The study found that year-over-year, only two groups of active managers successfully outperformed passive funds more than 50 percent of the time—U. small growth funds and diversified emerging markets funds.
The Efficient Market Hypothesis, or EMH, is an investment theory whereby share prices reflect all information and consistent alpha generation is impossible.
Theoretically, neither technical nor fundamental analysis can produce risk-adjusted excess returns, or alpha, consistently and only inside information can result in outsized risk-adjusted returns.
Data compiled by Morningstar Inc., in its June 2015 Active/Passive Barometer study, supports the EMH.
Morningstar compared active managers’ returns in all categories against a composite made of related index funds and exchange-traded funds (ETFs).
According to the theory of the efficient as prices react to similar information there is no investor who will be in a position to earn superior profits over the other.
This kind of observation is seen in strong form efficiency where all available public information is incorporated in the stock’s price (Zhang, 2008; p. Using the random Walk theory asserts that in any efficient market, prices normally become unpredictable such that they are random.
For example, investors such as Warren Buffett have consistently beaten the market over long periods of time, which by definition is impossible according to the EMH. While a percentage of active managers do outperform passive funds at some point, the challenge for investors is being able to identify which ones will do so over the long-term.
Detractors of the EMH also point to events such as the 1987 stock market crash, when the Dow Jones Industrial Average (DJIA) fell by over 20 percent in a single day, as evidence that stock prices can seriously deviate from their fair values. Less than 25 percent of the top-performing active managers are able to consistently outperform their passive manager counterparts over time.
https://studentshare.org/macro-microeconomics/1499800-see-details-below-master-essay...the existence of efficient markets. Many are also involved in identifying the stocks that are mispriced.
When more and more investment advisors or the market analysts spend time in taking the advantage from the stocks that are either lowly priced or highly priced, the probability of detecting the securities that are mispriced becomes smaller.