In a perpetual inventory system, the maintenance of a separate subsidiary ledger showing data about the individual
items on hand is essential. On February 28, 2009, Best Buy reported inventory totaling $4.753 billion. However,
the company also needs specific information as to the quantity, type, and location of all televisions, cameras,
computers, and the like that make up this sum. That is the significance of a perpetual system; it provides the
ability to keep track of the various types of merchandise. The total cost is available in the inventory T-account
but detailed data about the composition (the quantity and frequently the cost) of merchandise physically held is
maintained in a subsidiary ledger where an individual file can be available for each item.