In their landmark paper “Trading Is Hazardous to Your Wealth: The Common Stock Investment Performance of Individual Investors”, researchers at The Haas School at Berkeley note
“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.”
In another paper this time looking at retail traders return data from Taiwan titled “Just How Much Do Individual Investors Lose by Trading?”, researchers note
“Individual investor trading results in systematic and economically large losses. Using a complete trading history of all investors in Taiwan, we document that the aggregate portfolio of individuals suffers an annual performance penalty of 3.8 percentage points.”
Less comprehensive studies suggest that trading losses and costs for individual investors in the United States are about 2 percentage points a year. Also, retail traders quit trading at an alarming rate. About 75% of retail traders stop trading after 2 years, and as many as 90% stop after 4 years due to trading related account losses.
Over a savings horizon of 20 years, an annual return shortfall of 2% vs the index will result in a ~45% reduction in potential wealth and can dramatically change your lifestyle choices.
So if you thought ‘hey, there is no harm in some fun trading’, well that’s the cost of fun then. I am sure you can find more amusing and far cheaper options easily.