DEFINITION of 'Price Efficiency'
The premise that asset prices are efficient, to the extent that they already factor in or discount all available information. The theory of price efficiency follows from the efficient market hypothesis, which holds that since markets are efficient, it is nearly impossible for investors to "beat the market" on a consistent basis.
BREAKING DOWN 'Price Efficiency'
The three versions of the efficient market hypothesis (EMH) are all based on varying assumptions of price efficiency. The weak form of EMH claims that the prices of publiclytraded assets already reflect all available information, and past prices are of little value in predicting future trends. The semistrong version of EMH holds that while prices are efficient, they react instantaneously to new information, while the strong version of EMH maintains that asset prices reflect not just public knowledge, but private insider information as well.

Market Efficiency
The degree to which stock prices reflect all available, relevant ... 
Weak Form Efficiency
One of the different degrees of efficient market hypothesis (EMH) ... 
Efficient Market Hypothesis  EMH
An investment theory that states it is impossible to "beat the ... 
SemiStrong Form Efficiency
A class of EMH (Efficient Market Hypothesis) that implies all ... 
Discounting Mechanism
The premise that the stock market essentially discounts, or takes ... 
Strong Form Efficiency
The strongest version of market efficiency. It states all information ...

Active Trading
What Is Market Efficiency?
The efficient market hypothesis (EMH) suggests that stock prices fully reflect all available information in the market. Is this possible? 
Active Trading Fundamentals
Efficient Market Hypothesis: Is The Stock Market Efficient?
Deciding whether it's possible to attain aboveaverage returns requires an understanding of EMH. 
Professionals
Capital Market Efficiency
We look at the efficient market hypothesis and see if it holds up. 
Active Trading
Market Efficiency Basics
Market efficiency theory states that a stockâ€™s price will fully reflect all available and relevant information at any given time. 
Professionals
The Efficient Market Hypothesis
CFA Level 1  The Efficient Market Hypothesis. Learn the basics of the efficient market hypothesis. Includes the assumptions and expectations behind this theory on capital markets. 
Mutual Funds & ETFs
Efficient Market Hypothesis (EMH)
Efficient Market Hypothesis (EMH) 
Options & Futures
Financial Concepts: Efficient Market Hypothesis
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 incorporate and reflect all ... 
Professionals
Weak, SemiStrong and Strong EMH
CFA Level 1  Weak, SemiStrong and Strong EMH. Learn the aspects of the three forms of the efficient market hypothesis. Includes assumptions and testing methods of each form. 
Professionals
Implications of Efficient Markets
CFA Level 1  Implications of Efficient Markets. Learn how the efficient market hypothesis impacts technical analysis, portfolio management and index funds. 
Professionals
Market Anomalies
CFA Level 1  Market Anomalies. Learn six market anomalies and how investors can use them to their advantages. Provides overall conclusions on each form of EMH.

What does the efficient market hypothesis assume about fair value?
Found out what the efficient market hypothesis says about the fair value of securities, and learn why technical and fundamental ... Read Answer >> 
What are the primary assumptions of Efficient Market Hypothesis?
Find out about the key assumptions behind the efficient market hypothesis (EMH), its implications for investing and whether ... Read Answer >> 
Why does the efficient market hypothesis state that technical analysis is bunk?
Learn about why there are strong conceptual differences between the efficient market hypothesis and technical analysis about ... Read Answer >> 
What does the Efficient Market Hypothesis have to say about fundamental analysis?
Find out what the efficient markets hypothesis has to say about fundamental analysis and how recent finance research has ... Read Answer >> 
What are the differences between weak, strong and semistrong versions of the Efficient ...
Discover how the efficient market theory is broken down into three versions, the hallmarks of each and the anomalies that ... Read Answer >> 
Has the Efficient Market Hypothesis been proven correct or incorrect?
Explore the efficient market hypothesis and understand the extent to which this theory and its conclusions are correct or ... Read Answer >>