The New Finance focused on the market's major systematic mistake. In failing to appreciate the strength of competitive forces in a market economy, it over estimates the length of the short run. In doing so, it overreacts to records of success and failure for individual companies, driving the prices of successful firms too high and their unsuccessful counterparts too low.
The investor has the benefit of the stock market's daily and changing appraisal of his holdings, for whatever that appraisal may be worth , and, second, that the investor is able to increase or decrease his investment at the market's daily figure if he chooses . Thus the existence of a quoted market gives the investor certain options which he does not have if his security is unquoted. But it does not impose the current quotation on an investor who prefers to take his idea of value from some other source.benjamin graham
The purchase of a bargain issue presupposes that the market's current appraisal is wrong, or at least that the buyer's idea of value is more likely to be right than the market's. In this process the investor sets his judgement against that of the market. To some this may seem arrogant or foolhardy.benjamin graham