Inventory accounting is the practice of valuing the goods a business holds and recording them as an asset until they are sold, at which point their cost moves to cost of goods sold, the charge set against that period’s revenue. The goods it covers are items of tangible personal property held for sale in the ordinary course of business, in process of production for such sale, or to be currently consumed in the production of goods or services to be available for sale (Accounting Research Bulletin No. 43, Chapter 4, Statement 1). Two separate bodies of rules then run on that same stock, because US GAAP decides what the financial statements carry and federal tax law decides what the return reports.
The three limbs of that definition are the classes a manufacturer holds, raw materials, work in progress and finished goods. A business that only buys and resells carries goods held for sale alone, what the standard’s discussion calls the merchandise of a trading concern (Accounting Research Bulletin No. 43, Chapter 4, Discussion paragraph 3).
Two Authorities, One Set of Goods
The financial reporting rules and the tax rules are separate tests applied to the same shelf, not one rule stated twice, which is why a client can correctly carry one figure in the accounts and a different one on the return.
The reporting side sits in the inventory topic of the FASB Accounting Standards Codification, Topic 330 (FASB Accounting Standards Update 2015-11, Inventory (Topic 330)). The primary basis of accounting for inventories is cost (Accounting Research Bulletin No. 43, Chapter 4, Statement 3), and what the goods are carried at after that depends on which cost method the business runs, a split set out in net realizable value. Damage, deterioration and obsolescence push goods below cost and produce a write-down, which changes the carrying amount rather than the quantity.
The tax side starts from a different question, whether inventories are needed to show the income clearly in the first place. Whenever in the opinion of the Secretary the use of inventories is necessary in order clearly to determine the income of any taxpayer, inventories shall be taken by such taxpayer on such basis as the Secretary may prescribe as conforming as nearly as may be to the best accounting practice in the trade or business and as most clearly reflecting the income (26 U.S.C. 471(a)). The regulation makes that concrete, and except as provided for certain small business taxpayers, in order to reflect taxable income correctly, inventories at the beginning and end of each taxable year are necessary in every case in which the production, purchase, or sale of merchandise is an income-producing factor (26 CFR 1.471-1(a)).
A second tax rule then loads the figure. Where section 263A applies, the direct costs of the property and its proper share of allocable indirect costs, including taxes, are included in inventory costs where the property is inventory in the taxpayer’s hands, and capitalized where it is not (26 U.S.C. 263A(a)). That is uniform capitalization, usually shortened to UNICAP, and it applies to real or tangible personal property produced by the taxpayer and to property acquired by the taxpayer for resale (26 U.S.C. 263A(b)).
Both tax rules carry the same exit. A taxpayer that meets the gross receipts test of section 448(c), and that is not a tax shelter barred from the cash receipts and disbursements method of accounting under section 448(a)(3), is outside section 471(a) (26 U.S.C. 471(c)(1)) and outside section 263A (26 U.S.C. 263A(i)(1)).
For taxable years beginning in 2026, a corporation or partnership meets that gross receipts test if its average annual gross receipts for the three-taxable-year period ending with the taxable year preceding it do not exceed $32,000,000 (IRS, Rev. Proc. 2025-32, section 4.30).
Taking the exit is not the same as having nothing to do. A qualifying taxpayer’s method of accounting for inventory is not treated as failing to clearly reflect income if it either treats inventory as non-incidental materials and supplies, or conforms to the method reflected in the taxpayer’s applicable financial statement or, where there is no such statement, to the books and records prepared under the taxpayer’s own accounting procedures (26 U.S.C. 471(c)(1)(B)). Applicable financial statement is a defined term there rather than a loose description, and it takes its meaning from section 451(b)(3) (26 U.S.C. 471(c)(2)).
How the Cost Reaches Cost of Goods Sold
The mechanism is one subtraction. Opening inventory plus the year’s additions, less closing inventory, is the cost of what was sold, and an entity filing Form 1120, 1120-C, 1120-F, 1120S, or 1065 performs that arithmetic on Form 1125-A (IRS, Form 1125-A, Rev. November 2024), whose lines are walked in raw materials.
That form is also where the two sets of rules meet on one page. It carries a separate line where a taxpayer that elected a simplified method enters the balance of section 263A costs paid or incurred during the tax year not includible on the purchases, cost of labor and other costs lines, and it asks outright whether the rules of that section apply to the entity, so the tax layer is settled on the return rather than assumed to be sitting in the book figure already (IRS, Form 1125-A, Rev. November 2024).
Say a distributor client that has elected a simplified method produces the figures below, with the balance of its section 263A costs not includible on the purchases line added on the return.
Inventory at beginning of year $180,000
Purchases $940,000
Additional section 263A costs $26,000
Total $1,146,000
Inventory at end of year $211,000
Cost of goods sold 1,146,000 - 211,000 $935,000The closing balance is where both authorities land. Whatever the reporting rule says the goods are carried at, and whatever the tax rules say has to be capitalized into them, arrives as one figure on that line, and cost of goods sold is whatever the subtraction leaves. Ratios built on the same balance, inventory turnover and days inventory outstanding, inherit it too.
Periodic and Perpetual Systems
The choice is about when the ledger moves, not about what it eventually says. A periodic system leaves the inventory account untouched through the year and rebuilds it from a count at the close, so the subtraction above is the only route to cost of goods sold. A perpetual system posts each receipt and each withdrawal as it happens and carries a running balance, so the closing figure already exists before anyone walks the warehouse.
Neither system retires the count. What federal tax law requires of counting, what a count exposes against the records, and the estimating relief allowed between counts are set out in shrinkage.
Whose Goods Are They at the Close
Possession does not settle it. Merchandise should be included in the inventory only if title thereto is vested in the taxpayer (26 CFR 1.471-1(a)). A purchaser should include merchandise it has taken title to even where the goods are in transit or have for other reasons not been reduced to physical possession, and should exclude goods ordered for future delivery where title has not yet passed. A seller should include goods under contract for sale but not yet segregated and applied to the contract, and goods out upon consignment, and should exclude goods sold whose title has passed to the purchaser (26 CFR 1.471-1(a)).
That is why the delivery term on the purchase order reaches the balance sheet. Whether title passes at the seller’s dock or at the buyer’s, which is the practical content of FOB shipping point and FOB destination, decides whose closing inventory a container still at sea belongs in. Getting it wrong is a named defect rather than a judgment call, because including stock in transit, shipped either to or from the taxpayer, the title to which is not vested in the taxpayer, is listed among the methods that are not in accord with the regulations (26 CFR 1.471-2(f)(5)).
What Inventory Accounting Is Commonly Confused With
It is not the cost flow assumption. First-in first-out, last-in first-out and average cost each answer one narrow question, which recorded costs move to expense when goods sell, and they are set out in FIFO, LIFO and LIFO vs FIFO. Inventory accounting is the wider practice those assumptions sit inside, and a business still has to settle what is in the count, which costs attach to a unit and what the goods are carried at.
It is not cost accounting either, though the two share a border. Cost accounting works out what a unit costs to make. Inventory accounting decides which of those costs wait on the balance sheet inside a unit and which the current period reports outright, a split set out in period vs product cost.
Common Questions
The recording is not. The subtraction is one line and most accounting software posts the entries. What makes the engagement hard is everything sitting around the arithmetic: the closing balance rests on a count and a clean cutoff, the same goods are measured under a reporting rule and a tax rule that do not have to agree, and a client whose gross receipts move past the section 448(c) test loses both tax exemptions at once.
The job is the closing balance and everything feeding it. That means costing receipts and production into the right class, reconciling the perpetual ledger to the physical count, chasing down the differences, applying the measurement rule at the close, and producing schedules that support the inventory line for both the auditor and the return preparer.
Accountably places trained offshore accountants inside US CPA and EA firms, and a firm can put a block of its own inventory reconciliation and close work through a trial task before anything client facing depends on it.
