario. Harbourline Freight, an invented logistics group, listed with a market to book ratio of 1.1 and a balance sheet dominated by trucks and depots. Its chief executive complained that the market refused to recognise the strength of the business.
An adviser walked the board through the arithmetic in reverse. At a ratio near 1.0, investors were saying they expected Harbourline to earn roughly its cost of capital and no more, which matched a return on equity of 9% against a cost of equity around 9%.
Harbourline then sold two underused depots, repaid debt, and shifted capacity towards a higher-margin temperature-controlled service. Return on equity rose to 15% over two years, and the market to book ratio moved to 1.9 without the company issuing a single new share.
Watch out
Common mistakes.
- Assuming a ratio below 1.0 automatically signals a bargain, when it usually reflects poor expected returns or assets that are worth less than their carrying value.
- Comparing the ratio across very different industries, where accounting for assets differs so much that the numbers are not talking about the same thing.
- Forgetting that share buybacks reduce book equity, which mechanically raises the ratio without any change in the underlying business.
Questions
People also ask.
What is the difference between this and price to book?
Nothing of substance, since price to book is the same calculation expressed per share rather than in total.
Does a high ratio mean a company is overvalued?
Not by itself, because a high ratio is normal for businesses whose value sits in brands, patents and people rather than in recorded assets.
Can book value ever be negative?
Yes, when accumulated losses or large borrowings exceed assets, and the ratio then becomes meaningless and should not be reported.
From the founder's library
Take it further with the book.
Build your financial confidence beyond this definition. Shihan's full-length guide, Accounting Fundamentals, takes the same plain-English approach and turns it into a complete, practical playbook for non-finance managers, business owners and students - with chapter-end quiz answers and presentation slides included.
25% off with code MMHQ25, applied at checkout. Priced in USD - checkout may show the equivalent in your local currency.
View the book and save 25%