报告题目：EFFORT, EFFICIENCY AND WELFARE

内容摘要：In the Grossman-Stiglitz model of noisy rational expectation, it is well known that the more information prices convey, the worse off everybody can be. In other words, there is a negative relationship between price efficiency and social welfare. We show that this result can be reverted when instead of paying a fixed cost for information, investors are uncertain whether they will become informed, and can make an effort to reduce this uncertainty. The optimal choice of the probability for investors to become informed can be characterized in a noncooperative Nash equilibrium game of information acquisition. We show that price efficiency can improve investors' welfare when the disutility of the effort is a convex function of the probability to become informed. Thus information acquisition is not always welfare-reducing as the literature suggests.