(a) Section 471 provides two tests to which each inventory must conform:
(1) It must conform as nearly as may be to the best accounting practice in the trade or business, and
(2) It must clearly reflect the income.
(b) It follows, therefore, that inventory rules cannot be uniform but must give effect to trade customs which come within the scope of the best accounting practice in the particular trade or business. In order to clearly reflect income, the inventory practice of a taxpayer should be consistent from year to year, and greater weight is to be given to consistency than to any particular method of inventorying or basis of valuation so long as the method or basis used is in accord with Secs. 1.471-1 through 1.471-11.
(c) The bases of valuation most commonly used by business concerns and which meet the requirements of section 471 are (1) cost and (2) cost or market, whichever is lower. (For inventories by dealers in securities, see Sec. 1.471-5.) Any goods in an inventory which are unsalable at normal prices or unusable in the normal way because of damage, imperfections, shop wear, changes of style, odd or broken lots, or other similar causes, including second-hand goods taken in exchange, should be valued at bona fide selling prices less direct cost of disposition, whether subparagraph (1) or (2) of this paragraph is used, or if such goods consist of raw materials or partly finished goods held for use or consumption, they shall be valued upon a reasonable basis, taking into consideration the usability and the condition of the goods, but in no case shall such value be less than the scrap value. Bona fide selling price means actual offering of goods during a period ending not later than 30 days after inventory date. The burden of proof will rest upon the taxpayer to show that such exceptional goods as are valued upon such selling basis come within the classifications indicated above, and he shall maintain such records of the disposition of the goods as will enable a verification of the inventory to be made.
(d) In respect of normal goods, whichever method is adopted must be applied with reasonable consistency to the entire inventory of the taxpayer's trade or business except as to those goods inventoried under the last-in, first-out method authorized by section 472 or to animals inventoried under the elective unit, livestock-price-method authorized by Sec. 1.471-6. See paragraph (d) of Sec. 1.446-1 for rules permitting the use of different methods of accounting if the taxpayer has more than one trade or business. Where the taxpayer is engaged in more than one trade or business the Commissioner may require that the method of valuing inventories with respect to goods in one trade or business also be used with respect to similar goods in other trades or businesses if, in the opinion of the Commissioner, the use of such method with respect to such other goods is essential to a clear reflection of income. Taxpayers were given an option to adopt the basis of either (1) cost or (2) cost or market, whichever is lower, for their 1920 inventories. The basis properly adopted for that year or any subsequent year is controlling, and a change can now be made only after permission is secured from the Commissioner. Application for permission to change the basis of valuing inventories shall be made in writing and filed with the Commissioner as provided in paragraph (e) of Sec. 1.446-1. Goods taken in the inventory which have been so intermingled that they cannot be identified with specific invoices will be deemed to be the goods most recently purchased or produced, and the cost thereof will be the actual cost of the goods purchased or produced during the period in which the quantity of goods in the inventory has been acquired. But see section 472 as to last-in, first-out inventories. Where the taxpayer maintains book inventories in accordance with a sound accounting system in which the respective inventory accounts are charged with the actual cost of the goods purchased or produced and credited with the value of goods used, transferred, or sold, calculated upon the basis of the actual cost of the goods acquired during the taxable year (including the inventory at the beginning of the year), the net value as shown by such inventory accounts will be deemed to be the cost of the goods on hand. The balances shown by such book inventories should be verified by physical inventories at reasonable intervals and adjusted to conform therewith.
(e) Inventories should be recorded in a legible manner, properly computed and summarized, and should be preserved as a part of the accounting records of the taxpayer. The inventories of taxpayers on whatever basis taken will be subject to investigation by the district director, and the taxpayer must satisfy the district director of the correctness of the prices adopted.
(f) The following methods, among others, are sometimes used in taking or valuing inventories, but are not in accord with the regulations in this part:
(1) Deducting from the inventory a reserve for price changes, or an estimated depreciation in the value thereof.
(2) Taking work in process, or other parts of the inventory, at a nominal price or at less than its proper value.
(3) Omitting portions of the stock on hand.
(4) Using a constant price or nominal value for so-called normal quantity of materials or goods in stock.
(5) Including stock in transit, shipped either to or from the taxpayer, the title to which is not vested in the taxpayer.
(6) Segregating indirect production costs into fixed and variable production cost classifications (as defined in Sec. 1.471-11(b)(3)(ii)) and allocating only the variable costs to the cost of goods produced while treating fixed costs as period costs which are currently deductible. This method is commonly referred to as the ``direct cost'' method.
(7) Treating all or substantially all indirect production costs (whether classified as fixed or variable) as period costs which are currently deductible. This method is generally referred to as the ``prime cost'' method. [T.D. 6500, 25 FR 11724, Nov. 26, 1960, as amended by T.D. 7285, 38 FR 26185, Sept. 19, 1973]