TREASURY REGULATIONS

(a) Tax based on price. Except as provided in paragraph (d) of this section, tax liability incurred on the use of an article shall be computed on the price at which such or similar articles are sold in the ordinary course of trade by manufacturers, producers, or importers thereof and in the absence of special arrangements. For additional provisions applicable in computing the tax in the case of the use of an article by a manufacturer and producer who purchased the article free of tax under section 4221(a)(1) for use by him in further manufacture, see section 423(b) and the regulations thereunder.

(b) Articles regularly sold by manufacturer. If the manufacturer, producer, or importer of an article regularly sells such articles at wholesale in arm's length transactions, tax liability on his use of any such article shall be computed on his lowest established wholesale price for such articles in effect at the time of the taxable use. In establishing such price, there shall be included and excluded, as applicable, the charges and readjustments specified in sections 4216(a), 4216(f), and 6416(b)(1), as in effect at the time tax liability on the use of the article is incurred, and the regulations thereunder contained in this subpart and subpart O. If the manufacturer, producer, or importer of an article does not regularly sell such articles at wholesale in arm's length transactions, a constructive price on which the use tax shall be computed will be determined by the Commissioner. This price will be established after considering the selling practices and price structures of manufacturers, producers, and importers of similar articles.

(c) Articles governed by section 4218(a) used in manufacture of nontaxable combination articles. If the manufacturer, producer, or importer of an article to which section 4218(a) applies does not regularly sell such article separately but uses it as material in the manufacture or production of, or as a component part of, a nontaxable combination article consisting of a taxable and nontaxable article, liability for tax on his use shall be computed on the constructive price of the taxable article at the time of use. To determine the constructive price of the taxable article in such case, the combination article is considered to be composed of (1) parts used exclusively in the functioning of the taxable article in the combination, (2) parts used exclusively in the functioning of the nontaxable article in the combination, and (3) parts, called common parts, which serve a dual function in connection with the parts in both subparagraphs (1) and (2) of this paragraph. The ratio which the cost of the parts in subparagraph (1) of this paragraph bears to the sum of the cost of such parts and the parts in subparagraph (2) of this paragraph is applied to the lowest established wholesale price for which like combination articles are at the time of the taxable use being sold by the manufacturer or producer in the ordinary course of trade. The resulting amount is the constructive sale price for the taxable article on which tax is to be computed. The cost of the common parts is allocable to the parts in subparagraphs (1) and (2) of this paragraph in the same ratio, and, therefore, need not be taken into account in the computation since the inclusion and allocation of the cost of such parts in the determination would not result in a different ratio. In determining the lowest established wholesale price for the combination article, there shall be included and excluded, as applicable, the charges and readjustments specified in sections 4216(a), 4216(f), and 6416(b)(1), as in effect at the time tax liability on the use of the taxable article is incurred, and the regulations thereunder contained in this subpart and subpart O of this part. The tax applicable to the use of the article for which a constructive sale price has been computed is not affected by any charges or readjustments of the price for which the nontaxable combination article is sold, whether by reason of the return or repossession of the nontaxable article or its covering or container, or by a bona fide discount, rebate, allowance, or other factor. The application of this subparagraph may be illustrated by the following example:

(d) Tax based on weight or volume. Where liability for tax is incurred on the use of an article subject, if sold, to a tax based on:

(1) The weight of the article (such as a tire), or

(2) The volume of the article (such as gasoline or lubricating oil),