The academic concept of efficient market theory that prices already reflect all available information has led to the creation of index-tracking funds that allow investors to own a diversified portfolio at very low cost.

ECONOMIST: Investment management

Research Chairman Eisenstadt takes great satisfaction in having proved to adherents of the efficient market theory that the market can, in fact, be beaten.

FORBES: Magazine Article

At first glance, it may be easy to see a number of deficiencies in the efficient market theory, created in the 1970s by Eugene Fama.

FORBES: by Jason Van Bergen

In the past decade some economists have challenged efficient-market theory, by finding numerous examples of apparently predictable movements in share prices.

ECONOMIST: Heads, shoulders and broadening bottoms | The