Efficient Market Hypothesis - Definition for Efficient Market Hypothesis from Morningstar - A market theory that evolved from a 1960's Ph.D. dissertation. In finance, the efficient - market hypothesis (EMH), or the joint hypothesis problem, asserts that financial markets are "informationally efficient ". In consequence of. Investor Home - The Efficient Market Hypothesis and Random Walk Theory. Efficient market hypothesis (EMH) is an idea partly developed in the 1960s by Eugene Fama. It states that it is impossible to beat the market because prices already. Definition. The Efficient Market Hypothesis (EMH) is a controversial theory that states that security prices reflect all available information, making it fruitless to. Efficient Market Hypothesis States that all relevant information is fully and immediately reflected in a security's market price , thereby assuming that an investor. Definition of Efficient Market Theory: The (now largely discredited) theory that all market participants receive and act on all of the relevant. An investment theory that states it is impossible to "beat the market " because stock market efficiency causes existing share prices to always incorporate and reflect. The Efficient Market Hypothesis and Its Critics Burton G. Malkiel Abstract Revolutions often spawn counterrevolutions and the efficient market hypothesis This article introduces the concept of the efficient markets hypothesis .