Final answer:
If a BD sells a penny stock as of the last trading day of any month, they must file a report with the SEC.
Step-by-step explanation:
The Securities and Exchange Commission (SEC) requires Broker-Dealers (BDs) to file a monthly report on the last trading day of every month if they sell penny stocks. These reports provide information on the BD's penny stock activities, including the number of shares sold, the price at which they were sold, and the amount received from the sales.
This requirement helps the SEC monitor penny stock activities and protects against potential fraudulent practices.