There are two efficient market hypotheses. One is the bold, unsubstantiated proposition that financial markets are close to perfect and all-knowing. This theory was ferociously and convincingly attacked by Robert Shiller and Lawrence Summers three decades ago and quietly abandoned by its progenitors in the 1990s – although it lived on zombie-style in textbooks, central bank policy and some parts of the financial press until recently. When, these days, a pundit or government official rails against “efficient market theory”, this is what they mean.
有效市场假说有两种：一种是大胆且未经证实的观点，认为金融市场近乎完美且无所不知。30年前，这种理论受到了罗伯特•希勒(Robert Shiller)和劳伦斯•萨默斯(Lawrence Summers)猛烈但令人信服的抨击。上世纪90年代，其创始人悄然放弃了这一理论——尽管直到最近，它还会在一些教科书、央行政策以及部分财经报道中借尸还魂。目前，当一位学者或政府官员指责“有效市场理论”时，他们指的就是这种假说。