A stock market bubble is a type of economic bubble taking place in stock markets when market participants drive stock prices above their value in relation to some system of stock valuation.
Behavioral finance theory attributes stock market bubbles to cognitive biases that lead to groupthink and herd behavior. Bubbles occur not only in real-world markets, with their inherent uncertainty and noise, but also in highly predictable experimental markets. In the laboratory, uncertainty is eliminated and calculating the expected returns should be a simple mathematical exercise, because participants are endowed with assets that are defined to have a finite lifespan and a known probability distribution of dividends. Other theoretical explanations of stock market bubbles have suggested that they are rational, intrinsic, and contagious.
Read more about Stock Market Bubble: Examples, Whether Rational or Irrational, Positive Feedback, Effect of Incentives
Famous quotes containing the words stock, market and/or bubble:
“And anyone is free to condemn me to death
If he leaves it to nature to carry out the sentence.
I shall will to the common stock of air my breath
And pay a death tax of fairly polite repentance.”
—Robert Frost (1874–1963)
“When General Motors has to go to the bathroom ten times a day, the whole country’s ready to let go. You heard of that market crash in ‘29? I predicted that.... I was nursing a director of General Motors. Kidney ailment, they said; nerves, I said. Then I asked myself, “What’s General Motors got to be nervous about?” “Overproduction,” I says. “Collapse.””
—John Michael Hayes (b. 1919)
“While this America settles in the mould of its vulgarity, heavily
thickening to empire,
And protest, only a bubble in the molten mass, pops and sighs out,
and the mass hardens,”
—Robinson Jeffers (1887–1962)