I realize that the scenario I painted is very unlikely. However, the only reason I bring this up is that the same individual could have "trader status" one year according to the IRS and then the next year they might not (maybe their trading strategy changed during the year and their frequency of trading dramatically decreased). The fact is, it is possible that the individual does not know if they will achieve trader status in the eyes of the IRS at the beginning of the year.
Does the non-professional/professional qualification hinge upon whether this individual has trader status? I.e., because they qualify for trader status, they are then classified as a sole proprietorship?
The trader status qualification is a tax issue, and can be decided after the tax year is over. The non-professional/professional fees qualification is a real-time issue. For the sake of argument, let's assume that being a sole proprietor implies that you have to pay professional fees. And if you qualify for trader tax status, you are necessarily labeled a sole proprietor. Then, what I am saying is that whether you pay non-professional/professional fees hinges upon the exact moment that you can declare yourself to have trader tax status for that year.
And one more thing to put in the mix. There has been at least one IRS court case brought against a trader who claimed trader tax status but only traded regularly for a portion of the year. I believe the IRS won the court case so the individual could not claim trader tax status. Therefore, suppose an individual trades the first quarter of the year and thinks they will have trader tax status, but then they start losing money and decide to lay low while doing research the rest of the year. At what point do they pay professional fees? At what point do they revert back to non-professional fees?
The easiest way of interpreting this issue is that you pay professional fees if you are an entity or you are employed by a financial company. You pay non-professional fees if you are an individual with an account in your own name, even if the IRS treats you as if you are a sole proprietorship. I.e., the IRS classification does not count towards determining the professional/non-professional qualification.