LIFO (Last In, First Out)

LIFO (Last In, First Out) is an inventory management and accounting method where the most recently received goods are the first ones sold or shipped. Under LIFO, when a warehouse picks an order, it pulls from the newest inventory rather than the oldest stock on the shelf. This stands in contrast to FIFO (First In, First Out), where the oldest inventory moves first. While LIFO has specific advantages for accounting and tax purposes, its implications for physical warehouse operations and product quality are significant, particularly for businesses dealing with perishable goods or products with shelf-life constraints.

LIFO in Warehouse Operations

In a physical warehouse using LIFO, new inventory is placed in the most accessible positions (the front of shelving, the top of a stack, or the nearest pick location), and orders are fulfilled from those positions first. Older inventory gets pushed to the back or the bottom. This approach simplifies put-away because incoming goods go directly to the most convenient spot without rearranging existing stock.

LIFO works well for non-perishable, non-dated products where age does not affect quality or sellability. Building materials, hardware, raw metals, and certain industrial supplies can sit in a warehouse for months without degrading. For these product types, the operational efficiency of LIFO (faster put-away, less product shuffling) outweighs the downside of older stock sitting longer.

For FBA sellers, Amazon’s own fulfillment centers do not follow a strict LIFO or FIFO protocol for most standard products. Amazon’s stowage system distributes incoming inventory across available bin locations based on space optimization algorithms. When fulfilling an order, the system picks from the nearest available unit to the packing station, regardless of when that unit was received. This means sellers cannot rely on Amazon to rotate their stock by date.

LIFO for Accounting and Tax Purposes

LIFO’s primary advantage is in financial reporting. Under LIFO accounting, the cost of goods sold (COGS) on the income statement reflects the most recent (and typically higher) purchase prices. During periods of rising costs, LIFO produces a higher COGS and lower taxable income compared to FIFO. This reduces the company’s tax liability in the current period.

Consider a seller who purchased 1,000 units of a product at $5 each in January and another 1,000 units at $7 each in June. If the seller sells 1,000 units by year-end, LIFO assigns the $7 cost (the most recent purchase) to those sales, resulting in a COGS of $7,000. Under FIFO, the $5 cost would be used, resulting in a COGS of $5,000. LIFO produces $2,000 more in recognized expenses, lowering taxable profit by that amount.

The tax benefit makes LIFO attractive for businesses operating in inflationary environments where input costs rise steadily. However, LIFO is only permitted under U.S. Generally Accepted Accounting Principles (GAAP). International Financial Reporting Standards (IFRS) prohibit LIFO, which means companies reporting under IFRS (required in the EU, UK, and most other countries) must use FIFO or weighted average cost methods.

Drawbacks and Risks

The most significant operational risk of LIFO is inventory obsolescence. Older stock that perpetually sits at the back of the shelf may eventually become unsellable due to packaging degradation, design changes, regulatory updates, or shifting consumer preferences. A seller who stocked a version 1.0 product in January and received version 2.0 in June will, under LIFO, sell all the version 2.0 units first while the outdated version 1.0 stock ages in the warehouse.

For products with expiration dates (supplements, food, beauty products), LIFO is generally not appropriate. Amazon requires that products arriving at fulfillment centers have sufficient remaining shelf life, and selling expired products to consumers creates serious liability and compliance issues. FIFO is the standard and often the regulatory requirement for any date-sensitive inventory.

Choosing Between LIFO and FIFO

The decision depends on product type, industry regulations, and financial strategy. FIFO is the safer choice for consumer goods sold through Amazon FBA, where product freshness and version control matter. LIFO may benefit wholesale or industrial businesses operating under U.S. GAAP that want to minimize current tax exposure during inflationary periods. Consulting with an accountant familiar with both inventory methods and e-commerce operations is advisable before committing to either approach.