CFA Level 1 Inventory Analysis: FIFO, LIFO, Write-Downs & Inventory Ratios
Inventory Cost Flow Methods
The fundamental question: when a company sells inventory, which costs get assigned to cost of goods sold (COGS) on the income statement, and which costs stay on the balance sheet as ending inventory? The answer depends on the cost flow method used.
| Method | How It Works | GAAP Availability |
|---|---|---|
| First-In, First-Out (FIFO) | Oldest costs go to COGS first. Ending inventory reflects the most recent purchase prices. | Permitted under both IFRS and US GAAP |
| Last-In, First-Out (LIFO) | Newest costs go to COGS first. Ending inventory reflects the oldest (and often lowest) purchase prices. | US GAAP only — IFRS prohibits LIFO |
| Weighted Average Cost | COGS and ending inventory both reflect the weighted average of all units available for sale during the period. | Permitted under both IFRS and US GAAP |
| Specific Identification | Each item’s actual cost is tracked and assigned. Used for unique, high-value items (jewelry, real estate, custom goods). | Permitted under both IFRS and US GAAP |
FIFO vs. LIFO vs. Weighted Average: Impact on Financials
The choice of inventory method affects nearly every financial statement and ratio. Here’s the full picture during a period of rising prices (the typical exam scenario) with stable or growing inventory quantities:
| Financial Item | FIFO | LIFO |
|---|---|---|
| Cost of Goods Sold | Lower (older, cheaper costs) | Higher (newer, more expensive costs) |
| Gross Profit | Higher | Lower |
| Net Income | Higher | Lower |
| Income Tax Expense | Higher (more taxable income) | Lower (tax advantage — a key reason firms use LIFO) |
| Ending Inventory (balance sheet) | Higher (closer to current replacement cost) | Lower (reflects old, stale costs) |
| Cash Flow from Operations | Lower (higher taxes paid) | Higher (lower taxes paid) |
| Gross Profit Margin | Higher | Lower but more stable over time |
| Inventory Turnover | Lower (larger ending inventory in denominator) | Higher (smaller ending inventory) |
| Current Ratio | Higher (larger inventory in current assets) | Lower |
| Debt-to-Equity | Lower (higher retained earnings) | Higher (lower retained earnings) |
The LIFO Reserve: Converting LIFO to FIFO
US GAAP requires companies using LIFO to disclose the LIFO reserve — the difference between inventory reported under LIFO and what it would be under FIFO. This disclosure is essential for analysts comparing LIFO companies to FIFO or IFRS companies.
How to Adjust LIFO Financial Statements to a FIFO Basis
| Adjustment | Formula | Why |
|---|---|---|
| Inventory (balance sheet) | FIFO Inventory = LIFO Inventory + LIFO Reserve | Restates inventory to approximate current replacement cost |
| COGS (income statement) | FIFO COGS = LIFO COGS − Change in LIFO Reserve | If LIFO reserve grew, LIFO COGS was higher than FIFO COGS by that amount |
| Retained earnings (equity) | Add LIFO Reserve × (1 − Tax Rate) | After-tax effect of cumulative COGS difference |
| Deferred tax liability | Increase by LIFO Reserve × Tax Rate | Higher FIFO inventory creates a temporary difference — taxes deferred under LIFO will eventually be owed |
LIFO Liquidation
LIFO liquidation occurs when a LIFO company sells more units than it purchases, dipping into old, low-cost inventory layers. This creates artificially high gross margins because old, cheap costs are matched against current revenue.
| Effect of LIFO Liquidation | Impact |
|---|---|
| COGS | Decreases (old, cheap costs flow to income statement) |
| Gross profit & net income | Artificially inflated — not sustainable |
| Tax expense | Increases (higher taxable income), eliminating the LIFO tax benefit |
| LIFO reserve | Decreases |
| Cash flow | Earnings boost not supported by cash flow — higher taxes are real cash outflows |
Inventory Write-Downs: IFRS vs. US GAAP
When inventory’s value falls below its carrying amount, a write-down is required. The rules differ significantly between IFRS and US GAAP.
| Feature | IFRS | US GAAP |
|---|---|---|
| Valuation basis | Lower of cost and net realizable value (NRV) | Lower of cost and NRV for FIFO/weighted average; lower of cost or market for LIFO and retail methods |
| Net realizable value | Estimated selling price − costs to complete and sell | Same definition |
| “Market” (LIFO only) | N/A (LIFO not permitted) | Current replacement cost, subject to ceiling (NRV) and floor (NRV − normal profit margin) |
| Reversal of write-down | Required if value recovers (limited to original write-down amount) | Prohibited — once written down, the new lower cost is permanent |
| Income statement impact | Write-down increases COGS (or reported separately); reversal decreases COGS | Write-down increases COGS; no reversal |
Impact of Write-Downs on Ratios
| Ratio | Effect of Write-Down | Why |
|---|---|---|
| Profitability (gross margin, net margin) | Decreases | Higher COGS reduces profit |
| Liquidity (current ratio) | Decreases | Lower inventory reduces current assets |
| Solvency (debt-to-equity) | Increases (worse) | Lower equity from reduced net income |
| Activity (inventory turnover) | Increases (looks better) | Lower inventory in the denominator |
Inventory Ratios
Three key ratios for evaluating inventory management:
Interpreting Inventory Ratios
| Signal | Possible Positive Explanation | Possible Negative Explanation |
|---|---|---|
| High turnover / low DOH | Efficient inventory management, strong demand | Inadequate inventory levels leading to stockouts; recent write-downs reducing the denominator |
| Low turnover / high DOH | Seasonal buildup, preparing for large orders | Slow-moving or obsolete inventory; declining demand |
| Inventory growing faster than sales | Stocking up for anticipated demand | Potential obsolescence; possible earnings manipulation (understated write-downs) |
Always compare inventory ratios to industry peers and examine trends over time. A company’s inventory method (FIFO vs. LIFO) directly affects these ratios, so adjust for method differences before making cross-company comparisons.
Inventory Disclosure Requirements
Both IFRS and US GAAP require disclosure of the following: accounting policy used, total carrying amount by classification (raw materials, work-in-progress, finished goods), amounts recognized as expense (COGS), and write-down amounts. IFRS additionally requires disclosure of write-down reversals and the circumstances behind them. US GAAP requires disclosure of material income from LIFO liquidation.
Connecting Inventory Analysis to the Broader Curriculum
| Concept | Where It Connects |
|---|---|
| FIFO/LIFO effects on taxes | Income Taxes — deferred tax liabilities from LIFO reserve |
| Inventory as a warning sign | Financial Reporting Quality — inventory growth vs. sales growth, obsolescence reserves |
| Days of inventory on hand | Working Capital Management — cash conversion cycle (DOH + DSO − DPO) |
| Inventory on the balance sheet | Financial Reporting — current assets, common-size analysis |
| Capitalization vs. expensing | Long-Lived Assets — similar concepts apply to asset recognition decisions |
Study Strategy for Inventory Analysis
- Master the FIFO vs. LIFO effects table. Know every line for rising prices, and be ready to reverse them for falling prices. This is the #1 testable concept.
- Practice LIFO reserve adjustments. Work through converting a LIFO company to FIFO basis — adjust inventory, COGS, retained earnings, and deferred tax. These are multi-step calculation questions.
- Know the IFRS vs. US GAAP write-down differences. IFRS allows reversals, US GAAP doesn’t. LIFO creates a different “market” floor/ceiling test. This is a favorite comparison question.
- Understand LIFO liquidation. Know that it inflates margins artificially, is disclosed by US GAAP, and should be treated as non-recurring.
- Link inventory ratios to real-world signals. The exam doesn’t just ask you to calculate ratios — it asks what they mean. Practice interpreting high/low turnover in context.
For all formulas in one place, see the CFA Level 1 Formula Sheet. For practice across all topics, visit Practice Questions.
Key Takeaways
- During rising prices: FIFO → higher income, higher inventory, higher taxes, lower cash flow. LIFO → the opposite. Weighted average falls between.
- IFRS prohibits LIFO — one of the most important IFRS vs. US GAAP differences on the exam.
- The LIFO reserve = FIFO Inventory − LIFO Inventory. Use it to convert LIFO financials to a FIFO basis for cross-company comparison.
- LIFO liquidation occurs when sales exceed purchases, dipping into old low-cost layers — it inflates margins artificially and is a reporting quality red flag.
- IFRS measures inventory at lower of cost and NRV, and requires reversal of write-downs if value recovers. US GAAP prohibits write-down reversals.
- Inventory write-downs hurt profitability and solvency ratios but improve activity ratios (lower denominator).
- Always compare inventory ratios to industry peers and adjust for method differences before drawing conclusions.
- Inventory growing faster than sales — without a clear operational explanation — is a warning sign for obsolescence or potential manipulation.
Frequently Asked Questions
Why do US companies use LIFO if it results in lower reported income?
The primary reason is taxes. During periods of rising prices, LIFO assigns higher costs to COGS, which reduces taxable income and generates real cash savings through lower tax payments. The US tax code requires the “LIFO conformity rule” — if a company uses LIFO for tax purposes, it must also use LIFO for financial reporting. The tax savings from LIFO often outweigh the hit to reported earnings, especially for companies with investors who focus on cash flow rather than accounting income.
How does the LIFO reserve help analysts compare companies?
The LIFO reserve measures the cumulative difference between LIFO inventory and what inventory would be under FIFO. By adding the LIFO reserve to the reported inventory balance, an analyst can approximate what the company’s inventory would be on a FIFO basis. Similarly, the change in LIFO reserve during a period approximates the difference between LIFO and FIFO cost of goods sold. This makes cross-company comparisons meaningful, especially when comparing a US LIFO company to an IFRS peer that must use FIFO or weighted average.
What is LIFO liquidation and why should analysts care?
LIFO liquidation happens when a company using LIFO sells more inventory than it buys, causing old, lower-cost inventory layers to be charged to cost of goods sold. This reduces COGS and inflates gross profit, but the effect is temporary and non-recurring. It also triggers higher tax payments, erasing the tax benefit of LIFO. Analysts should treat the resulting margin improvement as unsustainable and adjust earnings accordingly.
Can a company reverse an inventory write-down under IFRS?
Yes, IFRS requires reversal of a previous write-down if the net realizable value subsequently increases. The reversal is limited to the original write-down amount — you can’t write inventory above its original cost. The reversal is recognized as a reduction in cost of goods sold. US GAAP does not allow reversals of inventory write-downs under any circumstances.
How do inventory methods affect the cash conversion cycle?
Inventory methods affect the days of inventory on hand (DOH) component of the cash conversion cycle. LIFO typically shows lower ending inventory (during inflation), producing higher turnover and lower DOH — making the cash conversion cycle appear shorter. But this is an accounting artifact, not a real efficiency gain. When comparing cash conversion cycles across companies using different methods, adjust inventory to a common basis using the LIFO reserve before calculating DOH.
What’s the difference between NRV and “market” for inventory write-downs?
Net realizable value (NRV) is the estimated selling price minus costs to complete and sell — used by IFRS and by US GAAP for FIFO/weighted average methods. “Market” under US GAAP (used for LIFO and retail methods) is current replacement cost, but bounded by a ceiling (NRV) and a floor (NRV minus a normal profit margin). The “market” test can produce a different write-down amount than the NRV test because of the floor constraint.