Those who adhere to the random walk theory also point out that the timing of new data and news is unpredictable, and that stock prices react quickly to the introduction of new information.

FORBES: Are Stock Prices Random Or Chaotic?

Authors Guofo Zhou and Yingzi Zu use some complex math based on the random-walk theory to show that the odds of watching half your liquid net worth evaporate are roughly similar to those of another major life event: death.

FORBES: We Can't Avoid Another Market Crash

The simplest theory is that these swellings dwindled to nothing after our ancestors began to walk upright, because the costs of advertising ovulation in this way came to outweigh any benefits.

NEWYORKER: It Ain��t Necessarily So