(66)When establishing its execution policy in accordance with Article 21(2) of Directive 2004/39/EC, an investment firm should determine the relative importance of the factors mentioned in Article 21(1) of that Directive, or at least establish the process by which it determines the relative importance of these factors, so that it can deliver the best possible result to its clients. In order to give effect to that policy, an investment firm should select the execution venues that enable it to obtain on a consistent basis the best possible result for the execution of client orders. An investment firm should apply its execution policy to each client order that it executes with a view to obtaining the best possible result for the client in accordance with that policy. The obligation under Directive 2004/39/EC to take all reasonable steps to obtain the best possible result for the client should not be treated as requiring an investment firm to include in its execution policy all available execution venues.