Individual investors who hold common stocks directly pay a tremendous performance penalty for active trading. Of 66,465 households with accounts at a large discount broker during 1991 to 1996, those that trade most earn an annual return of 11.4 percent, while the market returns 17.9 percent. The average household earns an annual return of 16.4 percent, tilts its common stock investment toward high-beta, small, value stocks, and turns over 75 percent of its portfolio annually. Overconfidence can explain high trading levels and the resulting poor performance of individual investors. Our central message is that trading is hazardous to your wealth. The investor’s chief problem—and even his worst enemy—is likely to be himself. Benjamin Graham In 1996, approximately 47 percent of equity investments in the United States were held directly by households, 23 percent by pension funds, and 14 percent by mutual funds ~Securities Industry Fact Book, 1997!. Financial economists have extensively analyzed the return performance of equities managed by mutual funds. There is also a fair amount of research on the performance of equities managed by pension funds. Unfortunately, there is little research on the return performance of equities held directly by households, despite their large ownership of equities.

We examine changes in the stock trading behavior and investment performance of 1,607 investors who switch from phone based to online trading during the period 1992 to 1995. We document that young men who are active traders with high incomes and a preference for investing in small growth stocks with high market risk are more likely to switch to online trading. We also find that those who switch to online trading experience unusually strong performance prior to going online, beating the market by more than two percent annually. After going online, they trade more actively, more speculatively, and less profitably than before-- lagging the market by more than three percent annually. A rational response to reductions in market frictions (lower trading costs, improved execution speed, and greater ease of access) does not explain these findings. The increase in trading and reduction in performance of online investors can be explained by overconfidence augmented by self-attribution bias, the illusion of knowledge, and the illusion of control.

Individual investors who hold common stocks directly pay a tremendous performance penalty for active trading. Of 66,465 households with accounts at a large discount broker during 1991 to 1996, those that traded most earned an annual return of 11.4 percent, while the market returned 17.9 percent. The average household earned an annual return of 16.4 percent, tilted its common stock investment toward high-beta, small, value stocks, and turned over 75 percent of its portfolio annually. Overconfidence can explain high trading levels and the resulting poor performance of individual investors. Our central message is that trading is hazardous to your wealth. The investor’s chief problem-- and even his worst enemy--is likely to be himself. Benjamin Graham In 1996, approximately 47 percent of equity investments in the U.S. were held directly by households, 23 percent by pension funds, and 14 percent by mutual funds (Security Industry Fact Book, 1997). Financial economists have extensively analyzed the return performance of equities managed by mutual funds. There is also a fair amount of

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 the common 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’s net returns by 2.65 percentage points a year as opposed to 1.72 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, 19 th 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, rebalance their portfolios, and trade to minimize their taxes. Those possessed of superior information may trade speculatively,

Trading volume on the world’s markets seems high, perhaps higher than can be explained by models of rational markets. For example, the average annual turnover rate on the New York Stock Exchange (NYSE) is currently greater than 75 percent 1 and the daily trading volume of foreign-exchange transactions in all currencies (including forwards, swaps, and spot transactions) is roughly one-quarter of the total annual world trade and investment flow (James Dow and Gary Gorton, 1997). While this level of trade may seem disproportionate to investors’ rebalancing and hedging needs, we lack economic models that predict what trading volume in these market should be. In theoretical models trading volume ranges from zero (e.g., in rational expectation models without noise) to infinite (e.g., when traders dynamically hedge in the absence of trading costs). But without a model which predicts what trading volume