P/E Ratio of <= 10    🙂 Underpriced

P/E Ratio of  = 15 Fairly Priced

P/E Ratio of  > = 30  Extreme Bubble

P/B Ratio (Price per share/ Book Value per share Ratio)

P/B < 1 = undervalued

P/B < 3 = Fair

P/B > 3 = Overvalued

Warren Buffett and the Interpretation of Financial Statements: https://amzn.to/2RRXkUt Security Analysis: https://amzn.to/2FmQtAY