Efficientmarket hypothesis  Wikipedia
Investor Home  The Efficient Market Hypothesis
Efficient Market Hypothesis: Is The Stock Market Efficient?
The Efficient Market Hypothesis (EMH) has long been a staple among academics and business schools. The basic premise behind EMH is that markets are efficient in the processing of information; meaning that stock prices always reflect all publicly known facts, and as new facts become public knowledge, the market instantly updates this information and the stock price fluctuates accordingly.
Basically, the Efficient Market Hypothesis says that there can be no edge in the market, that investors are all perfectly rational, and all investors working off public information can’t profit except from inside information (and even then, maybe not), and that all stocks are equally well priced. There are various degrees of strictness of the theory, but the main point is that the market works like a .
Efficient Markets Hypothesis: History
All of that points to one conclusion: there is a way to beat the market. It may be temporary, it may be difficult, and it may take patience – but there has to be a way. Even if that ‘way’ can be captured by only 1% of investors, the Efficient Market Hypothesis is still disproved.
Do you consider yourself an active or a passive investor? What do you think of the Efficient Market Hypothesis? Can market be ‘beat’? What’s your strategy for investing?
History of the efficient market hypothesis.
"One of the reasons for this state of affairs is the fact that the Efficient Markets Hypothesis, by itself, is not a welldefined and empirically refutable hypothesis. To make it operational, one must specify additional structure, e.g., investor’ preferences, information structure, business conditions, etc. But then a test of the Efficient Markets Hypothesis becomes a test of several auxiliary hypotheses as well, and a rejection of such a joint hypothesis tells us little about which aspect of the joint hypothesis is inconsistent with the data. Are stock prices too volatile because markets are inefficient, or is it due to risk aversion, or dividend smoothing? All three inferences are consistent with the data. Moreover, new statistical tests designed to distinguish among them will no doubt require auxiliary hypotheses of their own which, in turn, may be questioned."
Lo and MacKinlay (1999), pages 67
One of the reasons for this state of affairs is the fact that the EMH, by itself, is not a welldefined and empirically refutable hypothesis. To make it operational, one must specify additional structure, e.g. investors' preferences, information structure. But then a test of the EMH becomes a test of several auxiliary hypotheses as well, and a rejection of such a joint hypothesis tells us little about which aspect of the joint hypothesis is inconsistent with the data. Are stock prices too volatile because markets are inefficient, or is it due to risk aversion, or dividend smoothing? All three inferences are consistent with the data. Moreover, new statistical tests designed to distinguish among them will no doubt require auxiliary hypotheses of their own which, in turn, may be questioned."
Lo in Lo (1997), page
Efficient Markets Hypothesis Foundations  Asset Class …

What is the efficientmarket hypothesis?  Quora
Under the efficientmarkets hypothesis, a worthless digital currency should have never gotten off the ground.

Why the efficient markets hypothesis merited a Nobel
14/10/2013 · The father of the Efficient Markets Hypothesis finally gets the respect he deserves.

Implications Of Efficient Market Hypothesis  …
01/06/2017 · First let’s talk about what Efficient Market Hypothesis is
Efficient markets hypothesis  Wikinvest
"The notion of market efficiency is not a wellposed and empirically refutable hypothesis. To make it operational, one must specify additional structure, e.g., investors’ preferences, information structure, etc. But then a test of market efficiency becomes a test of several auxiliary hypotheses as well, and a rejection of such a joint hypothesis tells us little about which aspect of the joint hypothesis is inconsistent with the data."
Lo (2000) in Cootner (1964), page x
Today begins a fourpart series on the efficient market hypothesis
The Efficient Market hypothesis is an excellent control and null hypothesis, but breaks down a fair amount of the time in markets – and not just the financial ones.
Efficient Markets Hypothesis  Revolvy
"First, any test of efficiency must assume an equilibrium model that defines normal security returns. If efficiency is rejected, this could be because the market is truly inefficient or because an incorrect equilibrium model has been assumed. This joint hypothesis problem means that market efficiency as such can never be rejected."
Campbell, Lo and MacKinlay (1997), page 24
Lecture Notes  Efficient Market Hypothesis  …
In the passive corner, the strongest evidence there is that what they are doing is optimal is the theory known as the Efficient Market Hypothesis (and its various offshoots, such as CAPM).
Efficient Market Hypothesis Emh Definition from …
One big hole in EMH is for markets to operate efficiently there needs to be transparency. The recent financial meltdown revealed how a lack of transparency in derivative type investments nearly destroyed our economy.