Efficient Market Hypothesis

9025 Words Feb 20th, 2012 37 Pages
The efficient markets hypothesis (EMH) is a dominant financial markets theory developed by Michael Jensen, a graduate of the University of Chicago and one of the creators of the efficient markets hypothesis, stated that, “there is no other proposition in economics which has more solid empirical evidence supporting it than the Efficient Markets Hypothesis” [Jensen, 1978, 96]. This paper analyzes whether it is possible to measure if markets are efficient in the strong form of EMH. A generation ago, the efficient market hypothesis was widely accepted by academic financial economists; for example, Eugene Fama’s (1970) influential survey article, “Efficient Capital Markets.” It was generally believed that securities markets were
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This implies that it is impossible to beat the market. Many studies shed light on whether investment advisers and mutual funds (some of which charge steep sales commissions to people who purchase them) beat the market. One common test that has been performed is to take buy and sell recommendations from a group of advisers or mutual funds and compare the performance of the resulting selection of stocks with the market as a whole. Sometimes the advisers’ choices have even been compared to a group of stocks chosen by throwing darts at a copy of the financial page of the newspaper tacked to a dartboard. The Wall Street Journal, for example, used to have a regular feature called “Investment Dartboard” that compared how well stocks picked by investment advisers did relative to stocks picked by throwing darts. Did the advisers win? To their embarrassment, the dartboard beat them as often as they beat the dartboard. Furthermore, even when the comparison included only advisers who had been successful in the past in predicting the stock market, the advisers still didn’t regularly beat the dartboard. Consistent with the efficient market hypothesis, mutual funds also do not beat the market. Not only do mutual funds not outperform the market on average, but when they are separated into groups according to whether they had the highest or lowest profits in a chosen period, the
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