文档介绍：Boys will be Boys:
Gender, Overconfidence, mon Stock Investment
Brad M. Barber* and Terrance Odean*
First Draft: September 1998
This Draft: September 1999

* We are grateful to the discount brokerage firm that provided us with the data for this study. We appreciate
ments of David Hirshleifer, Andrew Karolyi, Edward Opton Jr., Sylvester Schieber, Martha
Starr-McCluer, Richard Thaler and seminar participants at the University of Alberta, Arizona State
University, INSEAD, the London Business School, the University of Michigan, the University of
Vienna, the Institute on Psychology and Markets, and the Conference on Household Portfolio Decision-
making and Asset Holdings at the University of Pennsylvania. All errors are our own. Terrance Odean
can be reached at (530) 752-5332 or ******@; Brad Barber can be reached at (530) 752-0512
or ******@.
Boys will be Boys:
Gender, Overconfidence, mon Stock Investment
Abstract
Theoretical models predict that overconfident investors trade excessively. We test this
prediction by partitioning investors on gender. Psychological research demonstrates that,
in areas such as finance, men are more overconfident than women. Thus, theory predicts
that men will trade more excessively than women. Using account data for over 35,000
households from a large discount brokerage, we analyze mon stock investments
of men and women from February 1991 through January 1997. We document that men
trade 45 percent more than women. Trading reduces men’ returns by
percentage points a year as opposed to percentage points for women.
It’s not what a man don’t know that makes him a fool,
but what he does know that ain’t so.
Josh Billings, 19th century American humorist
It is difficult to reconcile the volume of trading observed in equity markets with
the trading needs of rational investors. Rational investors make periodic contributions and
withdrawals from their investment portfolios,