PBR, or Price-to-Book Ratio, is a financial metric used to evaluate a company's market value relative to its book value. It is calculated by dividing the current share price by the book value per share. A lower PBR may indicate that a stock is undervalued, while a higher PBR could suggest overvaluation. Investors often use PBR to assess the attractiveness of a stock, especially in industries where tangible assets are significant. It is particularly useful for comparing companies within the same sector, as it helps identify potential investment opportunities based on asset valuation.