Inventory Records For Dunbar Incorporated Revealed The Following

You stare at the spreadsheet. The numbers don't lie — but they don't exactly tell the whole truth either.

Inventory records for Dunbar Incorporated revealed the following: beginning inventory of 200 units at $12 each, a purchase of 300 units at $14 in March, another 250 units at $15 in July, and a final batch of 150 units at $16 in November. Now, sales totaled 700 units for the year. Now someone needs to figure out cost of goods sold and ending inventory value.

Sound familiar? If you've taken an accounting class or managed books for a product-based business, this exact scenario — or one uncomfortably close to it — has probably landed on your desk.

Here's the thing: the data itself is neutral. The method you choose to interpret it? That's where the story changes.

What Is Inventory Valuation (And Why Dunbar Incorporated Keeps Showing Up in Textbooks)

Inventory valuation is the process of assigning a dollar value to the goods a company has on hand at the end of an accounting period. It determines cost of goods sold (COGS) on the income statement and ending inventory on the balance sheet. Both numbers flow into tax returns, loan covenants, investor ratios, and — if you're unlucky — audit workpapers.

Dunbar Incorporated isn't a real company. And it's a teaching construct, the "John Doe" of intermediate accounting problems. Professors love it because the numbers are clean enough to calculate by hand but messy enough to expose whether a student actually understands the mechanics.

But the principles behind the Dunbar problem apply to every business that holds physical stock. Consider this: a hardware store in Ohio. Practically speaking, a manufacturer in Germany. Consider this: a dropshipper in Singapore. Consider this: the inventory records reveal the following: quantities, costs, dates. The accountant decides what happens next.

The Four Main Methods (And One That's Mostly Academic)

You'll see these five methods in every textbook. Three dominate real-world practice. That's why one is banned under IFRS. One is reserved for unique, high-value items.

FIFO (First-In, First-Out) assumes the oldest units sell first. Under Dunbar's data, the 200 units at $12 leave first, then the 300 at $14, then 200 of the 250 at $15. Ending inventory consists of the most recent purchases — 50 units at $15 and all 150 at $16. In rising-price environments, FIFO produces the lowest COGS, highest gross profit, and highest ending inventory value. It also tends to match the actual physical flow for perishable or time-sensitive goods.

LIFO (Last-In, First-Out) assumes the newest units sell first. The 150 units at $16 go first, then the 250 at $15, then 300 of the 300 at $14. Ending inventory pulls from the oldest layers — 200 units at $12 and 100 units at $14. LIFO creates higher COGS, lower reported profit, and lower taxes in inflationary periods. It's allowed under US GAAP but prohibited under IFRS. That's why you'll see it on American financial statements but almost nowhere else.

Weighted Average Cost smooths everything out. Total cost of goods available for sale divided by total units available. For Dunbar: (200×$12) + (300×$14) + (250×$15) + (150×$16) = $12,550 total cost across 900 units. That's $13.94 per unit (rounded). COGS = 700 × $13.94 = $9,758. Ending inventory = 200 × $13.94 = $2,788. Simple. Stable. Popular for businesses with large volumes of similar items — think fuel distributors, grain elevators, commodity chemicals.

Specific Identification tracks the actual cost of each specific unit sold. Only practical when items are distinct and high-value: cars, jewelry, custom machinery, real estate. If Dunbar sold serialized industrial equipment, this would be the method. For generic widgets? Impossible.

Moving Average (perpetual weighted average) recalculates the average after every purchase. It's the perpetual-inventory cousin of weighted average. More precise. More work. Most ERP systems handle it automatically now.

Why It Matters: The Numbers Aren't Just Numbers

Pick a method. Any method. Now watch what happens to Dunbar's financials.

Under FIFO, gross margin looks healthier. Think about it: the balance sheet shows inventory at current-ish replacement cost. Worth adding: investors like that. In practice, tax authorities? Less so — higher taxable income means a bigger check to the IRS.

Under LIFO, taxable income drops. It distorts working capital ratios. Cash flow improves. Analysts hate that. But the balance sheet carries inventory at 2018 prices (or whenever the base layer formed). And if inventory levels dip into those old layers — "LIFO liquidation" — you get a phantom profit spike from matching ancient costs against current revenue.

Weighted average sits in the middle. No dramatic swings. Plus, no layer management. But it can mask margin erosion if purchase prices are climbing fast.

The method you choose — or inherit — shapes how the business looks to every stakeholder. Banks. Also, buyers. In practice, the board. Even so, the tax man. Yourself, six months from now, trying to explain why margins "suddenly" changed.

How It Works: Walking Through Dunbar's Numbers

Let's do the math together. Not because you can't — but because seeing the mechanics side by side reveals things a summary table hides.

Data Recap

FIFO Calculation

Units sold: 700

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• 200 from beginning @ $12 = $2,400
• 300 from March @ $14 = $4,200
• 200 from July @ $15 = $3,000 COGS = $9,600

Ending inventory (200 units):

• 50 from July @ $15 = $750
• 150 from November @ $16 = $2,400 Ending Inventory = $3,150

Check: $9

600 + $3,150 = $12,750 (Matches Total Available)

LIFO Calculation

Units sold: 700

• 150 from November @ $16 = $2,400
• 250 from July @ $15 = $3,750
• 300 from March @ $14 = $4,200 COGS = $10,350

Ending inventory (200 units):

• 200 from Beginning @ $12 = $2,400 Ending Inventory = $2,400

Check: $10,350 + $2,400 = $12,750 (Matches Total Available)

Weighted Average Calculation

Total Cost of Goods Available: $12,750 Total Units Available: 900 Average Cost per Unit: $14.17 ($12,750 / 900)

COGS (700 units):

• 700 * $14.17 = $9,919

Ending Inventory (200 units):

• 200 * $14.17 = $2,834

Check: $9,919 + $2,834 = $12,753 (Difference due to rounding)

The Comparison: A Summary of Impact

When we lay these results side-by-side, the strategic implications become crystal clear.

In an inflationary environment—where prices are steadily rising from $12 to $16—FIFO makes Dunbar look like a powerhouse. Its COGS is the lowest because it uses the "old, cheap" costs first, resulting in higher reported net income.

Conversely, LIFO makes Dunbar look leaner and less profitable. That's why by matching the most recent, expensive purchases against current sales, it minimizes taxable income. It’s a defensive play designed to keep more cash in the bank, even if the income statement looks "worse" to a potential buyer.

Conclusion: Choosing Your Weapon

There is no "correct" inventory method in a vacuum; there is only the method that aligns with your business strategy and regulatory environment.

If you are a high-growth startup looking to attract venture capital, FIFO might be your best friend, as it presents the strongest margins to investors. Think about it: if you are a mature, cash-heavy manufacturer operating in a period of high inflation, LIFO serves as a vital tool for tax optimization. If you deal with high volumes of homogeneous goods and want to avoid the "noise" of price fluctuations, Weighted Average provides the stability your accounting team will crave.

At the end of the day, the choice of inventory valuation is a pivot point between the Balance Sheet and the Income Statement. Once you commit to a method, consistency is very important. Day to day, switching methods frequently is a red flag to auditors and regulators, signaling that you are "window dressing" your numbers rather than managing your business. Choose your method, master your math, and ensure your records tell the true story of your operations.