If you are a trader that averages 390 options orders a day in a calendar month, then you could be classified as a professional trader. The number 390 is derived from the number of minutes in an ordinary trading day (9:30am to 4:00pm Eastern Time), hence placing a new order each minute of the trading day.

Orders submitted by professional traders will have a lesser priority in order execution comparative to non-professional traders. As a result of these special handling procedures, Firstrade does not support professional trading at this time.

This rule was first implemented by the CBOE (Chicago Board Options Exchange) and ISE (Nasdaq International Securities Exchange) to address investors that have access to information and technology that would effectively empower themselves to trade in the same manner as a market maker or broker-dealer. Although the CBOE and ISE initially implemented this rule, most other U.S. options exchanges have similarly implemented rules to distinguish orders as "Professional" in origin.

Each time a new option order has been sent (no matter if the order is executed or not), a new order number is generated and counted towards the 390 Rule. Orders that are canceled and replaced will generate a new order number and count towards the 390 Rule. Spread orders are considered a single order, regardless of the number of legs of the spread.

Firstrade is required to conduct a review on a quarterly calendar basis to identify those customers who have exceeded the 390-order threshold for any month in that quarter and who are to be classified as Professional Traders for the next calendar quarter.