History of the efficient market hypothesis.
. Banz (1981), in a major study of long-term returns on US shares, was the first to systematically document what had been known anecdotally for some years – namely, that shares in companies with small market capitalisations (‘small caps’) tended to deliver higher returns than those of larger companies. Banz's work was followed by a series of broadly corroborative studies in the US, the UK and elsewhere. Strangely enough, the last twenty years of the twentieth century saw a sharp reversal of this trend, so that over the century as a whole the ‘small cap’ effect was much less marked. Whatever the reason or reasons for this phenomenon, clearly there was a discernible pattern or trend that persisted for far too long to be readily explained as a temporary distortion within the general context of EMH.
Hypothesis on Chrome's recent market share boost - …
Observing correctly that the market was frequently efficient, they went on to conclude incorrectly that it was always efficient." Adherents to a stronger form of the EMH argue that the hypothesis does not preclude - indeed it predicts - the existence of unusually successful investors or funds occurring through chance.
The underlying argument of this theory is that it is not possible to beat the market because the market can neither be undervalued nor inflated. Rather, it is efficient. The price of a company’s shares incorporate all publicly available knowledge and as such are at their fair and correct level. Whether a share you’ve bought goes up in value or not therefore relies purely on unknown, future information. Nothing that has happened to the price in the past will have a bearing on its future movement. Anything that could affect its future movement is already accounted for in the present price.
In finance, the efficient market hypothesis (EMH) asserts that ..
In its strongest form, the EMH says a market is efficient if all information relevant to the value of a share, whether or not generally available to existing or potential investors, is quickly and accurately reflected in the market price. For example, if the current market price is lower than the value justified by some piece of held information, the holders of that information will exploit the pricing anomaly by buying the shares. They will continue doing so until this excess demand for the shares has driven the price up to the level supported by their private information. At this point they will have no incentive to continue buying, so they will withdraw from the market and the price will stabilise at this new equilibrium level. This is called the of the EMH. It is the most satisfying and compelling form of EMH in a theoretical sense, but it suffers from one big drawback in practice. It is difficult to confirm empirically, as the necessary research would be unlikely to win the cooperation of the relevant section of the financial community – insider dealers.
Hypothesis market research by Eleanor Banks - issuu
I would conclude that markets are inherently inefficient in their nature. Yes, efficient market hypothesis could work in an idealistic world, but that isn’t where we are.
What is the efficient market hypothesis
Gibson wrote that when “shares become publicly known in an open market, the value which they acquire may be regarded as the judgment of the best intelligence concerning them.”
Efficient market hypothesis and irrational investing
In 1965, Eugene Fama published his dissertation arguing for the random walk hypothesis and Samuelson published a proof for a version of the efficient market hypothesis.