Read the following:

Inventories We value inventories at the lower of cost or market as determined primarily by the retail inventory method of accounting, using the last-in, first-out ("LIFO") method for Walmart U.S. segment's inventories. The inventory at the Sam's Club segment is valued using the weighted-average cost LIFO method. When necessary, we record a LIFO provision for the estimated annual effect of inflation, and these estimates are adjusted to actual results determined at year-end. Our LIFO provision is calculated based on inventory levels, markup rates and internally generated retail price indices. As a measure of sensitivity, a 1% increase to our retail price indices would not have resulted in a decrease to the carrying value of inventory. As of January 31, 2019 and 2018, our inventories valued at LIFO approximated those inventories as if they were valued at FIFO.

• What is Walmart's inventory method of accounting (LIFO, FIFO, or some other method--which one)? How is Walmart's inventory method calculated?
• What the inventory method used by Sam's Club (LIFO, FIFO, or some other method--which one)? How is Sam's inventory method calculated?
• What is your perspective on the type of inventory method(s) used by Walmart and Sam's Club?