Best method rule

(c)Best method rule—(1) In general. The arm's length result of a controlled transaction must be determined under the method that, under the facts and circumstances, provides the most reliable measure of an arm's length result. Thus, there is no strict priority of methods, and no method will invariably be considered to be more reliable than others. An arm's length result may be determined under any method without establishing the inapplicability of another method, but if another method subsequently is shown to produce a more reliable measure of an arm's length result, such other method must be used. Similarly, if two or more applications of a single method provide inconsistent results, the arm's length result must be determined under the application that, under the facts and circumstances, provides the most reliable measure of an arm's length result. See § 1.482-8 for examples of the application of the best method rule. See § 1.482-7 for the applicable methods in the case of a cost sharing arrangement.

(2)Determining the best method. Data based on the results of transactions between unrelated parties provides the most objective basis for determining whether the results of a controlled transaction are arm's length. Thus, in determining which of two or more available methods (or applications of a single method) provides the most reliable measure of an arm's length result, the two primary factors to take into account are the degree of comparability between the controlled transaction (or taxpayer) and any uncontrolled comparables, and the quality of the data and assumptions used in the analysis. In addition, in certain circumstances, it also may be relevant to consider whether the results of an analysis are consistent with the results of an analysis under another method. These factors are explained in paragraphs (c)(2)(i), (ii), and (iii) of this section.

(i)Comparability. The relative reliability of a method based on the results of transactions between unrelated parties depends on the degree of comparability between the controlled transaction or taxpayers and the uncontrolled comparables, taking into account the factors described in § 1.482-1(d)(3) (Factors for determining comparability), and after making adjustments for differences, as described in § 1.482-1(d)(2) (Standard of comparability). As the degree of comparability increases, the number and extent of potential differences that could render the analysis inaccurate is reduced. In addition, if adjustments are made to increase the degree of comparability, the number, magnitude, and reliability of those adjustments will affect the reliability of the results of the analysis. Thus, an analysis under the comparable uncontrolled price method will generally be more reliable than analyses obtained under other methods if the analysis is based on closely comparable uncontrolled transactions, because such an analysis can be expected to achieve a higher degree of comparability and be susceptible to fewer differences than analyses under other methods. See § 1.482-3(b)(2)(ii)(A). An analysis will be relatively less reliable, however, as the uncontrolled transactions become less comparable to the controlled transaction.

(ii)Data and assumptions. Whether a method provides the most reliable measure of an arm's length result also depends upon the completeness and accuracy of the underlying data, the reliability of the assumptions, and the sensitivity of the results to possible deficiencies in the data and assumptions. Such factors are particularly relevant in evaluating the degree of comparability between the controlled and uncontrolled transactions. These factors are discussed in paragraphs (c)(2)(ii) (A), (B), and (C) of this section.

(A)Completeness and accuracy of data. The completeness and accuracy of the data affects the ability to identify and quantify those factors that would affect the result under any particular method. For example, the completeness and accuracy of data will determine the extent to which it is possible to identify differences between the controlled and uncontrolled transactions, and the reliability of adjustments that are made to account for such differences. An analysis will be relatively more reliable as the completeness and accuracy of the data increases.

(B)Reliability of assumptions. All methods rely on certain assumptions. The reliability of the results derived from a method depends on the soundness of such assumptions. Some assumptions are relatively reliable. For example, adjustments for differences in payment terms between controlled and uncontrolled transactions may be based on the assumption that at arm's length such differences would lead to price differences that reflect the time value of money. Although selection of the appropriate interest rate to use in making such adjustments involves some judgement, the economic analysis on which the assumption is based is relatively sound. Other assumptions may be less reliable. For example, the residual profit split method may be based on the assumption that capitalized intangible development expenses reflect the relative value of the intangible property contributed by each party. Because the costs of developing an intangible may not be related to its market value, the soundness of this assumption will affect the reliability of the results derived from this method.

(C)Sensitivity of results to deficiencies in data and assumptions. Deficiencies in the data used or assumptions made may have a greater effect on some methods than others. In particular, the reliability of some methods is heavily dependent on the similarity of property or services involved in the controlled and uncontrolled transaction. For certain other methods, such as the resale price method, the analysis of the extent to which controlled and uncontrolled taxpayers undertake the same or similar functions, employ similar resources, and bear similar risks is particularly important. Finally, under other methods, such as the profit split method, defining the relevant business activity and appropriate allocation of costs, income, and assets may be of particular importance. Therefore, a difference between the controlled and uncontrolled transactions for which an accurate adjustment cannot be made may have a greater effect on the reliability of the results derived under one method than the results derived under another method. For example, differences in management efficiency may have a greater effect on a comparable profits method analysis than on a comparable uncontrolled price method analysis, while differences in product characteristics will ordinarily have a greater effect on a comparable uncontrolled price method analysis than on a comparable profits method analysis.

(iii)Confirmation of results by another method. If two or more methods produce inconsistent results, the best method rule will be applied to select the method that provides the most reliable measure of an arm's length result. If the best method rule does not clearly indicate which method should be selected, an additional factor that may be taken into account in selecting a method is whether any of the competing methods produce results that are consistent with the results obtained from the appropriate application of another method. Further, in evaluating different applications of the same method, the fact that a second method (or another application of the first method) produces results that are consistent with one of the competing applications may be taken into account.