What You Pay, What You Get: Connecting Price and Expected Returns
It has been more than 50 years since the idea of stock prices containing all relevant information was put forth. Information might come in the form of data from a company’s financial statements, news about a new product, a change in the regulatory environment, or simply a shift of investors’ tastes and preferences toward owning different investments.
Information is incorporated into security prices through the buying and selling process. While fair prices may not depend on a certain level of trading, over $400 billion of stocks traded on average each day in the world equity markets suggests that a great deal of information is incorporated into stock prices.