What is the effect of using FIFO compared to LIFO on the gross profit margin in an environment of declining inventory unit costs?

In an environment of declining inventory unit costs, using FIFO results in a lower cost of goods sold compared to LIFO. This leads to a higher gross profit margin for FIFO, as it reflects the cost of older, higher-priced inventory being sold first, while LIFO sells newer, lower-cost inventory first.

When inventory costs are declining, FIFO (First-In, First-Out) results in a lower cost of goods sold because it sells the older, higher-cost inventory first. In contrast, LIFO (Last-In, First-Out) sells the newer, lower-cost inventory first, which increases the cost of goods sold. Consequently, FIFO yields a higher gross profit margin than LIFO in such an environment, as the gross profit margin is calculated as sales revenue minus cost of goods sold.