The classification of subscribers as "Professional" or "Non-Professional" is by exchange designation. Note that virtually all exchanges are for-profit institutions, with market data subscriptions being a key source of their revenue. As trading is considered the principal business activity of Professional Subscribers and real-time quotes essential to their business, the exchanges tend to charge accordingly. In contrast, trading is considered an incidental activity for Non-Professionals, many of whose needs can be met with free delayed data. The Non-Professionals are therefore offered quote services at subscription rates which are intended to reflect their occasional use and the fact they can avail themselves of free delayed data.
Information on the specific criteria used for Professional subscription status can be found in our Knowledge Base.