Security Analysis is arguably the most important book on value investing. You might be surprised, but there is no valuation methodology in the book. Benjamin Graham and David Dodd did not provide any indication that they used a formula or a specific algorithm for determining intrinsic value of common stocks.

The book, quite appropriately, is named "Security Analysis", not "Security Valuation". In the sections related to common-stock investment, it contains description of a general approach to selecting stocks. There is also a good treatise on how to adjust the income statement and balance sheet and what factors to look at in a comparison valuation. But you will be looking in vain for a well defined valuation process. Nonetheless, Security Analysis is a great book. It clearly distinguishes investing from speculation, and arms the investor with general guiding principles of investing.

The stock screener presented here is not the one used by the founders of the security analysis, but the one developed by us using the general approach to security valuation they employed. The stock screener compares intrinsic value of a stock with its current market price. The difference between them is called the margin of safety.

Contrary to common belief, Benjamin Graham and David Dodd did not provide any indication that they used a formula or a specific algorithm for determining intrinsic value of a common stock. According to them, "security analysis does not seek to determine exactly what is the intrinsic value of a given security". It can only asses if the price is low or high enough. The intrinsic value is a range with vaguely defined limits, not a specific number.

In The Intelligent Investor, Benjamin Graham provides a simple formula, that, in his own words, only "approximates the results of the more elaborate calculations in vogue" (i.e. other methods) for the valuation of growth stocks. He never actually suggested or implied that that the formula gives the "true value" of a growth stock. This formula appeared in the text in the context of the discussion how unreliable predictions of future growth rates are.

The formula was slightly revised in 1974 to adjust for variations in market interest rates and was described as follows:

Security Analysis

What is Value Investing according to Graham and Dodd?

In a few words - it is investing in undervalued securities, i.e. those securities intrinsic (or true) value of which is less than its market price. This is still how value investing is defined today. The difference, however, is in how the intrinsic value is determined.

Graham and Dodd define the intrinsic value as "value which is justified by the facts", which, by definition, cannot include "entirely conjectural future prospects". A true Graham and Dodd value investor would only take into consideration future prospects of a company when such prospects are certain and quantifiable. When they are either not certain or quantifiable, they are completely disregarded. This basically reduces all companies with volatile earnings to valuation based almost exclusively on balance sheet items.