財(cái)務(wù)會(huì)計(jì)理論sccot第四章有效證券市場(chǎng)-文庫(kù)吧
2024-12-22 21:29 本頁(yè)面
【正文】 ted to new information almost instantly, not gradually as had been believed. The Efficient Markets Hypothesis ? The Efficient Markets Hypothesis (EMH) is made up of three progressively stronger forms: ?Weak Form ?Semistrong Form ?Strong Form The EMH Graphically ? In this diagram, the circles represent the amount of information that each form of the EMH includes. ? Note that the weak form covers the least amount of information, and the strong form covers all information. ? Also note that each successive form includes the previous ones. Str ong Form Semi Str ong Wea k Form All historical prices and returns All public information All information, public and private The Weak Form ? The weak form of the EMH says that past prices, volume, and other market statistics provide no information that can be used to predict future prices. ? If stock price changes are random, then past prices cannot be used to forecast future prices. ? Price changes should be random because it is information that drives these changes, and information arrives randomly. ? Prices should change very quickly and to the correct level when new information arrives (see next slide). ? This form of the EMH, if correct, repudiates technical analysis. ? Most research supports the notion that the markets are weak form efficient. The Semistrong Form ? The semistrong form says that prices fully reflect all publicly available information and expectations about the future. ? This suggests that prices adjust very rapidly to new information, and that old information cannot be used to earn superior returns. ? The semistrong form, if correct, repudiates fundamental analysis. ? Most studies find that the markets are reasonably efficient in this sense, but the evidence is somewhat mixed. The Strong Form ? The strong form says that prices fully reflect all information, whether publicly available or not. ? Even the knowledge of material, nonpublic information cannot be used
環(huán)評(píng)公示相關(guān)推薦
鄂ICP備17016276號(hào)-1