Consistency is an important factor to long term investment success. Value investing has been one method that, during the 1970s and 1980s delivered superior returns. In theory these stocks will rise over time as the market recognizes the value of the company. Graham is credited with being a pioneer in the area of portfolio analysis and was one of the first people to examine historical and current corporate data in an empirical way. Value investing will always be an important tool in portfolio creation.
Information flows faster.
The US stock market has become more liquid, with many more investors. The increase in investment has resulted in an increase in the number of stock market analysts that follow large and medium sized companies. This makes identifying truly under-priced stocks more difficult. In many cases unrecognized value can only be found in small to medium sized companies which are not covered by many analysts. The availability of cheap computing power and extensive stock market and corporate information databases has allowed the development of portfolio analysis and creation techniques that were unavailable to Benjamin Graham.