Why a multiple is not an answer
P/E and P/B compare a share price with earnings or book value. A low number is not automatically undervalued, and a high number is not automatically a bubble. Growth, risk, capital efficiency, and the durability of profit are all reflected in the price, so a multiple should begin the research rather than end it.
Inspect the earnings in P/E
P/E normally divides price by earnings per share. The result can be distorted when net income contains an asset sale, unusual tax benefit, or valuation gain. P/E may be meaningless for a loss-making company, while unusually high profit near the top of a business cycle can make a cyclical company look deceptively cheap.
P/B and asset quality
P/B compares price with accounting equity, but assets do not all have the same quality. Cash, factories, inventory, and goodwill differ in recoverability and earning power. Book value can be central to some financial businesses and much less informative for a company whose value comes from internally developed intangible assets.
Compare similar businesses
Compare multiples among businesses with similar accounting and economics. Even within one industry, differences in growth, leverage, geography, and customer concentration can justify different ranges. Combine a peer comparison with the company’s own historical range to see what expectations the current price may contain.
Cycles and one-time items
For industries with volatile profits, one year of earnings may not represent normal conditions. If management presents adjusted earnings, check the filing to decide whether excluded costs are truly unusual. A restructuring charge that appears repeatedly is part of the economics even if it is labeled non-recurring each year.
Use valuation to form questions
After calculating P/E or P/B, ask why the market assigned that multiple. Are earnings repeatable, do the assets generate cash, does debt amplify the risk, and is the share count changing? A useful valuation process connects several pieces of evidence instead of searching for a single cheap-or-expensive score.