The inventory costing method that smooths out erratic changes in costs is:

The inventory cost flow assumption states that the cost of an inventory item changes from when it is acquired or built and when it is sold. Because of this cost differential, management needs a formal system for assigning costs to inventory as they transition to sellable goods.

Example of the Inventory Cost Flow Assumption

For example, ABC International buys a widget on January 1 for $50. On July 1, it buys an identical widget for $70, and on November 1 it buys yet another identical widget for $90. The products are completely interchangeable. On December 1, the company sells one of the widgets. It bought the widgets at three different prices, so what cost should it report for its cost of goods sold? There are several possible ways to interpret the cost flow assumption. For example:

• FIFO cost flow assumption. Under the first in, first out method, you assume that the first item purchased is also the first one sold. Thus, the cost of goods sold would be $50. Since this is the lowest-cost item in the example, profits would be highest under FIFO.

• LIFO cost flow assumption. Under the last in, first out method, you assume that the last item purchased is also the first one sold. Thus, the cost of goods sold would be $90. Since this is the highest-cost item in the example, profits would be lowest under LIFO.

• Specific identification method. Under the specific identification method, you can physically identify which specific items are purchased and then sold, so the cost flow moves with the actual item sold. This is a rare situation, since most items are not individually identifiable.

• Weighted average cost flow assumption. Under the weighted average method, the cost of goods sold is the average cost of all three units, or $70. This cost flow assumption tends to yield a mid-range cost, and therefore also a mid-range profit.

Additional Inventory Cost Flow Assumption Issues

The cost flow assumption does not necessarily match the actual flow of goods (if that were the case, most companies would use the FIFO method). Instead, it is allowable to use a cost flow assumption that varies from actual usage. For this reason, companies tend to select a cost flow assumption that either minimizes profits (in order to minimize income taxes) or maximize profits (in order to increase share value).

In periods of rising materials prices, the LIFO method results in a higher cost of goods sold, lower profits, and therefore lower income taxes. In periods of declining materials prices, the FIFO method yields the same results.

The cost flow assumption is a minor item when inventory costs are relatively stable over the long term, since there will be no particular difference in the cost of goods sold, no matter which cost flow assumption is used. Conversely, dramatic changes in inventory costs over time will yield a considerable difference in reported profit levels, depending on the cost flow assumption used. Thus, the accountant should be especially aware of the financial impact of the inventory cost flow assumption in periods of fluctuating costs.

All of the preceding issues are of less importance if the weighted average method is used. This approach tends to yield average profit levels and average levels of taxable income over time.

Note that the LIFO method is not allowed under IFRS. If this stance is adopted by other accounting frameworks in the future, it is possible that the LIFO method may not be available as a cost flow assumption.

Last in, first out (LIFO) is a method used to account for inventory that records the most recently produced items as sold first. Under LIFO, the cost of the most recent products purchased (or produced) are the first to be expensed as cost of goods sold (COGS), which means the lower cost of older products will be reported as inventory.

Two alternative methods of inventory-costing include first in, first out (FIFO), where the oldest inventory items are recorded as sold first, and the average cost method, which takes the weighted average of all units available for sale during the accounting period and then uses that average cost to determine COGS and ending inventory.

Key Takeaways

• Last in, first out (LIFO) is a method used to account for inventory.
• Under LIFO, the costs of the most recent products purchased (or produced) are the first to be expensed.
• LIFO is used only in the United States and governed by the generally accepted accounting principles (GAAP).
• Other methods to account for inventory include first in, first out (FIFO) and the average cost method.
• Using LIFO typically lowers net income but is tax advantageous when prices are rising.

Understanding Last In, First Out (LIFO)

Last in, first out (LIFO) is only used in the United States where all three inventory-costing methods can be used under generally accepted accounting principles (GAAP). The International Financial Reporting Standards (IFRS) forbids the use of the LIFO method.

Companies that use LIFO inventory valuations are typically those with relatively large inventories, such as retailers or auto dealerships, that can take advantage of lower taxes (when prices are rising) and higher cash flows.

Many U.S. companies prefer to use FIFO though, because if a firm uses a LIFO valuation when it files taxes, it must also use LIFO when it reports financial results to shareholders, which lowers net income and, ultimately, earnings per share.

Last In, First Out (LIFO), Inflation, and Net Income

When there is zero inflation, all three inventory-costing methods produce the same result. But if inflation is high, the choice of accounting method can dramatically affect valuation ratios. FIFO, LIFO, and average cost have a different impact:

• FIFO provides a better indication of the value of ending inventory (on the balance sheet), but it also increases net income because inventory that might be several years old is used to value COGS. Increasing net income sounds good, but it can increase the taxes that a company must pay.
• LIFO is not a good indicator of ending inventory value because it may understate the value of inventory. LIFO results in lower net income (and taxes) because COGS is higher. However, there are fewer inventory write-downs under LIFO during inflation.
• Average cost produces results that fall somewhere between FIFO and LIFO.

If prices are decreasing, then the complete opposite of the above is true.

Example of Last In, First Out (LIFO)

Assume company A has 10 widgets. The first five widgets cost $100 each and arrived two days ago. The last five widgets cost $200 each and arrived one day ago. Based on the LIFO method of inventory management, the last widgets in are the first ones to be sold. Seven widgets are sold, but how much can the accountant record as a cost?

Each widget has the same sales price, so revenue is the same, but the cost of the widgets is based on the inventory method selected. Based on the LIFO method, the last inventory in is the first inventory sold. This means the widgets that cost $200 sold first. The company then sold two more of the $100 widgets. In total, the cost of the widgets under the LIFO method is $1,200, or five at $200 and two at $100. In contrast, using FIFO, the $100 widgets are sold first, followed by the $200 widgets. So, the cost of the widgets sold will be recorded as $900, or five at $100 and two at $200.

This is why in periods of rising prices, LIFO creates higher costs and lowers net income, which also reduces taxable income. Likewise, in periods of falling prices, LIFO creates lower costs and increases net income, which also increases taxable income.

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