论文代写：市场效率概念
市场效率的概念在金融经济学领域受到了争论。然而，同样有争议的是市场效率的定义。1970年，美国经济学家尤金·法玛对市场效率的概念进行了全面的研究。在他的调查中，他定义了有效市场的定义。必须指出的是，他提出了一种有效的市场价格，这与充分获得信息有关。这种现象被称为有效市场假说(EMH)。根据EMH的说法，资产价格必须“充分反映”所有可用信息。EMH的目标是，由于市场价格对新信息和贴现率变化敏感，因此不可能打败市场。通过他的考试，Fama(1970)承认了三种形式的EMH，即弱形式，半强形式和强形式。EMH的弱形式表明，在过去的几年里，资产价格无法预测未来的资产价格，因为它们不构成新的信息。半强劲的形式表明，未来的资产价格无法根据已公布的信息预测。这是因为公布的信息是由投资者获得的，这导致了当前资产价格的调整。强大的形式代表了所有类型的信息(无论是来自私人的还是公共的)都反映在资产过程中(Fama,1970)。
论文代写：市场效率概念
然而，Fama(1970)的市场效率的定义在Jenson(1978)和Grossmanand Stiglitz(1980)中得到了增强，因为它们将信息成本和交易成本纳入了市场效率的范围之内。名声(1991年)然后继续即兴发挥他的市场效率定义，并指出市场效率受到连续统一体的影响。根据Jones和Netter(2008)所做的研究工作，发现Fama(1991)对交易成本和市场效率持怀疑态度。他接着说，如果交易成本和获取信息的成本降低，市场效率可以持续下去。在Fama(1991)的研究工作中，他提出了基于资产价格的信息效率可以在两大类中推导出来。第一，投资者只有在获得超额回报的情况下才对交易策略敏感。第二，反映所有信息的股票价格可能会促进新投资资本的最高价值使用(Fama,1991)。
论文代写：市场效率概念
The concept of market efficiency is subject to debate in the field of financial economics. However the equally debatable is the definition of market efficiency. In the year 1970, Eugene Fama, an American economist had conducted a comprehensive examination of the concept of market efficiency. In his investigation, he framed the definition of efficient markets. It must be noted that he suggested an efficient market price which is associated with the full availability of information. This phenomenon was referred to as the Efficient-Market Hypothesis (EMH). According to EMH, the asset prices must ‘fully reflect’ all available information. The aim of the EMH is that since market prices are sensitive to new information and discount rate changes, it would be impossible to beat the market. Through his examination, Fama (1970) recognized three forms of EMH which are the weak form, semi-strong form and the strong form. The weak form of EMH suggests that the future asset price could not be forecasted by the asset prices in the past years as they constitute no new information. The semi-strong form suggests that the future asset prices could not be predicted based on the published information. This is because the published information is acquired by the investors and this leads to the adjustment in the current asset prices. The strong form represents the idea that all kinds of information (either from private or public) is reflected in the asset process (Fama, 1970).
论文代写：市场效率概念
However, the definition of market efficiency of Fama (1970) was enhanced by Jenson (1978) and Grossmanand Stiglitz (1980) as they incorporated the cost of information and the transaction costs within the purview of market efficiency. Fame (1991) then went on to improvise his market efficiency definition and noted that the market efficiency is subject to the continuum. Based on the research work conducted by Jones and Netter (2008), it was revealed that Fama (1991) had been skeptical about the transaction costs and the market efficiency. He then stated that the market efficiency can be sustained if the transaction cost and the cost of obtaining information are lowered. In this research works of Fama (1991), he propounded that the informational efficiency based on the asset prices can be deduced under two broad categories. The first is that the investors are sensitive to the trading strategies only if it earns an excess return. The second is that the stock prices which reflect all information are likely to promote the highest valued use of the new investment capital (Fama, 1991).
