These are articles written by professionals for investment professionals. They are contributions from external subject matter experts who do not work for CFA Institute, but may be a CFA charterholder as well as a member of a CFA Society. All are experts in their field and strive to deliver useful insights that help investment professionals make better decisions. Millions of retail investors opened up brokerage accounts this past year and many took to trading throughout the day as a way to pass the time, keep themselves entertained, and make a bit of money. So did all this trading actually help the average retail investor’s portfolio during the COVID-19–dominated months of 2020?