“all that trading can be hazardous to your wealth, as University of California, Berkeley professors Brad Barber and Terrance Odean put it in their 2000 study of investor trading behavior. The study looked at approximately 66,000 households using a discount broker between 1991 and 1996 and found that individuals who trade frequently (with monthly turnover above 8.8%) earned a net annualized return of 11.4% over that time, while inactive accounts netted 18.5%. Investors who traded most often paid the most in brokerage commissions, taking a huge bite out of returns. All of that trading might've been worthwhile if investors replaced the stocks they sold with something better. But interestingly, the study found that, excluding trading costs, newly acquired stocks actually slightly underperformed the stocks that were sold. That means that rapid traders' returns suffered whether or not fees were taken into account. Some researchers have come to a similar conclusion studying fund manager trading--standing pat is often the best strategy. ”
