Value investing is an investment paradigm that derives from the ideas on investment that Ben Graham and David Dodd began teaching at Columbia Business School in 1928 and subsequently developed in their 1934 text Security Analysis. Although value investing has taken many forms since its inception, it generally involves buying securities that appear under priced by some form of fundamental analysis. As examples, such securities may be stock in public companies that trade at discounts to book value or tangible book value, have high dividend yields, have low price-to-earning multiples or have low price-to-book ratios. High-profile proponents of value investing, including Berkshire Hathaway chairman Warren Buffett, have argued that the essence of value investing is buying stocks at less than their intrinsic value.
The discount of the market price to the intrinsic value is what Benjamin Graham called the "margin of safety". The intrinsic value is the discounted value of all future distributions. However, the future distributions and the appropriate discount rate can only be assumptions. Graham never recommended using future numbers, only past ones). For the last 25 years, Warren Buffett has taken the value investing concept even further with a focus on "finding an outstanding company at a sensible price" rather than generic companies at a bargain price.
Graham never used the phrase, "value investing" — the term was coined later to help describe his ideas and has resulted in significant misinterpretation of his principles, the foremost being that Graham simply recommended cheap stocks.