We suggest an experimental design that can help opening the black box of investor behavior by documenting a channel of how biases affect portfolio performance. We study two of the most important investor biases (overreaction and overconfidence), show how they are related, and analyze their...

Investment clubs offer the opportunity to form a well-diversified portfolio with private investors being invested in that portfolio. Nevertheless, many investment clubs hold undiversified portfolios. We hypothesize that the clubs' composition and the characteristics of the decision making...