“Day-to-day fluctuations in the profits of existing investments, which are obviously of an ephemeral and non-significant character, tend to have an altogether excessive, and even an absurd, influence on the market. It is said, for example, that the shares of American companies which manufacture ice tend to sell at a higher price in summer when their profits are seasonally high than in winter when no one wants ice.”
– John Maynard Keynes (1936)
The fact that obvious information should be incorporated into the price of a stock seems…obvious. If information seems obvious at first glance, but in fact requires significant thought to understand, this information may not be reflected in a stock’s price. In this case the apparent obviousness of a given piece of information causes a person to feel as if they understand it and dismiss it without given the thought necessary to truly understand its content.