(79)In order to ensure investors receive information about all costs and charges pursuant to Article 24(4) of Directive 2014/65/EU, the underlying market risk should be understood as relating only to movements in the value of capital invested caused directly by movements in the value of underlying assets. Transactions costs and ongoing charges on financial instruments should therefore also be included in the required aggregation of costs and charges and should be estimated using reasonable assumptions, accompanied by an explanation that such estimations are based on assumptions and may deviate from costs and charges that will actually be incurred. Following the same objective of full disclosure, practices where there is ‘netting’ of costs should not be excluded from the obligation to provide information on costs and charges. The costs and charges disclosure is underpinned by the principle that every difference between the price of a position for the firm and the respective price for the client should be disclosed, including mark-ups and mark-downs.