In these circumstances, the tax administration can consider ex post outcomes as presumptive evidence about the appropriateness of the ex ante pricing arrangements. However, the consideration of ex post evidence should be based on a determination that such evidence is necessary to be taken into account to assess the reliability of the information on which ex ante pricing has been based. Where the tax administration is able to confirm the reliability of the information on which ex ante pricing has been based, notwithstanding the approach described in this section, then adjustments based on ex post profit levels should not be made. In evaluating the ex ante pricing arrangements, the tax administration is entitled to use the ex post evidence about financial outcomes to inform the determination of the arm’s length pricing arrangements, including any contingent pricing arrangements, that would have been made between independent enterprises at the time of the transaction, considering the guidance in paragraph 6.185. Depending on the facts and circumstances of the case and considering the guidance in Section B.5 of Chapter III, a multi-year analysis of the information for the application of this approach may be appropriate ...

In response to the considerations discussed above, this section contains an approach consistent with the arm’s length principle that tax administrations can adopt to ensure that tax administrations can determine in which situations the pricing arrangements as set by the taxpayers are at arm’s length and are based on an appropriate weighting of the foreseeable developments or events that are relevant for the valuation of certain hard-to-value intangibles, and in which situations this is not the case. Under this approach, ex post evidence provides presumptive evidence as to the existence of uncertainties at the time of the transaction, whether the taxpayer appropriately took into account reasonably foreseeable developments or events at the time of the transaction, and the reliability of the information used ex ante in determining the transfer price for the transfer of such intangibles or rights in intangibles. Such presumptive evidence may be subject to rebuttal as stated in paragraphs 6.193 and 6.194, if it can be demonstrated that it does not affect the accurate determination of the arm’s length price. This situation should be distinguished from the situation in which hindsight is used by taking ex post results for tax assessment purposes without considering whether the information on which the ex post results are based could or should reasonably have been known and considered by the associated enterprises at the time the transaction was entered into ...