Scope

ASC 330 governs the accounting for inventory — the assets held for sale in the ordinary course of business, in the process of production for such sale, or to be currently consumed in the production of goods or services to be available for sale.

The standard applies broadly across industries — retail, distribution, manufacturing, restaurant operations, oil and gas, software (for unsold copies on physical media), and any other entity holding goods for sale. Service industries with no physical inventory and entities accounting for inventory under specialized guidance (regulated utilities, certain commodity broker-dealers, some agricultural producers) are partial exceptions.

The inventory line item is frequently among the largest and most judgmental balances on the balance sheet for manufacturers and distributors. The accounting mechanics are straightforward; the judgment lies in valuation, capitalization decisions, and reserves.

Cost flow assumptions

US GAAP permits multiple cost flow assumptions:

First-in, first-out (FIFO) — oldest costs flow to COGS first; ending inventory carries the most recent costs.
Last-in, first-out (LIFO) — most recent costs flow to COGS first; ending inventory carries older costs (potentially many years old in "LIFO layers"). Prohibited under IFRS.
Weighted-average cost — costs are averaged across all units available for sale.
Specific identification — used for high-value or unique items where individual costs can be tracked.
Retail inventory method — used by retailers; cost-to-retail ratios applied to ending retail inventory.

The cost flow assumption is a policy election and must be applied consistently. Changes in cost flow assumption are accounting changes under ASC 250, requiring retrospective application except in specific cases (LIFO to FIFO transitions are typically prospective with disclosure).

LIFO considerations:

LIFO is permitted under US GAAP but prohibited under IFRS — a US parent with non-US subsidiaries must convert subsidiary inventory to FIFO or weighted-average for IFRS local statutory reporting.
The LIFO conformity rule (IRC § 472(c)) requires that an entity using LIFO for federal income tax also use LIFO for financial reporting. The conformity is to the primary financial statements; supplementary disclosure of non-LIFO equivalents is permitted.
During periods of rising prices, LIFO results in higher COGS and lower taxable income relative to FIFO — providing a tax deferral benefit that companies cite as the primary reason for the election.
LIFO liquidation — when LIFO inventory quantities decline, older LIFO layers with potentially low historical costs flow through COGS, producing an artificial boost to gross margin. Material LIFO liquidations are disclosed.

Inventory cost components

The cost of inventory includes all costs incurred to bring the inventory to its present location and condition. For manufacturers, this means:

Direct materials — raw materials consumed in production
Direct labor — labor directly applied to production
Manufacturing overhead — indirect production costs allocated to inventory (factory rent, utilities, depreciation of factory equipment, factory supervision, quality control)

Selling and administrative costs are not capitalized into inventory — they're period expenses. Idle facility expense, abnormal freight and handling costs, and abnormal spoilage are also typically expensed rather than capitalized.

Under ASC 330-10-30-2 through 30-8, fixed production overhead is allocated based on normal capacity — the production expected to be achieved on average over a number of periods under normal circumstances. Underutilization (when actual production is below normal capacity) results in fixed overhead being expensed rather than fully absorbed into inventory.

UNICAP for tax purposes — IRC § 263A requires additional capitalization of certain costs into inventory for tax purposes that may not be capitalized for book. The book/tax difference is a temporary difference under ASC 740.

Lower of cost and net realizable value (LCNRV)

ASC 330-10-35 (post ASU 2015-11) requires inventory to be measured at the lower of cost and net realizable value (NRV) — except for inventory measured using LIFO or the retail inventory method, which continues to use the lower of cost or market (LCM).

Net realizable value = Estimated selling price in the ordinary course of business, minus reasonably predictable costs of completion, disposal, and transportation.

The LCNRV test is applied at the appropriate unit of measurement (individual item, category, or total inventory, depending on circumstances). When NRV is less than cost, the inventory is written down to NRV through COGS or a separate loss line. The write-down establishes a new cost basis — subsequent recoveries cannot be recognized.

LIFO/Retail method LCM test:

For LIFO and retail-method inventory, "market" is the current replacement cost, subject to a ceiling (NRV) and a floor (NRV minus a normal profit margin).

Inventory reserves and write-downs

Beyond the LCNRV test, companies typically establish reserves for specific inventory categories:

Excess and obsolete (E&O) reserve — for inventory that exists in quantities greater than expected future demand, or that has become obsolete due to product transitions, technology changes, or end-of-life decisions.
Slow-moving inventory reserve — for inventory with no recent movement or anticipated demand within a defined horizon.
Lower of cost or market reserve — for inventory where market price has declined below carrying cost.
Scrap and rework reserve — for inventory expected to be scrapped or reworked.

Reserve methodologies are typically formula-based — tied to demand forecasts, days of inventory on hand, or age of inventory — with overlays for known-obsolete items. The methodology must be documented, applied consistently, and refreshed for changes in business conditions.

Disclosure requirements

Description of the cost flow assumption (FIFO, LIFO, weighted-average, etc.)
Major classes of inventory (raw materials, work in process, finished goods, supplies)
LIFO reserve and the difference between LIFO and FIFO/replacement cost (for LIFO inventory)
Significant inventory write-downs
Any unusual losses from market declines

Common pitfalls

Overhead allocation based on actual rather than normal capacity. During periods of below-normal production, allocating actual fixed overhead to actual production inflates per-unit cost and overstates inventory. The standard requires normal-capacity-based allocation.
Selling costs capitalized into inventory. Selling costs are period expenses, not inventoriable. The line between "manufacturing overhead" and "selling cost" is sometimes blurred (sales-incentive accruals tied to product launch, packaging for retail display, point-of-sale displays). Misclassification capitalizes period costs and overstates margins.
LIFO conformity violation. Using LIFO for tax but FIFO or weighted-average for financial reporting violates IRC § 472(c) and can trigger forced LIFO conformity for tax purposes, with retroactive effect.
E&O reserve methodology drift. A reserve formula that hasn't been recalibrated as product mix or business conditions changed often produces over- or under-reserves. Periodic review and benchmarking against actual scrap/disposal experience is essential.
LCNRV applied at the wrong unit of measure. Aggregating dissimilar inventory categories washes out the write-down at the category that's actually impaired. Apply LCNRV at the lowest reasonable unit of measure.
Failure to write down at quarter-end. Inventory write-downs should be recognized as conditions become known, not deferred to year-end. Material write-downs at year-end that should have been recognized earlier produce restatement risk.
Inventory in transit. FOB shipping point inventory is the buyer's inventory once shipped; FOB destination remains the seller's until received. Cutoff errors at period-end can move inventory between balance sheets incorrectly.

Operator note

The single largest fingerprint I left on Intersil's external financial statements was the inventory footnote. As Group Controller from 2005–2009 (five years, not three — the memory record had this wrong until recently), I owned the corporate inventory reserve and the COGS analytics for a $700M+ semiconductor manufacturer — five product groups, thousands of part numbers, the full inventory pipeline from wafer Die through Work in Process to Finished Goods, US wafer front-end fabrication through Malaysia back-end assembly and test.

The stack I worked with was Oracle (primary system for inventory accounting, COGS, and standard cost), Cognos PowerPlay for analytics across 8 years, Access for the data layer between Oracle extracts and the reserve models, and Excel for the working papers and Big 4 audit support. SAP FI/CO/MM/PP/SD was the secondary system, brought in via acquisition. For Intersil-specific inventory and COGS context, the answer is always Oracle first.

A few things I learned writing those 10-K and 10-Q inventory footnotes and defending them through five years of audit cycles:

The standard cost system is the foundation. Every part number had a standard cost — material, labor, overhead — that drove the inventory balance and the variance analysis. The standards needed to be refreshed each year (annual standard cost rollover), with variance disposition policies that determined how purchase price variance, labor variance, and overhead variance flowed back to inventory at year-end. Get the standard cost system wrong and every downstream metric is wrong.

The E&O reserve was the largest single accounting estimate in the company. The methodology was demand-based — forecast months of supply by part number, with progressively higher reserve rates as the months of supply grew. The forecast came from Sales & Operations Planning; the reserve formula came from Finance; the disposition decisions (scrap vs. continued hold) came from Operations. The reserve was reviewed monthly with operations leadership and quarterly with the audit committee. Auditors tested it every quarter.

Inventory in transit between US wafer fab and Malaysia assembly was a constant complexity. Material moved between legal entities, across customs jurisdictions, with intercompany markups and FX impacts. The reconciliation between the US books, the Malaysia books, and the consolidated US GAAP statements was a meaningful close activity each month. The Malaysia plant's local statutory reporting was Malaysian GAAP (with IFRS convergence in progress through the period); the US consolidation was GAAP — temporary differences flowed through deferred taxes under ASC 740.

LIFO would have been wrong for the business. Intersil used standard cost / FIFO. LIFO is conceptually attractive for tax deferral in rising-cost environments, but semiconductor pricing was generally declining over the product lifecycle. LIFO would have penalized the financial statements without delivering the tax benefit. The cost flow assumption is a business decision, not a default.

Capacity utilization drove a large portion of the absorption variance. During the 2008–2009 downturn, wafer fab utilization dropped meaningfully. Under ASC 330's normal-capacity-based overhead allocation, the unabsorbed fixed overhead was expensed rather than capitalized — producing a meaningful hit to gross margin even when revenue and direct costs were proportional. Investors and analysts who didn't understand the mechanics asked why margins fell faster than revenue. The answer was always the same: fixed overhead absorption.

The Malaysia plant — which I managed remotely as part of the offshore plant finance responsibility — added another layer. Backend assembly and test operates with different cost structures than front-end wafer fab. The plant-level P&L, intercompany transfer pricing, and consolidation mechanics required tight coordination between US corporate finance and the Malaysia controllership team. I lived in Malaysia for portions of those years and managed remotely for the rest. The credential "lived it, managed it remotely, currently running an offshore operation" comes from this exact experience.

For consulting clients in manufacturing and distribution, the most common ASC 330 issue I see is reserve methodology that hasn't been refreshed. The formula was built five years ago by someone who is no longer at the company, the inputs (demand forecast, months of supply thresholds) haven't been recalibrated, and the actual scrap experience suggests the formula is now wrong. The fix is straightforward — pull the last 24 months of actual scrap by category, compare to what the reserve formula predicted, and adjust the formula accordingly. Companies that don't refresh routinely have either over- or under-reserve drift that the auditors find before the company does.

Related references

IAS 2 — Inventories (international counterpart; LIFO prohibited)
ASC 740 — Income Taxes (UNICAP book/tax differences, LIFO conformity)
ASC 360 — Property, Plant, and Equipment (factory assets that depreciate into inventory cost)
ASC 605 / 606 — Revenue (cutoff matching with inventory flow)
SEC Reporting (MD&A discussion of inventory levels and turnover)