Confidence and the welfare of less-informed investors
实验发现，信息较少的投资者因过度自信而交易过于激进，导致财富向信息较多的投资者转移；但若提醒其信息劣势，则可消除福利损失。
In response to recommendations by the AICPA Special Committee on Financial Reporting and the Association for Investment Management and Research, the FASB recently invited comment regarding the question, “Given [efficient] markets, would any disservice be done to the interests of individual investors by allowing professional investors access to more extensive information?” [AICPA (1996) Report of the Special Committee on Financial Reporting and the Association for Investment Management and Research, New York, p. 22]. Research in psychology [e.g. Griffin & Tversky (1992) The weighing of evidence and the determinants of confidence. Cognitive Psychology, 411–435] suggests that less-informed investors may suffer from over-confidence and trade too aggressively given their information. This paper reports on an experiment designed to address these issues. In the experiment, security values are determined by the price/book ratios of actual firms, “more-informed” investors observe three value-relevant financial ratios derived from Value-Line reports, and “less-informed” investors observe only one of those signals. Even after market prices have stabilized after many rounds of trading, less-informed investors systematically transfer wealth to more-informed investors as a result of biased prices and overly aggressive trading. However, alerting less-informed investors to the extent of their informational disadvantage eliminates these welfare losses. The results thus suggest that providing information to only professional investors could harm the welfare of less-informed investors if less-informed investors are not aware of the extent of their informational disadvantage.