不要混淆股票价格“变化”的随机性和 股价“水平”的非理性两个概念 如果股价是理性确定的,则只有新信息才导 致股价的变化 股价的随机游走正是股价反映所有现在信息 的自然表现
不要混淆股票价格“变化”的随机性和 股价“水平”的非理性两个概念 – 如果股价是理性确定的，则只有新信息才导 致股价的变化。 – 股价的随机游走正是股价反映所有现在信息 的自然表现
反之,如果股票价格不是随机变动而是 可以预测的,则表明所有的相关信息并 没有完仝反映在价格中,这表明市场是 非有效的 股票价格反映了所有可得信息称为有效 性市场假设
反之，如果股票价格不是随机变动而是 可以预测的，则表明所有的相关信息并 没有完全反映在价格中，这表明市场是 非有效的。 股票价格反映了所有可得信息称为有效 性市场假设
3.竞争是市场有效的根源 Why should we expect stock prices to reflect all available information>? 些例子 Grossman and Stiglitz的结果 不同市场的有效性不同:中国和美国的股市 小股票和大股票的有效性不同
3. 竞争是市场有效的根源 Why should we expect stock prices to reflect “all available information”? 一些例子 – Grossman and Stiglitz的结果 – 不同市场的有效性不同：中国和美国的股市 – 小股票和大股票的有效性不同
Although it may not literally be true that all relevant information will be uncovered. it is virtually certain that there are many investigators hot on the trail of most leads that seem likely to improve investment performance Competition among these many well-backed, highly paid, aggressive analysts ensures that, as a general rule stock prices ought to reflect available nformation regarding their proper levels
Although it may not literally be true that all relevant information will be uncovered, it is virtually certain that there are many investigators hot on the trail of most leads that seem likely to improve investment performance. Competition among these many well-backed,highly paid, aggressive analysts ensures that, as a general rule, stock prices ought to reflect available information regarding their proper levels