# Book-to-Market Ratio

A ratio used to find the value of a company by comparing the book value of a firm to its market value. Book value is calculated by looking at the firm's historical cost, or accounting value. Market value is determined in the stock market through its market capitalization.

Formula:

$Book-to-Market Ratio = Common Shareholders Equity Market Cap$

Most investors are more familiar with P/B or Price-to-book. This is just the inverted value.

$Price-to-Book Ratio = Market Cap Common Shareholders Equity$

We use Book-To-Market in our stock screener as it makes sure that companies with a negative value don't show up at the top of the list. We do include it in the scorecard as P/B is presented alongside the P/E, P/S and P/CF ratio.