(124)To ensure that fees for market data are set at a reasonable level, the fulfilment of the obligation to provide market data on a reasonable commercial basis requires that prices be based on a reasonable relationship to the cost of producing and disseminating that data. Therefore, without prejudice to the application of competition rules, data providers should determine their fees on the basis of their costs whilst being allowed to obtain a reasonable margin, based on factors such as the operating profit margin, the return on costs, the return on operating assets and the return on capital. Where data providers incur joint costs for data provision and the provision of other services, costs of data provision may include an appropriate share of costs arising from any other relevant service provided. Since specifying the exact cost is very complex, cost allocation and cost apportionment methodologies should be specified instead, leaving the specification of those costs to the discretion of market data providers.