(10)To ensure market data is provided on a RCB, market data providers should be able to set up categories of clients based on factual elements, including usage or size of the client. The categorisation of clients should allow market data providers to treat differently clients that present different factual characteristics. Clients within a category should be clearly distinguishable from clients in other categories by one or more elements which set them apart from clients in other categories. A client should only belong to one category. For instance, market data providers could create a separate client category for data redistributors, professional, or non-professional clients. The criteria used to set up categories of clients should be sufficiently general to be applicable to a group of clients. Therefore, categorisation should result in a limited number of categories.