STREET DOGS: Hidden traps in investor thinking
The efficient market theory should inform our decisions but not dominate them
“Random Walk helped make famous an old joke about the economist who wouldn’t pick up a $100 bill on the street, reasoning that if it was really there someone else would have taken it. A better version would be to remember that if any $100 bills are lying around they will not be there for long,” — Burton Malkiel.
What about the major stock markets, such as the New York Stock Exchange? Here millions of people are prospecting, driven by the desire for profit. They’re all similarly informed; in fact, it’s one of the goals of our market regulation that everyone should gain access to the same company information at the same time. With millions of people doing similar analysis on the basis of similar information, how often will stocks become mispriced, and how regularly can any one person detect those mispricings?..