Our study suggests that despite the enforcement of insider trading laws, there are still some investors trading on their private information. Using account-level information, we show that some retail investors seem to be informed about particular stocks. When they sell short these stocks, they...

Overall, 72 subjects invest their endowment in four risky assets. Each com-bination of assets yields the same expected return and variance of returns. Illusion of expertise prevails when one prefers nevertheless the self-selected portfolio. After being randomly assigned to groups of four...