Benjamin Graham (/ɡræm/; né Grossbaum; May 9, 1894 – September 21, 1976) was a British-born American investor, economist, and professor. He is widely known as the "father of value investing," and wrote two of the founding texts in neoclassical investing: Security Analysis (1934) with David Dodd, and The Intelligent Investor (1949). His investment philosophy stressed investor psychology, minimal debt, buy-and-hold investing, fundamental analysis, concentrated diversification, buying within the margin of safety, activist investing, and contrarian mindsets.Read about Benjamin Graham in Wikipedia
In other words, the market is not a weighing machine, on which the value of each issue is recorded by an exact and impersonal mechanism, in accordance with its specific qualities. Rather should we say that the market is a voting machine, whereon countless individuals register choices which are the product partly of reason and partly of emotion.
It is our argument that a sufficiently low price can turn a security of mediocre quality into a sound investment opportunity - provided that the buyer is informed and experienced and he practices adequate diversification. For, if the price is low enough to create a substantial margin of safety, the security thereby meets our criterion of investment.
The history of the past fifty years, and longer, indicates that a diversified holding of representative common stocks will prove more profitable over a stretch of years than a bond portfolio, with one important provisio that the shares must be purchased at reasonable market levels, that is, levels that are reasonable in the light of fairly well-defined standards derived from past experience.