DEFINITION of 'Discounting Mechanism'
The premise that the stock market essentially discounts, or takes into consideration, all available information and present and potential future events. When unexpected developments occur, the market discounts this new information very rapidly. The Efficient Market Hypothesis (EMH) is based on the hypothesis that the stock market is a very efficient discounting mechanism.
BREAKING DOWN 'Discounting Mechanism'
The fact that the stock market is essentially a discounting mechanism explains the wild swings in stock indexes following unexpected events such as a natural disaster or a terrorist attack, or an earnings miss in the case of an individual stock. The efficiency of the stock market as a discounting mechanism has been vigorously debated over the years. Economist Paul Samuelson, attempting to show that equity markets do not always get it right, famously remarked in 1966 that "Wall Street indexes predicted nine out of the last five recessions."