The Price to Book Ratio (PB), also known as the Price to Equity Ratio, is a financial ratio that compares a company's price per share to its book value per share. The book value per share is calculated by subtracting a company's liabilities from its assets and dividing by the total number of outstanding shares.

PB is another tool commonly used in fundamental analysis to evaluate a company's financial health and determine if a stock is overvalued or undervalued. A low PB can indicate that a stock is undervalued and may be a good buy, while a high PB may mean that the stock is overvalued and may be a sign to sell.

The formula for calculating PB is:

PB = Market Price per Share / Book Value per Share