Inventory on the balance sheet must reflect reality — when goods become obsolete, damaged, or simply worth less than their recorded cost, GAAP demands recognition of the loss immediately. Libby's Chapter 7 covers the Lower of Cost or Net Realizable Value rule, LIFO reserve adjustments, and how inventory impairments signal broader business problems before they hit earnings.
The conservatism principle in accounting requires that losses be recognized as soon as they are probable, while gains are not recognized until realized. For inventory, this produces the Lower of Cost or Net Realizable Value (LCNRV) rule: inventory must be reported at the lower of its historical cost or its net realizable value — the estimated selling price minus the estimated costs of completion and sale.
Net Realizable Value
NRV = Estimated Selling Price − Estimated Completion and Selling Costs
If NRV < carrying cost, the difference must be written down immediately as a loss.
A fashion retailer has $4,000,000 of fall-season merchandise at cost. With spring approaching, unsold fall inventory can only be cleared at steep discount. Estimated selling price for the remaining items: $2,800,000. Estimated selling costs: $200,000. NRV = $2,800,000 − $200,000 = $2,600,000. Since NRV ($2,600,000) < cost ($4,000,000), the inventory must be written down by $1,400,000. Journal entry: DR Inventory Write-Down Loss $1,400,000 / CR Inventory $1,400,000. The $1,400,000 hits the income statement immediately — it cannot be deferred.
Once inventory is written down to NRV, the new lower cost becomes the new carrying value. Unlike some impairments (goodwill can be tested upward periodically), inventory write-downs are permanent under U.S. GAAP: subsequent recovery of selling price does not allow a write-up. The one exception: under IFRS, inventory write-downs can be reversed if NRV later rises (to the original cost, not above). This GAAP/IFRS difference can affect comparability for multinational companies.
| Trigger | Industry Examples | Detection Signal on Balance Sheet |
|---|---|---|
| Technological obsolescence | Electronics, semiconductors, smartphones | Inventory turnover declining; write-downs in technology cost of revenues |
| Seasonal end-of-life | Fashion, holiday merchandise, perishable foods | Inventory spike before quarter-end reversing sharply after |
| Commodity price declines | Oil & gas (crude, refined products), metals, agricultural | Inventory value declining while quantity increases; LCM disclosures in footnotes |
| Supplier quality issues or recalls | Automotive, food & beverage, pharmaceuticals | Sudden, large one-period write-down; product recall announcement |
| Demand collapse | Any consumer-facing industry during recession | Inventory/revenue ratio spiking; days inventory outstanding rising sharply |
FIFO vs LIFO vs Weighted Average — Same Goods, Different Numbers
Scenario: 100 units @ $10 + 100 units @ $14 purchased · 150 units sold · Prices rising
Total cost of goods available for sale (both methods, same goods)
$2,400 — 200 units (100 @ $10 + 100 @ $14)
FIFO
First-In, First-Out
COGS
$1,700
Ending Inv.
$700
Gross Profit
$700
29% margin
Higher taxes
Old (cheap) units expensed → higher profit
Weighted Avg
Average Cost
COGS
$1,800
Ending Inv.
$600
Gross Profit
$600
25% margin
Moderate taxes
Blended average cost per unit
LIFO
Last-In, First-Out
COGS
$1,900
Ending Inv.
$500
Gross Profit
$500
21% margin
Lower taxes
New (expensive) units expensed → lower profit
The Trade-Off — Rising Price Environment
FIFO: Better-looking P&L
Higher gross profit, current-cost inventory on balance sheet — but higher tax bill.
LIFO: Real cash savings
Lower reported profit, stale inventory on balance sheet — but genuine tax deferral.
Figure 1.1 — Three methods, same goods, three different outcomes. Revenue from selling 150 units at $16 = $2,400. Total cost available = $2,400. The split between COGS and ending inventory is what changes.
U.S. GAAP permits LIFO (Last-In, First-Out) for inventory accounting, while IFRS bans it. In an inflationary environment, LIFO produces higher COGS (newer, more expensive units sold first) and lower ending inventory (older, cheaper units remain). This creates a balance sheet inventory balance that may be decades out of date and dramatically understated relative to replacement cost.
To enable comparability, LIFO companies must disclose the LIFO reserve — the difference between what inventory would be under FIFO and what it is under LIFO. Using the LIFO reserve, analysts can convert any LIFO-reporting company to a FIFO basis for comparison with FIFO or IFRS-reporting peers.
| Item | LIFO Reported | FIFO Adjustment | FIFO Equivalent |
|---|---|---|---|
| Ending Inventory (BS) | $320M | Add LIFO Reserve: +$95M | $415M |
| Pre-tax Income Adjustment | Increase in LIFO Reserve this year (say $15M) reduces FIFO COGS by $15M | FIFO Pre-tax Income = LIFO pre-tax + $15M | |
| Net Income (after 25% tax) | +$15M × (1 − 25%) = +$11.25M | FIFO Net Income = LIFO + $11.25M | |
| Retained Earnings (BS) | $890M | Add after-tax LIFO reserve: +$95M × 0.75 = +$71.25M | $961.25M |
LIFO liquidation occurs when a company sells more units than it purchases (drawing down inventory layers). When LIFO layers are liquidated, the very oldest (cheapest) costs flow into COGS — dramatically lowering reported COGS and inflating gross margin. This is not a genuine operating improvement — it's an accounting artifact of depleting old inventory layers. Detection: when a LIFO company's volume is declining but gross margin is expanding, check for LIFO liquidation disclosures in the footnotes. The IRS also requires companies that liquidate LIFO layers to recapture the tax benefit, which can create a substantial tax liability.
Inventory sitting on the balance sheet is cash that has been converted to goods but not yet to revenue. The longer inventory sits, the greater the risk: obsolescence, damage, price declines, and theft. Inventory turnover measures how efficiently a company converts its inventory investment into sales.
Inventory Turnover
Inventory Turnover = COGS ÷ Average Inventory
Higher is generally better — more sales generated per dollar of inventory investment.
Days Inventory Outstanding (DIO)
DIO = 365 ÷ Inventory Turnover (or Average Inventory ÷ Daily COGS)
Average number of days inventory sits before being sold. Lower is better for most businesses.
| Industry | Typical DIO Range | Key Driver |
|---|---|---|
| Grocery / Food Retail | 10–20 days | Perishable goods require rapid turnover |
| Fast Fashion Retail | 40–80 days | Seasonal collections; markdown risk high |
| Automobile Manufacturing | 30–60 days | Complex assembly; dealer inventory management |
| Pharmaceutical | 90–180 days | Regulatory holding requirements; complex supply chains |
| Aerospace / Defense | 180–365 days | Long production cycles; custom builds |
A mid-size retailer reports DIO of 65 days in Q1, 75 days in Q2, 90 days in Q3, and 110 days in Q4 — while revenue growth slows from 12% to 3%. This pattern preceded several major retail bankruptcies: inventory buildup signals that customers are not buying at the expected rate. The company must eventually markdown the excess inventory (LCNRV write-down) or accept lower gross margins to liquidate it. The rising DIO is a 6–9 month leading indicator of the markdown cycle.
The most complete inventory analysis combines four metrics: (1) DIO trend — is inventory turning slower? (2) Inventory-to-revenue ratio — is inventory growing faster than sales? (3) LIFO reserve size — for LIFO companies, how understated is balance sheet inventory? (4) Write-down history — has management already recognized losses, or are they still deferred? A company with rising DIO, a large and growing LIFO reserve, and no recent write-downs despite deteriorating market prices is deferring losses that will eventually appear.
Key Takeaways
A clothing retailer has winter coats with a cost of $800,000. Post-season, they can be sold for an estimated $500,000 (after $50,000 in selling costs). What is the required accounting treatment and its income statement effect?